2017-11-30 20:43:25 +08:00
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//===-- MCObjectFileInfo.cpp - Object File Information --------------------===//
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//
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2019-01-19 16:50:56 +08:00
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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2017-11-30 20:43:25 +08:00
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/MC/MCObjectFileInfo.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/ADT/Triple.h"
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#include "llvm/BinaryFormat/COFF.h"
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#include "llvm/BinaryFormat/ELF.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCSection.h"
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#include "llvm/MC/MCSectionCOFF.h"
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#include "llvm/MC/MCSectionELF.h"
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#include "llvm/MC/MCSectionMachO.h"
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#include "llvm/MC/MCSectionWasm.h"
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2019-07-10 03:21:01 +08:00
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#include "llvm/MC/MCSectionXCOFF.h"
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2017-11-30 20:43:25 +08:00
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using namespace llvm;
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static bool useCompactUnwind(const Triple &T) {
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// Only on darwin.
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if (!T.isOSDarwin())
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return false;
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// aarch64 always has it.
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2019-09-12 18:22:23 +08:00
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if (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32)
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2017-11-30 20:43:25 +08:00
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return true;
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// armv7k always has it.
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if (T.isWatchABI())
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return true;
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// Use it on newer version of OS X.
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if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
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return true;
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// And the iOS simulator.
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2020-01-07 17:32:39 +08:00
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if (T.isiOS() && T.isX86())
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2017-11-30 20:43:25 +08:00
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return true;
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return false;
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}
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void MCObjectFileInfo::initMachOMCObjectFileInfo(const Triple &T) {
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// MachO
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SupportsWeakOmittedEHFrame = false;
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EHFrameSection = Ctx->getMachOSection(
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"__TEXT", "__eh_frame",
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MachO::S_COALESCED | MachO::S_ATTR_NO_TOC |
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MachO::S_ATTR_STRIP_STATIC_SYMS | MachO::S_ATTR_LIVE_SUPPORT,
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SectionKind::getReadOnly());
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2019-09-12 18:22:23 +08:00
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if (T.isOSDarwin() &&
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(T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32))
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2017-11-30 20:43:25 +08:00
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SupportsCompactUnwindWithoutEHFrame = true;
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if (T.isWatchABI())
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OmitDwarfIfHaveCompactUnwind = true;
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[MC] Move EH DWARF encodings from MC to CodeGen, NFC
Summary:
The TType encoding, LSDA encoding, and personality encoding are all
passed explicitly by CodeGen to the assembler through .cfi_* directives,
so only the AsmPrinter needs to know about them.
The FDE CFI encoding however, controls the encoding of the label
implicitly created by the .cfi_startproc directive. That directive seems
to be special in that it doesn't take an encoding, so the assembler just
has to know how to encode one DSO-local label reference from .eh_frame
to .text.
As a result, it looks like MC will continue to have to know when the
large code model is in use. Perhaps we could invent a '.cfi_startproc
[large]' flag so that this knowledge doesn't need to pollute the
assembler.
Reviewers: davide, lliu0, JDevlieghere
Subscribers: hiraditya, fedor.sergeev, llvm-commits
Differential Revision: https://reviews.llvm.org/D50533
llvm-svn: 339397
2018-08-10 06:24:04 +08:00
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FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
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2017-11-30 20:43:25 +08:00
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// .comm doesn't support alignment before Leopard.
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if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
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CommDirectiveSupportsAlignment = false;
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TextSection // .text
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= Ctx->getMachOSection("__TEXT", "__text",
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MachO::S_ATTR_PURE_INSTRUCTIONS,
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SectionKind::getText());
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DataSection // .data
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= Ctx->getMachOSection("__DATA", "__data", 0, SectionKind::getData());
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// BSSSection might not be expected initialized on msvc.
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BSSSection = nullptr;
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TLSDataSection // .tdata
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= Ctx->getMachOSection("__DATA", "__thread_data",
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MachO::S_THREAD_LOCAL_REGULAR,
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SectionKind::getData());
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TLSBSSSection // .tbss
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= Ctx->getMachOSection("__DATA", "__thread_bss",
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MachO::S_THREAD_LOCAL_ZEROFILL,
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SectionKind::getThreadBSS());
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// TODO: Verify datarel below.
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TLSTLVSection // .tlv
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= Ctx->getMachOSection("__DATA", "__thread_vars",
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MachO::S_THREAD_LOCAL_VARIABLES,
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SectionKind::getData());
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TLSThreadInitSection = Ctx->getMachOSection(
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"__DATA", "__thread_init", MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
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SectionKind::getData());
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CStringSection // .cstring
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= Ctx->getMachOSection("__TEXT", "__cstring",
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MachO::S_CSTRING_LITERALS,
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SectionKind::getMergeable1ByteCString());
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UStringSection
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= Ctx->getMachOSection("__TEXT","__ustring", 0,
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SectionKind::getMergeable2ByteCString());
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FourByteConstantSection // .literal4
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= Ctx->getMachOSection("__TEXT", "__literal4",
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MachO::S_4BYTE_LITERALS,
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SectionKind::getMergeableConst4());
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EightByteConstantSection // .literal8
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= Ctx->getMachOSection("__TEXT", "__literal8",
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MachO::S_8BYTE_LITERALS,
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SectionKind::getMergeableConst8());
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SixteenByteConstantSection // .literal16
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= Ctx->getMachOSection("__TEXT", "__literal16",
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MachO::S_16BYTE_LITERALS,
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SectionKind::getMergeableConst16());
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ReadOnlySection // .const
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= Ctx->getMachOSection("__TEXT", "__const", 0,
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SectionKind::getReadOnly());
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// If the target is not powerpc, map the coal sections to the non-coal
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// sections.
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//
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// "__TEXT/__textcoal_nt" => section "__TEXT/__text"
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// "__TEXT/__const_coal" => section "__TEXT/__const"
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// "__DATA/__datacoal_nt" => section "__DATA/__data"
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Triple::ArchType ArchTy = T.getArch();
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2018-04-11 04:16:35 +08:00
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ConstDataSection // .const_data
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= Ctx->getMachOSection("__DATA", "__const", 0,
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SectionKind::getReadOnlyWithRel());
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2017-11-30 20:43:25 +08:00
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if (ArchTy == Triple::ppc || ArchTy == Triple::ppc64) {
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TextCoalSection
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= Ctx->getMachOSection("__TEXT", "__textcoal_nt",
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MachO::S_COALESCED |
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MachO::S_ATTR_PURE_INSTRUCTIONS,
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SectionKind::getText());
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ConstTextCoalSection
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= Ctx->getMachOSection("__TEXT", "__const_coal",
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MachO::S_COALESCED,
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SectionKind::getReadOnly());
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DataCoalSection = Ctx->getMachOSection(
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"__DATA", "__datacoal_nt", MachO::S_COALESCED, SectionKind::getData());
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2018-04-11 04:16:35 +08:00
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ConstDataCoalSection = DataCoalSection;
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2017-11-30 20:43:25 +08:00
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} else {
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TextCoalSection = TextSection;
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ConstTextCoalSection = ReadOnlySection;
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DataCoalSection = DataSection;
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2018-04-11 04:16:35 +08:00
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ConstDataCoalSection = ConstDataSection;
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2017-11-30 20:43:25 +08:00
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}
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DataCommonSection
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= Ctx->getMachOSection("__DATA","__common",
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MachO::S_ZEROFILL,
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SectionKind::getBSS());
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DataBSSSection
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= Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
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SectionKind::getBSS());
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LazySymbolPointerSection
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= Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
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MachO::S_LAZY_SYMBOL_POINTERS,
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SectionKind::getMetadata());
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NonLazySymbolPointerSection
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= Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
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MachO::S_NON_LAZY_SYMBOL_POINTERS,
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SectionKind::getMetadata());
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ThreadLocalPointerSection
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= Ctx->getMachOSection("__DATA", "__thread_ptr",
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MachO::S_THREAD_LOCAL_VARIABLE_POINTERS,
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SectionKind::getMetadata());
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// Exception Handling.
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LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
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SectionKind::getReadOnlyWithRel());
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COFFDebugSymbolsSection = nullptr;
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COFFDebugTypesSection = nullptr;
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2017-12-14 06:33:58 +08:00
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COFFGlobalTypeHashesSection = nullptr;
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2017-11-30 20:43:25 +08:00
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if (useCompactUnwind(T)) {
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CompactUnwindSection =
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Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
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SectionKind::getReadOnly());
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2020-01-07 17:32:39 +08:00
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if (T.isX86())
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2017-11-30 20:43:25 +08:00
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CompactUnwindDwarfEHFrameOnly = 0x04000000; // UNWIND_X86_64_MODE_DWARF
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2019-09-12 18:22:23 +08:00
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else if (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32)
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2017-11-30 20:43:25 +08:00
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CompactUnwindDwarfEHFrameOnly = 0x03000000; // UNWIND_ARM64_MODE_DWARF
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else if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb)
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CompactUnwindDwarfEHFrameOnly = 0x04000000; // UNWIND_ARM_MODE_DWARF
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}
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// Debug Information.
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2018-04-04 22:42:14 +08:00
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DwarfDebugNamesSection =
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Ctx->getMachOSection("__DWARF", "__debug_names", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "debug_names_begin");
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2017-11-30 20:43:25 +08:00
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DwarfAccelNamesSection =
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Ctx->getMachOSection("__DWARF", "__apple_names", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "names_begin");
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DwarfAccelObjCSection =
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Ctx->getMachOSection("__DWARF", "__apple_objc", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "objc_begin");
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// 16 character section limit...
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DwarfAccelNamespaceSection =
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Ctx->getMachOSection("__DWARF", "__apple_namespac", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "namespac_begin");
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DwarfAccelTypesSection =
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Ctx->getMachOSection("__DWARF", "__apple_types", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "types_begin");
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DwarfSwiftASTSection =
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Ctx->getMachOSection("__DWARF", "__swift_ast", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata());
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DwarfAbbrevSection =
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Ctx->getMachOSection("__DWARF", "__debug_abbrev", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "section_abbrev");
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DwarfInfoSection =
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Ctx->getMachOSection("__DWARF", "__debug_info", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "section_info");
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DwarfLineSection =
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Ctx->getMachOSection("__DWARF", "__debug_line", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "section_line");
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2018-02-07 04:29:21 +08:00
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DwarfLineStrSection =
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Ctx->getMachOSection("__DWARF", "__debug_line_str", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "section_line_str");
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2017-11-30 20:43:25 +08:00
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DwarfFrameSection =
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Ctx->getMachOSection("__DWARF", "__debug_frame", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata());
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DwarfPubNamesSection =
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Ctx->getMachOSection("__DWARF", "__debug_pubnames", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata());
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DwarfPubTypesSection =
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Ctx->getMachOSection("__DWARF", "__debug_pubtypes", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata());
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DwarfGnuPubNamesSection =
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Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata());
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DwarfGnuPubTypesSection =
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Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata());
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DwarfStrSection =
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Ctx->getMachOSection("__DWARF", "__debug_str", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "info_string");
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DwarfStrOffSection =
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Ctx->getMachOSection("__DWARF", "__debug_str_offs", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "section_str_off");
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2018-10-20 16:55:51 +08:00
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DwarfAddrSection =
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Ctx->getMachOSection("__DWARF", "__debug_addr", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "section_info");
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2017-11-30 20:43:25 +08:00
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DwarfLocSection =
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Ctx->getMachOSection("__DWARF", "__debug_loc", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "section_debug_loc");
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2018-10-26 19:25:12 +08:00
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DwarfLoclistsSection =
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Ctx->getMachOSection("__DWARF", "__debug_loclists", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "section_debug_loc");
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2017-11-30 20:43:25 +08:00
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DwarfARangesSection =
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Ctx->getMachOSection("__DWARF", "__debug_aranges", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata());
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DwarfRangesSection =
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Ctx->getMachOSection("__DWARF", "__debug_ranges", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "debug_range");
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2018-07-13 02:18:21 +08:00
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DwarfRnglistsSection =
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Ctx->getMachOSection("__DWARF", "__debug_rnglists", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "debug_range");
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2017-11-30 20:43:25 +08:00
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DwarfMacinfoSection =
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Ctx->getMachOSection("__DWARF", "__debug_macinfo", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "debug_macinfo");
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2020-04-03 15:14:09 +08:00
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DwarfMacroSection =
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Ctx->getMachOSection("__DWARF", "__debug_macro", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata(), "debug_macro");
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2017-11-30 20:43:25 +08:00
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DwarfDebugInlineSection =
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Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata());
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DwarfCUIndexSection =
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Ctx->getMachOSection("__DWARF", "__debug_cu_index", MachO::S_ATTR_DEBUG,
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SectionKind::getMetadata());
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DwarfTUIndexSection =
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Ctx->getMachOSection("__DWARF", "__debug_tu_index", MachO::S_ATTR_DEBUG,
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|
|
SectionKind::getMetadata());
|
|
|
|
StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
|
|
|
|
0, SectionKind::getMetadata());
|
|
|
|
|
|
|
|
FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
|
|
|
|
0, SectionKind::getMetadata());
|
|
|
|
|
2019-03-27 09:13:59 +08:00
|
|
|
RemarksSection = Ctx->getMachOSection(
|
|
|
|
"__LLVM", "__remarks", MachO::S_ATTR_DEBUG, SectionKind::getMetadata());
|
|
|
|
|
2017-11-30 20:43:25 +08:00
|
|
|
TLSExtraDataSection = TLSTLVSection;
|
|
|
|
}
|
|
|
|
|
|
|
|
void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
|
|
|
|
switch (T.getArch()) {
|
|
|
|
case Triple::mips:
|
|
|
|
case Triple::mipsel:
|
|
|
|
case Triple::mips64:
|
|
|
|
case Triple::mips64el:
|
2020-01-12 18:55:15 +08:00
|
|
|
// We cannot use DW_EH_PE_sdata8 for the large PositionIndependent case
|
|
|
|
// since there is no R_MIPS_PC64 relocation (only a 32-bit version).
|
|
|
|
if (PositionIndependent && !Large)
|
|
|
|
FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
|
|
|
|
else
|
|
|
|
FDECFIEncoding = Ctx->getAsmInfo()->getCodePointerSize() == 4
|
|
|
|
? dwarf::DW_EH_PE_sdata4
|
|
|
|
: dwarf::DW_EH_PE_sdata8;
|
2017-11-30 20:43:25 +08:00
|
|
|
break;
|
2018-03-24 08:07:38 +08:00
|
|
|
case Triple::ppc64:
|
|
|
|
case Triple::ppc64le:
|
2020-11-07 03:26:04 +08:00
|
|
|
case Triple::aarch64:
|
|
|
|
case Triple::aarch64_be:
|
2017-11-30 20:43:25 +08:00
|
|
|
case Triple::x86_64:
|
|
|
|
FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
|
|
|
|
(Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);
|
|
|
|
break;
|
|
|
|
case Triple::bpfel:
|
|
|
|
case Triple::bpfeb:
|
|
|
|
FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
|
|
|
|
break;
|
|
|
|
case Triple::hexagon:
|
[MC] Move EH DWARF encodings from MC to CodeGen, NFC
Summary:
The TType encoding, LSDA encoding, and personality encoding are all
passed explicitly by CodeGen to the assembler through .cfi_* directives,
so only the AsmPrinter needs to know about them.
The FDE CFI encoding however, controls the encoding of the label
implicitly created by the .cfi_startproc directive. That directive seems
to be special in that it doesn't take an encoding, so the assembler just
has to know how to encode one DSO-local label reference from .eh_frame
to .text.
As a result, it looks like MC will continue to have to know when the
large code model is in use. Perhaps we could invent a '.cfi_startproc
[large]' flag so that this knowledge doesn't need to pollute the
assembler.
Reviewers: davide, lliu0, JDevlieghere
Subscribers: hiraditya, fedor.sergeev, llvm-commits
Differential Revision: https://reviews.llvm.org/D50533
llvm-svn: 339397
2018-08-10 06:24:04 +08:00
|
|
|
FDECFIEncoding =
|
|
|
|
PositionIndependent ? dwarf::DW_EH_PE_pcrel : dwarf::DW_EH_PE_absptr;
|
2018-08-10 19:02:44 +08:00
|
|
|
break;
|
2017-11-30 20:43:25 +08:00
|
|
|
default:
|
[MC] Move EH DWARF encodings from MC to CodeGen, NFC
Summary:
The TType encoding, LSDA encoding, and personality encoding are all
passed explicitly by CodeGen to the assembler through .cfi_* directives,
so only the AsmPrinter needs to know about them.
The FDE CFI encoding however, controls the encoding of the label
implicitly created by the .cfi_startproc directive. That directive seems
to be special in that it doesn't take an encoding, so the assembler just
has to know how to encode one DSO-local label reference from .eh_frame
to .text.
As a result, it looks like MC will continue to have to know when the
large code model is in use. Perhaps we could invent a '.cfi_startproc
[large]' flag so that this knowledge doesn't need to pollute the
assembler.
Reviewers: davide, lliu0, JDevlieghere
Subscribers: hiraditya, fedor.sergeev, llvm-commits
Differential Revision: https://reviews.llvm.org/D50533
llvm-svn: 339397
2018-08-10 06:24:04 +08:00
|
|
|
FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
|
2017-11-30 20:43:25 +08:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
unsigned EHSectionType = T.getArch() == Triple::x86_64
|
|
|
|
? ELF::SHT_X86_64_UNWIND
|
|
|
|
: ELF::SHT_PROGBITS;
|
|
|
|
|
|
|
|
// Solaris requires different flags for .eh_frame to seemingly every other
|
|
|
|
// platform.
|
|
|
|
unsigned EHSectionFlags = ELF::SHF_ALLOC;
|
|
|
|
if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
|
|
|
|
EHSectionFlags |= ELF::SHF_WRITE;
|
|
|
|
|
|
|
|
// ELF
|
|
|
|
BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
|
|
|
|
ELF::SHF_WRITE | ELF::SHF_ALLOC);
|
|
|
|
|
|
|
|
TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
|
|
|
|
ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
|
|
|
|
|
|
|
|
DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
|
|
|
|
ELF::SHF_WRITE | ELF::SHF_ALLOC);
|
|
|
|
|
|
|
|
ReadOnlySection =
|
|
|
|
Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
|
|
|
|
|
|
|
|
TLSDataSection =
|
|
|
|
Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
|
|
|
|
ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
|
|
|
|
|
|
|
|
TLSBSSSection = Ctx->getELFSection(
|
|
|
|
".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
|
|
|
|
|
|
|
|
DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
|
|
|
|
ELF::SHF_ALLOC | ELF::SHF_WRITE);
|
|
|
|
|
|
|
|
MergeableConst4Section =
|
|
|
|
Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
|
2021-02-01 14:42:35 +08:00
|
|
|
ELF::SHF_ALLOC | ELF::SHF_MERGE, 4);
|
2017-11-30 20:43:25 +08:00
|
|
|
|
|
|
|
MergeableConst8Section =
|
|
|
|
Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
|
2021-02-01 14:42:35 +08:00
|
|
|
ELF::SHF_ALLOC | ELF::SHF_MERGE, 8);
|
2017-11-30 20:43:25 +08:00
|
|
|
|
|
|
|
MergeableConst16Section =
|
|
|
|
Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
|
2021-02-01 14:42:35 +08:00
|
|
|
ELF::SHF_ALLOC | ELF::SHF_MERGE, 16);
|
2017-11-30 20:43:25 +08:00
|
|
|
|
|
|
|
MergeableConst32Section =
|
|
|
|
Ctx->getELFSection(".rodata.cst32", ELF::SHT_PROGBITS,
|
2021-02-01 14:42:35 +08:00
|
|
|
ELF::SHF_ALLOC | ELF::SHF_MERGE, 32);
|
2017-11-30 20:43:25 +08:00
|
|
|
|
|
|
|
// Exception Handling Sections.
|
|
|
|
|
|
|
|
// FIXME: We're emitting LSDA info into a readonly section on ELF, even though
|
|
|
|
// it contains relocatable pointers. In PIC mode, this is probably a big
|
|
|
|
// runtime hit for C++ apps. Either the contents of the LSDA need to be
|
|
|
|
// adjusted or this should be a data section.
|
|
|
|
LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
|
|
|
|
ELF::SHF_ALLOC);
|
|
|
|
|
|
|
|
COFFDebugSymbolsSection = nullptr;
|
|
|
|
COFFDebugTypesSection = nullptr;
|
|
|
|
|
|
|
|
unsigned DebugSecType = ELF::SHT_PROGBITS;
|
|
|
|
|
|
|
|
// MIPS .debug_* sections should have SHT_MIPS_DWARF section type
|
|
|
|
// to distinguish among sections contain DWARF and ECOFF debug formats.
|
|
|
|
// Sections with ECOFF debug format are obsoleted and marked by SHT_PROGBITS.
|
2018-06-26 00:49:20 +08:00
|
|
|
if (T.isMIPS())
|
2017-11-30 20:43:25 +08:00
|
|
|
DebugSecType = ELF::SHT_MIPS_DWARF;
|
|
|
|
|
|
|
|
// Debug Info Sections.
|
|
|
|
DwarfAbbrevSection =
|
|
|
|
Ctx->getELFSection(".debug_abbrev", DebugSecType, 0);
|
|
|
|
DwarfInfoSection = Ctx->getELFSection(".debug_info", DebugSecType, 0);
|
|
|
|
DwarfLineSection = Ctx->getELFSection(".debug_line", DebugSecType, 0);
|
2018-02-07 04:29:21 +08:00
|
|
|
DwarfLineStrSection =
|
|
|
|
Ctx->getELFSection(".debug_line_str", DebugSecType,
|
2021-02-01 14:42:35 +08:00
|
|
|
ELF::SHF_MERGE | ELF::SHF_STRINGS, 1);
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfFrameSection = Ctx->getELFSection(".debug_frame", DebugSecType, 0);
|
|
|
|
DwarfPubNamesSection =
|
|
|
|
Ctx->getELFSection(".debug_pubnames", DebugSecType, 0);
|
|
|
|
DwarfPubTypesSection =
|
|
|
|
Ctx->getELFSection(".debug_pubtypes", DebugSecType, 0);
|
|
|
|
DwarfGnuPubNamesSection =
|
|
|
|
Ctx->getELFSection(".debug_gnu_pubnames", DebugSecType, 0);
|
|
|
|
DwarfGnuPubTypesSection =
|
|
|
|
Ctx->getELFSection(".debug_gnu_pubtypes", DebugSecType, 0);
|
|
|
|
DwarfStrSection =
|
|
|
|
Ctx->getELFSection(".debug_str", DebugSecType,
|
2021-02-01 14:42:35 +08:00
|
|
|
ELF::SHF_MERGE | ELF::SHF_STRINGS, 1);
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfLocSection = Ctx->getELFSection(".debug_loc", DebugSecType, 0);
|
|
|
|
DwarfARangesSection =
|
|
|
|
Ctx->getELFSection(".debug_aranges", DebugSecType, 0);
|
|
|
|
DwarfRangesSection =
|
|
|
|
Ctx->getELFSection(".debug_ranges", DebugSecType, 0);
|
|
|
|
DwarfMacinfoSection =
|
|
|
|
Ctx->getELFSection(".debug_macinfo", DebugSecType, 0);
|
2020-04-03 15:14:09 +08:00
|
|
|
DwarfMacroSection = Ctx->getELFSection(".debug_macro", DebugSecType, 0);
|
2017-11-30 20:43:25 +08:00
|
|
|
|
|
|
|
// DWARF5 Experimental Debug Info
|
|
|
|
|
|
|
|
// Accelerator Tables
|
2018-04-04 22:42:14 +08:00
|
|
|
DwarfDebugNamesSection =
|
|
|
|
Ctx->getELFSection(".debug_names", ELF::SHT_PROGBITS, 0);
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfAccelNamesSection =
|
|
|
|
Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0);
|
|
|
|
DwarfAccelObjCSection =
|
|
|
|
Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0);
|
|
|
|
DwarfAccelNamespaceSection =
|
|
|
|
Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0);
|
|
|
|
DwarfAccelTypesSection =
|
|
|
|
Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0);
|
|
|
|
|
|
|
|
// String Offset and Address Sections
|
|
|
|
DwarfStrOffSection =
|
|
|
|
Ctx->getELFSection(".debug_str_offsets", DebugSecType, 0);
|
|
|
|
DwarfAddrSection = Ctx->getELFSection(".debug_addr", DebugSecType, 0);
|
2018-07-13 02:18:21 +08:00
|
|
|
DwarfRnglistsSection = Ctx->getELFSection(".debug_rnglists", DebugSecType, 0);
|
2018-10-26 19:25:12 +08:00
|
|
|
DwarfLoclistsSection = Ctx->getELFSection(".debug_loclists", DebugSecType, 0);
|
2017-11-30 20:43:25 +08:00
|
|
|
|
|
|
|
// Fission Sections
|
|
|
|
DwarfInfoDWOSection =
|
2018-09-22 15:36:20 +08:00
|
|
|
Ctx->getELFSection(".debug_info.dwo", DebugSecType, ELF::SHF_EXCLUDE);
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfTypesDWOSection =
|
2018-09-22 15:36:20 +08:00
|
|
|
Ctx->getELFSection(".debug_types.dwo", DebugSecType, ELF::SHF_EXCLUDE);
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfAbbrevDWOSection =
|
2018-09-22 15:36:20 +08:00
|
|
|
Ctx->getELFSection(".debug_abbrev.dwo", DebugSecType, ELF::SHF_EXCLUDE);
|
|
|
|
DwarfStrDWOSection = Ctx->getELFSection(
|
|
|
|
".debug_str.dwo", DebugSecType,
|
2021-02-01 14:42:35 +08:00
|
|
|
ELF::SHF_MERGE | ELF::SHF_STRINGS | ELF::SHF_EXCLUDE, 1);
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfLineDWOSection =
|
2018-09-22 15:36:20 +08:00
|
|
|
Ctx->getELFSection(".debug_line.dwo", DebugSecType, ELF::SHF_EXCLUDE);
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfLocDWOSection =
|
2018-09-22 15:36:20 +08:00
|
|
|
Ctx->getELFSection(".debug_loc.dwo", DebugSecType, ELF::SHF_EXCLUDE);
|
|
|
|
DwarfStrOffDWOSection = Ctx->getELFSection(".debug_str_offsets.dwo",
|
|
|
|
DebugSecType, ELF::SHF_EXCLUDE);
|
2018-07-13 02:18:21 +08:00
|
|
|
DwarfRnglistsDWOSection =
|
2018-09-22 15:36:20 +08:00
|
|
|
Ctx->getELFSection(".debug_rnglists.dwo", DebugSecType, ELF::SHF_EXCLUDE);
|
2019-11-11 15:23:19 +08:00
|
|
|
DwarfMacinfoDWOSection =
|
|
|
|
Ctx->getELFSection(".debug_macinfo.dwo", DebugSecType, ELF::SHF_EXCLUDE);
|
2020-05-30 13:41:09 +08:00
|
|
|
DwarfMacroDWOSection =
|
|
|
|
Ctx->getELFSection(".debug_macro.dwo", DebugSecType, ELF::SHF_EXCLUDE);
|
2017-11-30 20:43:25 +08:00
|
|
|
|
2019-11-23 22:34:36 +08:00
|
|
|
DwarfLoclistsDWOSection =
|
|
|
|
Ctx->getELFSection(".debug_loclists.dwo", DebugSecType, ELF::SHF_EXCLUDE);
|
|
|
|
|
2017-11-30 20:43:25 +08:00
|
|
|
// DWP Sections
|
|
|
|
DwarfCUIndexSection =
|
|
|
|
Ctx->getELFSection(".debug_cu_index", DebugSecType, 0);
|
|
|
|
DwarfTUIndexSection =
|
|
|
|
Ctx->getELFSection(".debug_tu_index", DebugSecType, 0);
|
|
|
|
|
|
|
|
StackMapSection =
|
|
|
|
Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
|
|
|
|
|
|
|
|
FaultMapSection =
|
|
|
|
Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
|
|
|
|
|
|
|
|
EHFrameSection =
|
|
|
|
Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
|
2017-11-30 21:05:14 +08:00
|
|
|
|
|
|
|
StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
|
[CSSPGO] Pseudo probe encoding and emission.
This change implements pseudo probe encoding and emission for CSSPGO. Please see RFC here for more context: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s
Pseudo probes are in the form of intrinsic calls on IR/MIR but they do not turn into any machine instructions. Instead they are emitted into the binary as a piece of data in standalone sections. The probe-specific sections are not needed to be loaded into memory at execution time, thus they do not incur a runtime overhead.
**ELF object emission**
The binary data to emit are organized as two ELF sections, i.e, the `.pseudo_probe_desc` section and the `.pseudo_probe` section. The `.pseudo_probe_desc` section stores a function descriptor for each function and the `.pseudo_probe` section stores the actual probes, each fo which corresponds to an IR basic block or an IR function callsite. A function descriptor is stored as a module-level metadata during the compilation and is serialized into the object file during object emission.
Both the probe descriptors and pseudo probes can be emitted into a separate ELF section per function to leverage the linker for deduplication. A `.pseudo_probe` section shares the same COMDAT group with the function code so that when the function is dead, the probes are dead and disposed too. On the contrary, a `.pseudo_probe_desc` section has its own COMDAT group. This is because even if a function is dead, its probes may be inlined into other functions and its descriptor is still needed by the profile generation tool.
The format of `.pseudo_probe_desc` section looks like:
```
.section .pseudo_probe_desc,"",@progbits
.quad 6309742469962978389 // Func GUID
.quad 4294967295 // Func Hash
.byte 9 // Length of func name
.ascii "_Z5funcAi" // Func name
.quad 7102633082150537521
.quad 138828622701
.byte 12
.ascii "_Z8funcLeafi"
.quad 446061515086924981
.quad 4294967295
.byte 9
.ascii "_Z5funcBi"
.quad -2016976694713209516
.quad 72617220756
.byte 7
.ascii "_Z3fibi"
```
For each `.pseudoprobe` section, the encoded binary data consists of a single function record corresponding to an outlined function (i.e, a function with a code entry in the `.text` section). A function record has the following format :
```
FUNCTION BODY (one for each outlined function present in the text section)
GUID (uint64)
GUID of the function
NPROBES (ULEB128)
Number of probes originating from this function.
NUM_INLINED_FUNCTIONS (ULEB128)
Number of callees inlined into this function, aka number of
first-level inlinees
PROBE RECORDS
A list of NPROBES entries. Each entry contains:
INDEX (ULEB128)
TYPE (uint4)
0 - block probe, 1 - indirect call, 2 - direct call
ATTRIBUTE (uint3)
reserved
ADDRESS_TYPE (uint1)
0 - code address, 1 - address delta
CODE_ADDRESS (uint64 or ULEB128)
code address or address delta, depending on ADDRESS_TYPE
INLINED FUNCTION RECORDS
A list of NUM_INLINED_FUNCTIONS entries describing each of the inlined
callees. Each record contains:
INLINE SITE
GUID of the inlinee (uint64)
ID of the callsite probe (ULEB128)
FUNCTION BODY
A FUNCTION BODY entry describing the inlined function.
```
To support building a context-sensitive profile, probes from inlinees are grouped by their inline contexts. An inline context is logically a call path through which a callee function lands in a caller function. The probe emitter builds an inline tree based on the debug metadata for each outlined function in the form of a trie tree. A tree root is the outlined function. Each tree edge stands for a callsite where inlining happens. Pseudo probes originating from an inlinee function are stored in a tree node and the tree path starting from the root all the way down to the tree node is the inline context of the probes. The emission happens on the whole tree top-down recursively. Probes of a tree node will be emitted altogether with their direct parent edge. Since a pseudo probe corresponds to a real code address, for size savings, the address is encoded as a delta from the previous probe except for the first probe. Variant-sized integer encoding, aka LEB128, is used for address delta and probe index.
**Assembling**
Pseudo probes can be printed as assembly directives alternatively. This allows for good assembly code readability and also provides a view of how optimizations and pseudo probes affect each other, especially helpful for diff time assembly analysis.
A pseudo probe directive has the following operands in order: function GUID, probe index, probe type, probe attributes and inline context. The directive is generated by the compiler and can be parsed by the assembler to form an encoded `.pseudoprobe` section in the object file.
A example assembly looks like:
```
foo2: # @foo2
# %bb.0: # %bb0
pushq %rax
testl %edi, %edi
.pseudoprobe 837061429793323041 1 0 0
je .LBB1_1
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 6 2 0
callq foo
.pseudoprobe 837061429793323041 3 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
.LBB1_1: # %bb1
.pseudoprobe 837061429793323041 5 1 0
callq *%rsi
.pseudoprobe 837061429793323041 2 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
# -- End function
.section .pseudo_probe_desc,"",@progbits
.quad 6699318081062747564
.quad 72617220756
.byte 3
.ascii "foo"
.quad 837061429793323041
.quad 281547593931412
.byte 4
.ascii "foo2"
```
With inlining turned on, the assembly may look different around %bb2 with an inlined probe:
```
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 3 0
.pseudoprobe 6699318081062747564 1 0 @ 837061429793323041:6
.pseudoprobe 837061429793323041 4 0
popq %rax
retq
```
**Disassembling**
We have a disassembling tool (llvm-profgen) that can display disassembly alongside with pseudo probes. So far it only supports ELF executable file.
An example disassembly looks like:
```
00000000002011a0 <foo2>:
2011a0: 50 push rax
2011a1: 85 ff test edi,edi
[Probe]: FUNC: foo2 Index: 1 Type: Block
2011a3: 74 02 je 2011a7 <foo2+0x7>
[Probe]: FUNC: foo2 Index: 3 Type: Block
[Probe]: FUNC: foo2 Index: 4 Type: Block
[Probe]: FUNC: foo Index: 1 Type: Block Inlined: @ foo2:6
2011a5: 58 pop rax
2011a6: c3 ret
[Probe]: FUNC: foo2 Index: 2 Type: Block
2011a7: bf 01 00 00 00 mov edi,0x1
[Probe]: FUNC: foo2 Index: 5 Type: IndirectCall
2011ac: ff d6 call rsi
[Probe]: FUNC: foo2 Index: 4 Type: Block
2011ae: 58 pop rax
2011af: c3 ret
```
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D91878
2020-12-09 07:37:32 +08:00
|
|
|
|
|
|
|
PseudoProbeSection = Ctx->getELFSection(".pseudo_probe", DebugSecType, 0);
|
|
|
|
PseudoProbeDescSection =
|
|
|
|
Ctx->getELFSection(".pseudo_probe_desc", DebugSecType, 0);
|
2017-11-30 20:43:25 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) {
|
2018-12-04 04:02:05 +08:00
|
|
|
EHFrameSection =
|
|
|
|
Ctx->getCOFFSection(".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getData());
|
2017-11-30 20:43:25 +08:00
|
|
|
|
|
|
|
// Set the `IMAGE_SCN_MEM_16BIT` flag when compiling for thumb mode. This is
|
|
|
|
// used to indicate to the linker that the text segment contains thumb instructions
|
|
|
|
// and to set the ISA selection bit for calls accordingly.
|
|
|
|
const bool IsThumb = T.getArch() == Triple::thumb;
|
|
|
|
|
|
|
|
CommDirectiveSupportsAlignment = true;
|
|
|
|
|
|
|
|
// COFF
|
|
|
|
BSSSection = Ctx->getCOFFSection(
|
|
|
|
".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
|
|
|
|
SectionKind::getBSS());
|
|
|
|
TextSection = Ctx->getCOFFSection(
|
|
|
|
".text",
|
|
|
|
(IsThumb ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
|
|
|
|
COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getText());
|
|
|
|
DataSection = Ctx->getCOFFSection(
|
|
|
|
".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
|
|
|
|
COFF::IMAGE_SCN_MEM_WRITE,
|
|
|
|
SectionKind::getData());
|
|
|
|
ReadOnlySection = Ctx->getCOFFSection(
|
|
|
|
".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getReadOnly());
|
|
|
|
|
2018-12-18 16:32:37 +08:00
|
|
|
if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::aarch64) {
|
2017-11-30 20:43:25 +08:00
|
|
|
// On Windows 64 with SEH, the LSDA is emitted into the .xdata section
|
|
|
|
LSDASection = nullptr;
|
|
|
|
} else {
|
|
|
|
LSDASection = Ctx->getCOFFSection(".gcc_except_table",
|
|
|
|
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getReadOnly());
|
|
|
|
}
|
|
|
|
|
|
|
|
// Debug info.
|
|
|
|
COFFDebugSymbolsSection =
|
|
|
|
Ctx->getCOFFSection(".debug$S", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
|
|
|
|
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ),
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
COFFDebugTypesSection =
|
|
|
|
Ctx->getCOFFSection(".debug$T", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
|
|
|
|
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ),
|
|
|
|
SectionKind::getMetadata());
|
2017-12-14 06:33:58 +08:00
|
|
|
COFFGlobalTypeHashesSection = Ctx->getCOFFSection(
|
|
|
|
".debug$H",
|
|
|
|
(COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ),
|
|
|
|
SectionKind::getMetadata());
|
2017-11-30 20:43:25 +08:00
|
|
|
|
|
|
|
DwarfAbbrevSection = Ctx->getCOFFSection(
|
|
|
|
".debug_abbrev",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_abbrev");
|
|
|
|
DwarfInfoSection = Ctx->getCOFFSection(
|
|
|
|
".debug_info",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_info");
|
|
|
|
DwarfLineSection = Ctx->getCOFFSection(
|
|
|
|
".debug_line",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_line");
|
2018-02-07 04:29:21 +08:00
|
|
|
DwarfLineStrSection = Ctx->getCOFFSection(
|
|
|
|
".debug_line_str",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_line_str");
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfFrameSection = Ctx->getCOFFSection(
|
|
|
|
".debug_frame",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
DwarfPubNamesSection = Ctx->getCOFFSection(
|
|
|
|
".debug_pubnames",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
DwarfPubTypesSection = Ctx->getCOFFSection(
|
|
|
|
".debug_pubtypes",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
DwarfGnuPubNamesSection = Ctx->getCOFFSection(
|
|
|
|
".debug_gnu_pubnames",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
DwarfGnuPubTypesSection = Ctx->getCOFFSection(
|
|
|
|
".debug_gnu_pubtypes",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
DwarfStrSection = Ctx->getCOFFSection(
|
|
|
|
".debug_str",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "info_string");
|
|
|
|
DwarfStrOffSection = Ctx->getCOFFSection(
|
|
|
|
".debug_str_offsets",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_str_off");
|
|
|
|
DwarfLocSection = Ctx->getCOFFSection(
|
|
|
|
".debug_loc",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_debug_loc");
|
2020-02-05 11:23:57 +08:00
|
|
|
DwarfLoclistsSection = Ctx->getCOFFSection(
|
|
|
|
".debug_loclists",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_debug_loclists");
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfARangesSection = Ctx->getCOFFSection(
|
|
|
|
".debug_aranges",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
DwarfRangesSection = Ctx->getCOFFSection(
|
|
|
|
".debug_ranges",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "debug_range");
|
2020-02-05 11:23:57 +08:00
|
|
|
DwarfRnglistsSection = Ctx->getCOFFSection(
|
|
|
|
".debug_rnglists",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "debug_rnglists");
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfMacinfoSection = Ctx->getCOFFSection(
|
|
|
|
".debug_macinfo",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "debug_macinfo");
|
2020-04-03 15:14:09 +08:00
|
|
|
DwarfMacroSection = Ctx->getCOFFSection(
|
|
|
|
".debug_macro",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "debug_macro");
|
2019-12-04 21:02:39 +08:00
|
|
|
DwarfMacinfoDWOSection = Ctx->getCOFFSection(
|
|
|
|
".debug_macinfo.dwo",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "debug_macinfo.dwo");
|
2020-05-30 13:41:09 +08:00
|
|
|
DwarfMacroDWOSection = Ctx->getCOFFSection(
|
|
|
|
".debug_macro.dwo",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "debug_macro.dwo");
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfInfoDWOSection = Ctx->getCOFFSection(
|
|
|
|
".debug_info.dwo",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_info_dwo");
|
|
|
|
DwarfTypesDWOSection = Ctx->getCOFFSection(
|
|
|
|
".debug_types.dwo",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_types_dwo");
|
|
|
|
DwarfAbbrevDWOSection = Ctx->getCOFFSection(
|
|
|
|
".debug_abbrev.dwo",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_abbrev_dwo");
|
|
|
|
DwarfStrDWOSection = Ctx->getCOFFSection(
|
|
|
|
".debug_str.dwo",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "skel_string");
|
|
|
|
DwarfLineDWOSection = Ctx->getCOFFSection(
|
|
|
|
".debug_line.dwo",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
DwarfLocDWOSection = Ctx->getCOFFSection(
|
|
|
|
".debug_loc.dwo",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "skel_loc");
|
|
|
|
DwarfStrOffDWOSection = Ctx->getCOFFSection(
|
|
|
|
".debug_str_offsets.dwo",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "section_str_off_dwo");
|
|
|
|
DwarfAddrSection = Ctx->getCOFFSection(
|
|
|
|
".debug_addr",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "addr_sec");
|
|
|
|
DwarfCUIndexSection = Ctx->getCOFFSection(
|
|
|
|
".debug_cu_index",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
DwarfTUIndexSection = Ctx->getCOFFSection(
|
|
|
|
".debug_tu_index",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
2018-04-04 22:42:14 +08:00
|
|
|
DwarfDebugNamesSection = Ctx->getCOFFSection(
|
|
|
|
".debug_names",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "debug_names_begin");
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfAccelNamesSection = Ctx->getCOFFSection(
|
|
|
|
".apple_names",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "names_begin");
|
|
|
|
DwarfAccelNamespaceSection = Ctx->getCOFFSection(
|
|
|
|
".apple_namespaces",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "namespac_begin");
|
|
|
|
DwarfAccelTypesSection = Ctx->getCOFFSection(
|
|
|
|
".apple_types",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "types_begin");
|
|
|
|
DwarfAccelObjCSection = Ctx->getCOFFSection(
|
|
|
|
".apple_objc",
|
|
|
|
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata(), "objc_begin");
|
|
|
|
|
|
|
|
DrectveSection = Ctx->getCOFFSection(
|
|
|
|
".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
|
|
|
|
PDataSection = Ctx->getCOFFSection(
|
|
|
|
".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getData());
|
|
|
|
|
|
|
|
XDataSection = Ctx->getCOFFSection(
|
|
|
|
".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getData());
|
|
|
|
|
|
|
|
SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
|
2021-02-15 09:23:40 +08:00
|
|
|
GEHContSection = Ctx->getCOFFSection(".gehcont$y",
|
|
|
|
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
|
2018-01-10 07:49:30 +08:00
|
|
|
GFIDsSection = Ctx->getCOFFSection(".gfids$y",
|
|
|
|
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
Add Windows Control Flow Guard checks (/guard:cf).
Summary:
A new function pass (Transforms/CFGuard/CFGuard.cpp) inserts CFGuard checks on
indirect function calls, using either the check mechanism (X86, ARM, AArch64) or
or the dispatch mechanism (X86-64). The check mechanism requires a new calling
convention for the supported targets. The dispatch mechanism adds the target as
an operand bundle, which is processed by SelectionDAG. Another pass
(CodeGen/CFGuardLongjmp.cpp) identifies and emits valid longjmp targets, as
required by /guard:cf. This feature is enabled using the `cfguard` CC1 option.
Reviewers: thakis, rnk, theraven, pcc
Subscribers: ychen, hans, metalcanine, dmajor, tomrittervg, alex, mehdi_amini, mgorny, javed.absar, kristof.beyls, hiraditya, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D65761
2019-10-28 21:22:19 +08:00
|
|
|
|
2020-11-18 10:02:13 +08:00
|
|
|
GIATsSection = Ctx->getCOFFSection(".giats$y",
|
|
|
|
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
|
|
|
|
Add Windows Control Flow Guard checks (/guard:cf).
Summary:
A new function pass (Transforms/CFGuard/CFGuard.cpp) inserts CFGuard checks on
indirect function calls, using either the check mechanism (X86, ARM, AArch64) or
or the dispatch mechanism (X86-64). The check mechanism requires a new calling
convention for the supported targets. The dispatch mechanism adds the target as
an operand bundle, which is processed by SelectionDAG. Another pass
(CodeGen/CFGuardLongjmp.cpp) identifies and emits valid longjmp targets, as
required by /guard:cf. This feature is enabled using the `cfguard` CC1 option.
Reviewers: thakis, rnk, theraven, pcc
Subscribers: ychen, hans, metalcanine, dmajor, tomrittervg, alex, mehdi_amini, mgorny, javed.absar, kristof.beyls, hiraditya, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D65761
2019-10-28 21:22:19 +08:00
|
|
|
GLJMPSection = Ctx->getCOFFSection(".gljmp$y",
|
|
|
|
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getMetadata());
|
2018-01-10 07:49:30 +08:00
|
|
|
|
2017-11-30 20:43:25 +08:00
|
|
|
TLSDataSection = Ctx->getCOFFSection(
|
|
|
|
".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
|
|
|
|
COFF::IMAGE_SCN_MEM_WRITE,
|
|
|
|
SectionKind::getData());
|
|
|
|
|
|
|
|
StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
|
|
|
|
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
|
|
|
|
COFF::IMAGE_SCN_MEM_READ,
|
|
|
|
SectionKind::getReadOnly());
|
|
|
|
}
|
|
|
|
|
|
|
|
void MCObjectFileInfo::initWasmMCObjectFileInfo(const Triple &T) {
|
|
|
|
TextSection = Ctx->getWasmSection(".text", SectionKind::getText());
|
|
|
|
DataSection = Ctx->getWasmSection(".data", SectionKind::getData());
|
|
|
|
|
2018-05-11 01:38:35 +08:00
|
|
|
DwarfLineSection =
|
|
|
|
Ctx->getWasmSection(".debug_line", SectionKind::getMetadata());
|
2018-02-07 04:29:21 +08:00
|
|
|
DwarfLineStrSection =
|
|
|
|
Ctx->getWasmSection(".debug_line_str", SectionKind::getMetadata());
|
2018-05-11 01:38:35 +08:00
|
|
|
DwarfStrSection =
|
|
|
|
Ctx->getWasmSection(".debug_str", SectionKind::getMetadata());
|
|
|
|
DwarfLocSection =
|
|
|
|
Ctx->getWasmSection(".debug_loc", SectionKind::getMetadata());
|
|
|
|
DwarfAbbrevSection =
|
|
|
|
Ctx->getWasmSection(".debug_abbrev", SectionKind::getMetadata());
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfARangesSection = Ctx->getWasmSection(".debug_aranges", SectionKind::getMetadata());
|
2018-05-11 01:38:35 +08:00
|
|
|
DwarfRangesSection =
|
|
|
|
Ctx->getWasmSection(".debug_ranges", SectionKind::getMetadata());
|
|
|
|
DwarfMacinfoSection =
|
|
|
|
Ctx->getWasmSection(".debug_macinfo", SectionKind::getMetadata());
|
2020-04-03 15:14:09 +08:00
|
|
|
DwarfMacroSection =
|
|
|
|
Ctx->getWasmSection(".debug_macro", SectionKind::getMetadata());
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfCUIndexSection = Ctx->getWasmSection(".debug_cu_index", SectionKind::getMetadata());
|
|
|
|
DwarfTUIndexSection = Ctx->getWasmSection(".debug_tu_index", SectionKind::getMetadata());
|
2018-05-11 01:38:35 +08:00
|
|
|
DwarfInfoSection =
|
|
|
|
Ctx->getWasmSection(".debug_info", SectionKind::getMetadata());
|
2017-11-30 20:43:25 +08:00
|
|
|
DwarfFrameSection = Ctx->getWasmSection(".debug_frame", SectionKind::getMetadata());
|
|
|
|
DwarfPubNamesSection = Ctx->getWasmSection(".debug_pubnames", SectionKind::getMetadata());
|
|
|
|
DwarfPubTypesSection = Ctx->getWasmSection(".debug_pubtypes", SectionKind::getMetadata());
|
2020-08-08 12:23:11 +08:00
|
|
|
DwarfGnuPubNamesSection =
|
|
|
|
Ctx->getWasmSection(".debug_gnu_pubnames", SectionKind::getMetadata());
|
|
|
|
DwarfGnuPubTypesSection =
|
|
|
|
Ctx->getWasmSection(".debug_gnu_pubtypes", SectionKind::getMetadata());
|
2017-11-30 20:43:25 +08:00
|
|
|
|
2020-02-15 07:29:32 +08:00
|
|
|
DwarfDebugNamesSection =
|
|
|
|
Ctx->getWasmSection(".debug_names", SectionKind::getMetadata());
|
|
|
|
DwarfStrOffSection =
|
|
|
|
Ctx->getWasmSection(".debug_str_offsets", SectionKind::getMetadata());
|
|
|
|
DwarfAddrSection =
|
|
|
|
Ctx->getWasmSection(".debug_addr", SectionKind::getMetadata());
|
|
|
|
DwarfRnglistsSection =
|
|
|
|
Ctx->getWasmSection(".debug_rnglists", SectionKind::getMetadata());
|
|
|
|
DwarfLoclistsSection =
|
|
|
|
Ctx->getWasmSection(".debug_loclists", SectionKind::getMetadata());
|
|
|
|
|
2020-08-08 12:23:11 +08:00
|
|
|
// Fission Sections
|
|
|
|
DwarfInfoDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_info.dwo", SectionKind::getMetadata());
|
|
|
|
DwarfTypesDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_types.dwo", SectionKind::getMetadata());
|
|
|
|
DwarfAbbrevDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_abbrev.dwo", SectionKind::getMetadata());
|
|
|
|
DwarfStrDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_str.dwo", SectionKind::getMetadata());
|
|
|
|
DwarfLineDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_line.dwo", SectionKind::getMetadata());
|
|
|
|
DwarfLocDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_loc.dwo", SectionKind::getMetadata());
|
|
|
|
DwarfStrOffDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_str_offsets.dwo", SectionKind::getMetadata());
|
|
|
|
DwarfRnglistsDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_rnglists.dwo", SectionKind::getMetadata());
|
|
|
|
DwarfMacinfoDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_macinfo.dwo", SectionKind::getMetadata());
|
|
|
|
DwarfMacroDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_macro.dwo", SectionKind::getMetadata());
|
|
|
|
|
|
|
|
DwarfLoclistsDWOSection =
|
|
|
|
Ctx->getWasmSection(".debug_loclists.dwo", SectionKind::getMetadata());
|
|
|
|
|
|
|
|
// DWP Sections
|
|
|
|
DwarfCUIndexSection =
|
2021-02-27 08:09:32 +08:00
|
|
|
Ctx->getWasmSection(".debug_cu_index", SectionKind::getMetadata());
|
2020-08-08 12:23:11 +08:00
|
|
|
DwarfTUIndexSection =
|
2021-02-27 08:09:32 +08:00
|
|
|
Ctx->getWasmSection(".debug_tu_index", SectionKind::getMetadata());
|
2020-08-08 12:23:11 +08:00
|
|
|
|
Reland "[WebAssembly] LSDA info generation"
Summary:
This adds support for LSDA (exception table) generation for wasm EH.
Wasm EH mostly follows the structure of Itanium-style exception tables,
with one exception: a call site table entry in wasm EH corresponds to
not a call site but a landing pad.
In wasm EH, the VM is responsible for stack unwinding. After an
exception occurs and the stack is unwound, the control flow is
transferred to wasm 'catch' instruction by the VM, after which the
personality function is called from the compiler-generated code. (Refer
to WasmEHPrepare pass for more information on this part.)
This patch:
- Changes wasm.landingpad.index intrinsic to take a token argument, to
make this 1:1 match with a catchpad instruction
- Stores landingpad index info and catch type info MachineFunction in
before instruction selection
- Lowers wasm.lsda intrinsic to an MCSymbol pointing to the start of an
exception table
- Adds WasmException class with overridden methods for table generation
- Adds support for LSDA section in Wasm object writer
Reviewers: dschuff, sbc100, rnk
Subscribers: mgorny, jgravelle-google, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D52748
llvm-svn: 345345
2018-10-26 07:55:10 +08:00
|
|
|
// Wasm use data section for LSDA.
|
|
|
|
// TODO Consider putting each function's exception table in a separate
|
|
|
|
// section, as in -function-sections, to facilitate lld's --gc-section.
|
|
|
|
LSDASection = Ctx->getWasmSection(".rodata.gcc_except_table",
|
|
|
|
SectionKind::getReadOnlyWithRel());
|
|
|
|
|
2017-11-30 20:43:25 +08:00
|
|
|
// TODO: Define more sections.
|
|
|
|
}
|
|
|
|
|
2019-07-10 03:21:01 +08:00
|
|
|
void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
|
|
|
|
// The default csect for program code. Functions without a specified section
|
|
|
|
// get placed into this csect. The choice of csect name is not a property of
|
|
|
|
// the ABI or object file format. For example, the XL compiler uses an unnamed
|
|
|
|
// csect for program code.
|
2020-11-09 23:12:46 +08:00
|
|
|
TextSection = Ctx->getXCOFFSection(
|
2021-02-18 09:42:45 +08:00
|
|
|
".text", SectionKind::getText(),
|
|
|
|
XCOFF::CsectProperties(XCOFF::StorageMappingClass::XMC_PR, XCOFF::XTY_SD),
|
|
|
|
/* MultiSymbolsAllowed*/ true);
|
[PowerPC][AIX] Adds support for writing the .data section in assembly files
Summary:
Adds support for generating the .data section in assembly files for global variables with a non-zero initialization. The support for writing the .data section in XCOFF object files will be added in a follow-on patch. Any relocations are not included in this patch.
Reviewers: hubert.reinterpretcast, sfertile, jasonliu, daltenty, Xiangling_L
Reviewed by: hubert.reinterpretcast
Subscribers: nemanjai, hiraditya, kbarton, MaskRay, jsji, wuzish, shchenz, DiggerLin, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66154
llvm-svn: 369869
2019-08-25 23:17:25 +08:00
|
|
|
|
2020-11-09 23:12:46 +08:00
|
|
|
DataSection = Ctx->getXCOFFSection(
|
2021-02-18 09:42:45 +08:00
|
|
|
".data", SectionKind::getData(),
|
|
|
|
XCOFF::CsectProperties(XCOFF::StorageMappingClass::XMC_RW, XCOFF::XTY_SD),
|
|
|
|
/* MultiSymbolsAllowed*/ true);
|
2019-11-16 00:30:19 +08:00
|
|
|
|
2020-11-09 23:12:46 +08:00
|
|
|
ReadOnlySection = Ctx->getXCOFFSection(
|
2021-02-18 09:42:45 +08:00
|
|
|
".rodata", SectionKind::getReadOnly(),
|
|
|
|
XCOFF::CsectProperties(XCOFF::StorageMappingClass::XMC_RO, XCOFF::XTY_SD),
|
|
|
|
/* MultiSymbolsAllowed*/ true);
|
[NFC][XCOFF] Refactor Csect creation into TargetLoweringObjectFile
Summary:
We create a number of standard types of control sections in multiple places for
things like the function descriptors, external references and the TOC anchor
among others, so it is possible for their properties to be defined
inconsistently in different places. This refactor moves their creation and
properties into functions in the TargetLoweringObjectFile class hierarchy, where
functions for retrieving various special types of sections typically seem
to reside.
Note: There is one case in PPCISelLowering which is specific to function entry
points which we don't address since we don't have access to the TLOF there.
Reviewers: DiggerLin, jasonliu, hubert.reinterpretcast
Reviewed By: jasonliu, hubert.reinterpretcast
Subscribers: wuzish, nemanjai, hiraditya, kbarton, jsji, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72347
2020-01-23 00:09:34 +08:00
|
|
|
|
2021-03-03 08:16:14 +08:00
|
|
|
TLSDataSection = Ctx->getXCOFFSection(
|
|
|
|
".tdata", SectionKind::getThreadData(),
|
|
|
|
XCOFF::CsectProperties(XCOFF::StorageMappingClass::XMC_TL, XCOFF::XTY_SD),
|
|
|
|
/* MultiSymbolsAllowed*/ true);
|
|
|
|
|
2021-02-18 09:42:45 +08:00
|
|
|
TOCBaseSection = Ctx->getXCOFFSection(
|
|
|
|
"TOC", SectionKind::getData(),
|
|
|
|
XCOFF::CsectProperties(XCOFF::StorageMappingClass::XMC_TC0,
|
|
|
|
XCOFF::XTY_SD));
|
[NFC][XCOFF] Refactor Csect creation into TargetLoweringObjectFile
Summary:
We create a number of standard types of control sections in multiple places for
things like the function descriptors, external references and the TOC anchor
among others, so it is possible for their properties to be defined
inconsistently in different places. This refactor moves their creation and
properties into functions in the TargetLoweringObjectFile class hierarchy, where
functions for retrieving various special types of sections typically seem
to reside.
Note: There is one case in PPCISelLowering which is specific to function entry
points which we don't address since we don't have access to the TLOF there.
Reviewers: DiggerLin, jasonliu, hubert.reinterpretcast
Reviewed By: jasonliu, hubert.reinterpretcast
Subscribers: wuzish, nemanjai, hiraditya, kbarton, jsji, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72347
2020-01-23 00:09:34 +08:00
|
|
|
|
|
|
|
// The TOC-base always has 0 size, but 4 byte alignment.
|
|
|
|
TOCBaseSection->setAlignment(Align(4));
|
2020-05-09 04:32:12 +08:00
|
|
|
|
2021-02-18 09:42:45 +08:00
|
|
|
LSDASection = Ctx->getXCOFFSection(
|
|
|
|
".gcc_except_table", SectionKind::getReadOnly(),
|
|
|
|
XCOFF::CsectProperties(XCOFF::StorageMappingClass::XMC_RO,
|
|
|
|
XCOFF::XTY_SD));
|
2020-12-02 22:48:52 +08:00
|
|
|
|
2021-02-18 09:42:45 +08:00
|
|
|
CompactUnwindSection = Ctx->getXCOFFSection(
|
|
|
|
".eh_info_table", SectionKind::getData(),
|
|
|
|
XCOFF::CsectProperties(XCOFF::StorageMappingClass::XMC_RW,
|
|
|
|
XCOFF::XTY_SD));
|
2020-12-02 22:48:52 +08:00
|
|
|
|
2020-05-09 04:32:12 +08:00
|
|
|
// DWARF sections for XCOFF are not csects. They are special STYP_DWARF
|
|
|
|
// sections, and the individual DWARF sections are distinguished by their
|
|
|
|
// section subtype.
|
2021-03-05 09:47:41 +08:00
|
|
|
DwarfAbbrevSection = Ctx->getXCOFFSection(
|
|
|
|
".dwabrev", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwabrev", XCOFF::SSUBTYP_DWABREV);
|
|
|
|
|
|
|
|
DwarfInfoSection = Ctx->getXCOFFSection(
|
|
|
|
".dwinfo", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwinfo", XCOFF::SSUBTYP_DWINFO);
|
|
|
|
|
|
|
|
DwarfLineSection = Ctx->getXCOFFSection(
|
|
|
|
".dwline", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwline", XCOFF::SSUBTYP_DWLINE);
|
|
|
|
|
|
|
|
DwarfFrameSection = Ctx->getXCOFFSection(
|
|
|
|
".dwframe", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwframe", XCOFF::SSUBTYP_DWFRAME);
|
|
|
|
|
|
|
|
DwarfPubNamesSection = Ctx->getXCOFFSection(
|
|
|
|
".dwpbnms", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwpbnms", XCOFF::SSUBTYP_DWPBNMS);
|
|
|
|
|
|
|
|
DwarfPubTypesSection = Ctx->getXCOFFSection(
|
|
|
|
".dwpbtyp", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwpbtyp", XCOFF::SSUBTYP_DWPBTYP);
|
|
|
|
|
|
|
|
DwarfStrSection = Ctx->getXCOFFSection(
|
|
|
|
".dwstr", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwstr", XCOFF::SSUBTYP_DWSTR);
|
|
|
|
|
|
|
|
DwarfLocSection = Ctx->getXCOFFSection(
|
|
|
|
".dwloc", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwloc", XCOFF::SSUBTYP_DWLOC);
|
|
|
|
|
|
|
|
DwarfARangesSection = Ctx->getXCOFFSection(
|
|
|
|
".dwarnge", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwarnge", XCOFF::SSUBTYP_DWARNGE);
|
|
|
|
|
|
|
|
DwarfRangesSection = Ctx->getXCOFFSection(
|
|
|
|
".dwrnges", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwrnges", XCOFF::SSUBTYP_DWRNGES);
|
|
|
|
|
|
|
|
DwarfMacinfoSection = Ctx->getXCOFFSection(
|
|
|
|
".dwmac", SectionKind::getMetadata(), /* CsectProperties */ None,
|
|
|
|
/* MultiSymbolsAllowed */ true, ".dwmac", XCOFF::SSUBTYP_DWMAC);
|
2019-07-10 03:21:01 +08:00
|
|
|
}
|
|
|
|
|
2021-05-06 01:03:02 +08:00
|
|
|
void MCObjectFileInfo::initMCObjectFileInfo(MCContext &MCCtx, bool PIC,
|
2017-11-30 20:43:25 +08:00
|
|
|
bool LargeCodeModel) {
|
|
|
|
PositionIndependent = PIC;
|
2021-05-06 01:03:02 +08:00
|
|
|
Ctx = &MCCtx;
|
2017-11-30 20:43:25 +08:00
|
|
|
|
|
|
|
// Common.
|
|
|
|
CommDirectiveSupportsAlignment = true;
|
|
|
|
SupportsWeakOmittedEHFrame = true;
|
|
|
|
SupportsCompactUnwindWithoutEHFrame = false;
|
|
|
|
OmitDwarfIfHaveCompactUnwind = false;
|
|
|
|
|
[MC] Move EH DWARF encodings from MC to CodeGen, NFC
Summary:
The TType encoding, LSDA encoding, and personality encoding are all
passed explicitly by CodeGen to the assembler through .cfi_* directives,
so only the AsmPrinter needs to know about them.
The FDE CFI encoding however, controls the encoding of the label
implicitly created by the .cfi_startproc directive. That directive seems
to be special in that it doesn't take an encoding, so the assembler just
has to know how to encode one DSO-local label reference from .eh_frame
to .text.
As a result, it looks like MC will continue to have to know when the
large code model is in use. Perhaps we could invent a '.cfi_startproc
[large]' flag so that this knowledge doesn't need to pollute the
assembler.
Reviewers: davide, lliu0, JDevlieghere
Subscribers: hiraditya, fedor.sergeev, llvm-commits
Differential Revision: https://reviews.llvm.org/D50533
llvm-svn: 339397
2018-08-10 06:24:04 +08:00
|
|
|
FDECFIEncoding = dwarf::DW_EH_PE_absptr;
|
2017-11-30 20:43:25 +08:00
|
|
|
|
|
|
|
CompactUnwindDwarfEHFrameOnly = 0;
|
|
|
|
|
|
|
|
EHFrameSection = nullptr; // Created on demand.
|
|
|
|
CompactUnwindSection = nullptr; // Used only by selected targets.
|
|
|
|
DwarfAccelNamesSection = nullptr; // Used only by selected targets.
|
|
|
|
DwarfAccelObjCSection = nullptr; // Used only by selected targets.
|
|
|
|
DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
|
|
|
|
DwarfAccelTypesSection = nullptr; // Used only by selected targets.
|
|
|
|
|
2021-05-06 01:03:02 +08:00
|
|
|
Triple TheTriple = Ctx->getTargetTriple();
|
|
|
|
switch (Ctx->getObjectFileType()) {
|
|
|
|
case MCContext::IsMachO:
|
|
|
|
initMachOMCObjectFileInfo(TheTriple);
|
2017-11-30 20:43:25 +08:00
|
|
|
break;
|
2021-05-06 01:03:02 +08:00
|
|
|
case MCContext::IsCOFF:
|
|
|
|
initCOFFMCObjectFileInfo(TheTriple);
|
2017-11-30 20:43:25 +08:00
|
|
|
break;
|
2021-05-06 01:03:02 +08:00
|
|
|
case MCContext::IsELF:
|
|
|
|
initELFMCObjectFileInfo(TheTriple, LargeCodeModel);
|
2017-11-30 20:43:25 +08:00
|
|
|
break;
|
2021-05-06 01:03:02 +08:00
|
|
|
case MCContext::IsWasm:
|
|
|
|
initWasmMCObjectFileInfo(TheTriple);
|
2017-11-30 20:43:25 +08:00
|
|
|
break;
|
2021-05-06 01:03:02 +08:00
|
|
|
case MCContext::IsXCOFF:
|
|
|
|
initXCOFFMCObjectFileInfo(TheTriple);
|
2017-11-30 20:43:25 +08:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2018-11-10 03:06:09 +08:00
|
|
|
MCSection *MCObjectFileInfo::getDwarfComdatSection(const char *Name,
|
|
|
|
uint64_t Hash) const {
|
2021-05-06 01:03:02 +08:00
|
|
|
switch (Ctx->getTargetTriple().getObjectFormat()) {
|
2018-08-01 20:53:06 +08:00
|
|
|
case Triple::ELF:
|
2018-11-10 03:06:09 +08:00
|
|
|
return Ctx->getELFSection(Name, ELF::SHT_PROGBITS, ELF::SHF_GROUP, 0,
|
2021-02-01 14:42:35 +08:00
|
|
|
utostr(Hash), /*IsComdat=*/true);
|
2020-10-29 08:15:58 +08:00
|
|
|
case Triple::Wasm:
|
2021-02-27 08:09:32 +08:00
|
|
|
return Ctx->getWasmSection(Name, SectionKind::getMetadata(), 0,
|
|
|
|
utostr(Hash), MCContext::GenericSectionID);
|
2018-08-01 20:53:06 +08:00
|
|
|
case Triple::MachO:
|
|
|
|
case Triple::COFF:
|
2020-06-19 19:43:35 +08:00
|
|
|
case Triple::GOFF:
|
2019-03-13 06:01:10 +08:00
|
|
|
case Triple::XCOFF:
|
2018-08-01 20:53:06 +08:00
|
|
|
case Triple::UnknownObjectFormat:
|
2018-11-10 03:06:09 +08:00
|
|
|
report_fatal_error("Cannot get DWARF comdat section for this object file "
|
2018-08-01 20:53:06 +08:00
|
|
|
"format: not implemented.");
|
|
|
|
break;
|
|
|
|
}
|
2018-08-01 21:00:11 +08:00
|
|
|
llvm_unreachable("Unknown ObjectFormatType");
|
2017-11-30 20:43:25 +08:00
|
|
|
}
|
2018-06-22 18:53:47 +08:00
|
|
|
|
|
|
|
MCSection *
|
|
|
|
MCObjectFileInfo::getStackSizesSection(const MCSection &TextSec) const {
|
2021-05-06 01:03:02 +08:00
|
|
|
if (Ctx->getObjectFileType() != MCContext::IsELF)
|
2018-06-22 18:53:47 +08:00
|
|
|
return StackSizesSection;
|
|
|
|
|
|
|
|
const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
|
|
|
|
unsigned Flags = ELF::SHF_LINK_ORDER;
|
|
|
|
StringRef GroupName;
|
|
|
|
if (const MCSymbol *Group = ElfSec.getGroup()) {
|
|
|
|
GroupName = Group->getName();
|
|
|
|
Flags |= ELF::SHF_GROUP;
|
|
|
|
}
|
|
|
|
|
|
|
|
return Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, Flags, 0,
|
2021-02-01 14:42:35 +08:00
|
|
|
GroupName, true, ElfSec.getUniqueID(),
|
2020-02-15 13:14:31 +08:00
|
|
|
cast<MCSymbolELF>(TextSec.getBeginSymbol()));
|
2018-06-22 18:53:47 +08:00
|
|
|
}
|
2020-09-15 01:16:44 +08:00
|
|
|
|
|
|
|
MCSection *
|
|
|
|
MCObjectFileInfo::getBBAddrMapSection(const MCSection &TextSec) const {
|
2021-05-06 01:03:02 +08:00
|
|
|
if (Ctx->getObjectFileType() != MCContext::IsELF)
|
2020-09-15 01:16:44 +08:00
|
|
|
return nullptr;
|
|
|
|
|
|
|
|
const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
|
|
|
|
unsigned Flags = ELF::SHF_LINK_ORDER;
|
|
|
|
StringRef GroupName;
|
|
|
|
if (const MCSymbol *Group = ElfSec.getGroup()) {
|
|
|
|
GroupName = Group->getName();
|
|
|
|
Flags |= ELF::SHF_GROUP;
|
|
|
|
}
|
|
|
|
|
2020-12-02 01:20:34 +08:00
|
|
|
// Use the text section's begin symbol and unique ID to create a separate
|
|
|
|
// .llvm_bb_addr_map section associated with every unique text section.
|
2020-10-09 02:12:40 +08:00
|
|
|
return Ctx->getELFSection(".llvm_bb_addr_map", ELF::SHT_LLVM_BB_ADDR_MAP,
|
2021-02-01 14:42:35 +08:00
|
|
|
Flags, 0, GroupName, true, ElfSec.getUniqueID(),
|
2020-09-15 01:16:44 +08:00
|
|
|
cast<MCSymbolELF>(TextSec.getBeginSymbol()));
|
|
|
|
}
|
[CSSPGO] Pseudo probe encoding and emission.
This change implements pseudo probe encoding and emission for CSSPGO. Please see RFC here for more context: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s
Pseudo probes are in the form of intrinsic calls on IR/MIR but they do not turn into any machine instructions. Instead they are emitted into the binary as a piece of data in standalone sections. The probe-specific sections are not needed to be loaded into memory at execution time, thus they do not incur a runtime overhead.
**ELF object emission**
The binary data to emit are organized as two ELF sections, i.e, the `.pseudo_probe_desc` section and the `.pseudo_probe` section. The `.pseudo_probe_desc` section stores a function descriptor for each function and the `.pseudo_probe` section stores the actual probes, each fo which corresponds to an IR basic block or an IR function callsite. A function descriptor is stored as a module-level metadata during the compilation and is serialized into the object file during object emission.
Both the probe descriptors and pseudo probes can be emitted into a separate ELF section per function to leverage the linker for deduplication. A `.pseudo_probe` section shares the same COMDAT group with the function code so that when the function is dead, the probes are dead and disposed too. On the contrary, a `.pseudo_probe_desc` section has its own COMDAT group. This is because even if a function is dead, its probes may be inlined into other functions and its descriptor is still needed by the profile generation tool.
The format of `.pseudo_probe_desc` section looks like:
```
.section .pseudo_probe_desc,"",@progbits
.quad 6309742469962978389 // Func GUID
.quad 4294967295 // Func Hash
.byte 9 // Length of func name
.ascii "_Z5funcAi" // Func name
.quad 7102633082150537521
.quad 138828622701
.byte 12
.ascii "_Z8funcLeafi"
.quad 446061515086924981
.quad 4294967295
.byte 9
.ascii "_Z5funcBi"
.quad -2016976694713209516
.quad 72617220756
.byte 7
.ascii "_Z3fibi"
```
For each `.pseudoprobe` section, the encoded binary data consists of a single function record corresponding to an outlined function (i.e, a function with a code entry in the `.text` section). A function record has the following format :
```
FUNCTION BODY (one for each outlined function present in the text section)
GUID (uint64)
GUID of the function
NPROBES (ULEB128)
Number of probes originating from this function.
NUM_INLINED_FUNCTIONS (ULEB128)
Number of callees inlined into this function, aka number of
first-level inlinees
PROBE RECORDS
A list of NPROBES entries. Each entry contains:
INDEX (ULEB128)
TYPE (uint4)
0 - block probe, 1 - indirect call, 2 - direct call
ATTRIBUTE (uint3)
reserved
ADDRESS_TYPE (uint1)
0 - code address, 1 - address delta
CODE_ADDRESS (uint64 or ULEB128)
code address or address delta, depending on ADDRESS_TYPE
INLINED FUNCTION RECORDS
A list of NUM_INLINED_FUNCTIONS entries describing each of the inlined
callees. Each record contains:
INLINE SITE
GUID of the inlinee (uint64)
ID of the callsite probe (ULEB128)
FUNCTION BODY
A FUNCTION BODY entry describing the inlined function.
```
To support building a context-sensitive profile, probes from inlinees are grouped by their inline contexts. An inline context is logically a call path through which a callee function lands in a caller function. The probe emitter builds an inline tree based on the debug metadata for each outlined function in the form of a trie tree. A tree root is the outlined function. Each tree edge stands for a callsite where inlining happens. Pseudo probes originating from an inlinee function are stored in a tree node and the tree path starting from the root all the way down to the tree node is the inline context of the probes. The emission happens on the whole tree top-down recursively. Probes of a tree node will be emitted altogether with their direct parent edge. Since a pseudo probe corresponds to a real code address, for size savings, the address is encoded as a delta from the previous probe except for the first probe. Variant-sized integer encoding, aka LEB128, is used for address delta and probe index.
**Assembling**
Pseudo probes can be printed as assembly directives alternatively. This allows for good assembly code readability and also provides a view of how optimizations and pseudo probes affect each other, especially helpful for diff time assembly analysis.
A pseudo probe directive has the following operands in order: function GUID, probe index, probe type, probe attributes and inline context. The directive is generated by the compiler and can be parsed by the assembler to form an encoded `.pseudoprobe` section in the object file.
A example assembly looks like:
```
foo2: # @foo2
# %bb.0: # %bb0
pushq %rax
testl %edi, %edi
.pseudoprobe 837061429793323041 1 0 0
je .LBB1_1
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 6 2 0
callq foo
.pseudoprobe 837061429793323041 3 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
.LBB1_1: # %bb1
.pseudoprobe 837061429793323041 5 1 0
callq *%rsi
.pseudoprobe 837061429793323041 2 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
# -- End function
.section .pseudo_probe_desc,"",@progbits
.quad 6699318081062747564
.quad 72617220756
.byte 3
.ascii "foo"
.quad 837061429793323041
.quad 281547593931412
.byte 4
.ascii "foo2"
```
With inlining turned on, the assembly may look different around %bb2 with an inlined probe:
```
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 3 0
.pseudoprobe 6699318081062747564 1 0 @ 837061429793323041:6
.pseudoprobe 837061429793323041 4 0
popq %rax
retq
```
**Disassembling**
We have a disassembling tool (llvm-profgen) that can display disassembly alongside with pseudo probes. So far it only supports ELF executable file.
An example disassembly looks like:
```
00000000002011a0 <foo2>:
2011a0: 50 push rax
2011a1: 85 ff test edi,edi
[Probe]: FUNC: foo2 Index: 1 Type: Block
2011a3: 74 02 je 2011a7 <foo2+0x7>
[Probe]: FUNC: foo2 Index: 3 Type: Block
[Probe]: FUNC: foo2 Index: 4 Type: Block
[Probe]: FUNC: foo Index: 1 Type: Block Inlined: @ foo2:6
2011a5: 58 pop rax
2011a6: c3 ret
[Probe]: FUNC: foo2 Index: 2 Type: Block
2011a7: bf 01 00 00 00 mov edi,0x1
[Probe]: FUNC: foo2 Index: 5 Type: IndirectCall
2011ac: ff d6 call rsi
[Probe]: FUNC: foo2 Index: 4 Type: Block
2011ae: 58 pop rax
2011af: c3 ret
```
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D91878
2020-12-09 07:37:32 +08:00
|
|
|
|
|
|
|
MCSection *
|
|
|
|
MCObjectFileInfo::getPseudoProbeSection(const MCSection *TextSec) const {
|
2021-05-06 01:03:02 +08:00
|
|
|
if (Ctx->getObjectFileType() == MCContext::IsELF) {
|
[CSSPGO] Pseudo probe encoding and emission.
This change implements pseudo probe encoding and emission for CSSPGO. Please see RFC here for more context: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s
Pseudo probes are in the form of intrinsic calls on IR/MIR but they do not turn into any machine instructions. Instead they are emitted into the binary as a piece of data in standalone sections. The probe-specific sections are not needed to be loaded into memory at execution time, thus they do not incur a runtime overhead.
**ELF object emission**
The binary data to emit are organized as two ELF sections, i.e, the `.pseudo_probe_desc` section and the `.pseudo_probe` section. The `.pseudo_probe_desc` section stores a function descriptor for each function and the `.pseudo_probe` section stores the actual probes, each fo which corresponds to an IR basic block or an IR function callsite. A function descriptor is stored as a module-level metadata during the compilation and is serialized into the object file during object emission.
Both the probe descriptors and pseudo probes can be emitted into a separate ELF section per function to leverage the linker for deduplication. A `.pseudo_probe` section shares the same COMDAT group with the function code so that when the function is dead, the probes are dead and disposed too. On the contrary, a `.pseudo_probe_desc` section has its own COMDAT group. This is because even if a function is dead, its probes may be inlined into other functions and its descriptor is still needed by the profile generation tool.
The format of `.pseudo_probe_desc` section looks like:
```
.section .pseudo_probe_desc,"",@progbits
.quad 6309742469962978389 // Func GUID
.quad 4294967295 // Func Hash
.byte 9 // Length of func name
.ascii "_Z5funcAi" // Func name
.quad 7102633082150537521
.quad 138828622701
.byte 12
.ascii "_Z8funcLeafi"
.quad 446061515086924981
.quad 4294967295
.byte 9
.ascii "_Z5funcBi"
.quad -2016976694713209516
.quad 72617220756
.byte 7
.ascii "_Z3fibi"
```
For each `.pseudoprobe` section, the encoded binary data consists of a single function record corresponding to an outlined function (i.e, a function with a code entry in the `.text` section). A function record has the following format :
```
FUNCTION BODY (one for each outlined function present in the text section)
GUID (uint64)
GUID of the function
NPROBES (ULEB128)
Number of probes originating from this function.
NUM_INLINED_FUNCTIONS (ULEB128)
Number of callees inlined into this function, aka number of
first-level inlinees
PROBE RECORDS
A list of NPROBES entries. Each entry contains:
INDEX (ULEB128)
TYPE (uint4)
0 - block probe, 1 - indirect call, 2 - direct call
ATTRIBUTE (uint3)
reserved
ADDRESS_TYPE (uint1)
0 - code address, 1 - address delta
CODE_ADDRESS (uint64 or ULEB128)
code address or address delta, depending on ADDRESS_TYPE
INLINED FUNCTION RECORDS
A list of NUM_INLINED_FUNCTIONS entries describing each of the inlined
callees. Each record contains:
INLINE SITE
GUID of the inlinee (uint64)
ID of the callsite probe (ULEB128)
FUNCTION BODY
A FUNCTION BODY entry describing the inlined function.
```
To support building a context-sensitive profile, probes from inlinees are grouped by their inline contexts. An inline context is logically a call path through which a callee function lands in a caller function. The probe emitter builds an inline tree based on the debug metadata for each outlined function in the form of a trie tree. A tree root is the outlined function. Each tree edge stands for a callsite where inlining happens. Pseudo probes originating from an inlinee function are stored in a tree node and the tree path starting from the root all the way down to the tree node is the inline context of the probes. The emission happens on the whole tree top-down recursively. Probes of a tree node will be emitted altogether with their direct parent edge. Since a pseudo probe corresponds to a real code address, for size savings, the address is encoded as a delta from the previous probe except for the first probe. Variant-sized integer encoding, aka LEB128, is used for address delta and probe index.
**Assembling**
Pseudo probes can be printed as assembly directives alternatively. This allows for good assembly code readability and also provides a view of how optimizations and pseudo probes affect each other, especially helpful for diff time assembly analysis.
A pseudo probe directive has the following operands in order: function GUID, probe index, probe type, probe attributes and inline context. The directive is generated by the compiler and can be parsed by the assembler to form an encoded `.pseudoprobe` section in the object file.
A example assembly looks like:
```
foo2: # @foo2
# %bb.0: # %bb0
pushq %rax
testl %edi, %edi
.pseudoprobe 837061429793323041 1 0 0
je .LBB1_1
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 6 2 0
callq foo
.pseudoprobe 837061429793323041 3 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
.LBB1_1: # %bb1
.pseudoprobe 837061429793323041 5 1 0
callq *%rsi
.pseudoprobe 837061429793323041 2 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
# -- End function
.section .pseudo_probe_desc,"",@progbits
.quad 6699318081062747564
.quad 72617220756
.byte 3
.ascii "foo"
.quad 837061429793323041
.quad 281547593931412
.byte 4
.ascii "foo2"
```
With inlining turned on, the assembly may look different around %bb2 with an inlined probe:
```
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 3 0
.pseudoprobe 6699318081062747564 1 0 @ 837061429793323041:6
.pseudoprobe 837061429793323041 4 0
popq %rax
retq
```
**Disassembling**
We have a disassembling tool (llvm-profgen) that can display disassembly alongside with pseudo probes. So far it only supports ELF executable file.
An example disassembly looks like:
```
00000000002011a0 <foo2>:
2011a0: 50 push rax
2011a1: 85 ff test edi,edi
[Probe]: FUNC: foo2 Index: 1 Type: Block
2011a3: 74 02 je 2011a7 <foo2+0x7>
[Probe]: FUNC: foo2 Index: 3 Type: Block
[Probe]: FUNC: foo2 Index: 4 Type: Block
[Probe]: FUNC: foo Index: 1 Type: Block Inlined: @ foo2:6
2011a5: 58 pop rax
2011a6: c3 ret
[Probe]: FUNC: foo2 Index: 2 Type: Block
2011a7: bf 01 00 00 00 mov edi,0x1
[Probe]: FUNC: foo2 Index: 5 Type: IndirectCall
2011ac: ff d6 call rsi
[Probe]: FUNC: foo2 Index: 4 Type: Block
2011ae: 58 pop rax
2011af: c3 ret
```
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D91878
2020-12-09 07:37:32 +08:00
|
|
|
const auto *ElfSec = static_cast<const MCSectionELF *>(TextSec);
|
|
|
|
// Create a separate section for probes that comes with a comdat function.
|
|
|
|
if (const MCSymbol *Group = ElfSec->getGroup()) {
|
|
|
|
auto *S = static_cast<MCSectionELF *>(PseudoProbeSection);
|
|
|
|
auto Flags = S->getFlags() | ELF::SHF_GROUP;
|
|
|
|
return Ctx->getELFSection(S->getName(), S->getType(), Flags,
|
2021-02-01 14:42:35 +08:00
|
|
|
S->getEntrySize(), Group->getName(),
|
|
|
|
/*IsComdat=*/true);
|
[CSSPGO] Pseudo probe encoding and emission.
This change implements pseudo probe encoding and emission for CSSPGO. Please see RFC here for more context: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s
Pseudo probes are in the form of intrinsic calls on IR/MIR but they do not turn into any machine instructions. Instead they are emitted into the binary as a piece of data in standalone sections. The probe-specific sections are not needed to be loaded into memory at execution time, thus they do not incur a runtime overhead.
**ELF object emission**
The binary data to emit are organized as two ELF sections, i.e, the `.pseudo_probe_desc` section and the `.pseudo_probe` section. The `.pseudo_probe_desc` section stores a function descriptor for each function and the `.pseudo_probe` section stores the actual probes, each fo which corresponds to an IR basic block or an IR function callsite. A function descriptor is stored as a module-level metadata during the compilation and is serialized into the object file during object emission.
Both the probe descriptors and pseudo probes can be emitted into a separate ELF section per function to leverage the linker for deduplication. A `.pseudo_probe` section shares the same COMDAT group with the function code so that when the function is dead, the probes are dead and disposed too. On the contrary, a `.pseudo_probe_desc` section has its own COMDAT group. This is because even if a function is dead, its probes may be inlined into other functions and its descriptor is still needed by the profile generation tool.
The format of `.pseudo_probe_desc` section looks like:
```
.section .pseudo_probe_desc,"",@progbits
.quad 6309742469962978389 // Func GUID
.quad 4294967295 // Func Hash
.byte 9 // Length of func name
.ascii "_Z5funcAi" // Func name
.quad 7102633082150537521
.quad 138828622701
.byte 12
.ascii "_Z8funcLeafi"
.quad 446061515086924981
.quad 4294967295
.byte 9
.ascii "_Z5funcBi"
.quad -2016976694713209516
.quad 72617220756
.byte 7
.ascii "_Z3fibi"
```
For each `.pseudoprobe` section, the encoded binary data consists of a single function record corresponding to an outlined function (i.e, a function with a code entry in the `.text` section). A function record has the following format :
```
FUNCTION BODY (one for each outlined function present in the text section)
GUID (uint64)
GUID of the function
NPROBES (ULEB128)
Number of probes originating from this function.
NUM_INLINED_FUNCTIONS (ULEB128)
Number of callees inlined into this function, aka number of
first-level inlinees
PROBE RECORDS
A list of NPROBES entries. Each entry contains:
INDEX (ULEB128)
TYPE (uint4)
0 - block probe, 1 - indirect call, 2 - direct call
ATTRIBUTE (uint3)
reserved
ADDRESS_TYPE (uint1)
0 - code address, 1 - address delta
CODE_ADDRESS (uint64 or ULEB128)
code address or address delta, depending on ADDRESS_TYPE
INLINED FUNCTION RECORDS
A list of NUM_INLINED_FUNCTIONS entries describing each of the inlined
callees. Each record contains:
INLINE SITE
GUID of the inlinee (uint64)
ID of the callsite probe (ULEB128)
FUNCTION BODY
A FUNCTION BODY entry describing the inlined function.
```
To support building a context-sensitive profile, probes from inlinees are grouped by their inline contexts. An inline context is logically a call path through which a callee function lands in a caller function. The probe emitter builds an inline tree based on the debug metadata for each outlined function in the form of a trie tree. A tree root is the outlined function. Each tree edge stands for a callsite where inlining happens. Pseudo probes originating from an inlinee function are stored in a tree node and the tree path starting from the root all the way down to the tree node is the inline context of the probes. The emission happens on the whole tree top-down recursively. Probes of a tree node will be emitted altogether with their direct parent edge. Since a pseudo probe corresponds to a real code address, for size savings, the address is encoded as a delta from the previous probe except for the first probe. Variant-sized integer encoding, aka LEB128, is used for address delta and probe index.
**Assembling**
Pseudo probes can be printed as assembly directives alternatively. This allows for good assembly code readability and also provides a view of how optimizations and pseudo probes affect each other, especially helpful for diff time assembly analysis.
A pseudo probe directive has the following operands in order: function GUID, probe index, probe type, probe attributes and inline context. The directive is generated by the compiler and can be parsed by the assembler to form an encoded `.pseudoprobe` section in the object file.
A example assembly looks like:
```
foo2: # @foo2
# %bb.0: # %bb0
pushq %rax
testl %edi, %edi
.pseudoprobe 837061429793323041 1 0 0
je .LBB1_1
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 6 2 0
callq foo
.pseudoprobe 837061429793323041 3 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
.LBB1_1: # %bb1
.pseudoprobe 837061429793323041 5 1 0
callq *%rsi
.pseudoprobe 837061429793323041 2 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
# -- End function
.section .pseudo_probe_desc,"",@progbits
.quad 6699318081062747564
.quad 72617220756
.byte 3
.ascii "foo"
.quad 837061429793323041
.quad 281547593931412
.byte 4
.ascii "foo2"
```
With inlining turned on, the assembly may look different around %bb2 with an inlined probe:
```
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 3 0
.pseudoprobe 6699318081062747564 1 0 @ 837061429793323041:6
.pseudoprobe 837061429793323041 4 0
popq %rax
retq
```
**Disassembling**
We have a disassembling tool (llvm-profgen) that can display disassembly alongside with pseudo probes. So far it only supports ELF executable file.
An example disassembly looks like:
```
00000000002011a0 <foo2>:
2011a0: 50 push rax
2011a1: 85 ff test edi,edi
[Probe]: FUNC: foo2 Index: 1 Type: Block
2011a3: 74 02 je 2011a7 <foo2+0x7>
[Probe]: FUNC: foo2 Index: 3 Type: Block
[Probe]: FUNC: foo2 Index: 4 Type: Block
[Probe]: FUNC: foo Index: 1 Type: Block Inlined: @ foo2:6
2011a5: 58 pop rax
2011a6: c3 ret
[Probe]: FUNC: foo2 Index: 2 Type: Block
2011a7: bf 01 00 00 00 mov edi,0x1
[Probe]: FUNC: foo2 Index: 5 Type: IndirectCall
2011ac: ff d6 call rsi
[Probe]: FUNC: foo2 Index: 4 Type: Block
2011ae: 58 pop rax
2011af: c3 ret
```
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D91878
2020-12-09 07:37:32 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
return PseudoProbeSection;
|
|
|
|
}
|
|
|
|
|
|
|
|
MCSection *
|
|
|
|
MCObjectFileInfo::getPseudoProbeDescSection(StringRef FuncName) const {
|
2021-05-06 01:03:02 +08:00
|
|
|
if (Ctx->getObjectFileType() == MCContext::IsELF) {
|
[CSSPGO] Pseudo probe encoding and emission.
This change implements pseudo probe encoding and emission for CSSPGO. Please see RFC here for more context: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s
Pseudo probes are in the form of intrinsic calls on IR/MIR but they do not turn into any machine instructions. Instead they are emitted into the binary as a piece of data in standalone sections. The probe-specific sections are not needed to be loaded into memory at execution time, thus they do not incur a runtime overhead.
**ELF object emission**
The binary data to emit are organized as two ELF sections, i.e, the `.pseudo_probe_desc` section and the `.pseudo_probe` section. The `.pseudo_probe_desc` section stores a function descriptor for each function and the `.pseudo_probe` section stores the actual probes, each fo which corresponds to an IR basic block or an IR function callsite. A function descriptor is stored as a module-level metadata during the compilation and is serialized into the object file during object emission.
Both the probe descriptors and pseudo probes can be emitted into a separate ELF section per function to leverage the linker for deduplication. A `.pseudo_probe` section shares the same COMDAT group with the function code so that when the function is dead, the probes are dead and disposed too. On the contrary, a `.pseudo_probe_desc` section has its own COMDAT group. This is because even if a function is dead, its probes may be inlined into other functions and its descriptor is still needed by the profile generation tool.
The format of `.pseudo_probe_desc` section looks like:
```
.section .pseudo_probe_desc,"",@progbits
.quad 6309742469962978389 // Func GUID
.quad 4294967295 // Func Hash
.byte 9 // Length of func name
.ascii "_Z5funcAi" // Func name
.quad 7102633082150537521
.quad 138828622701
.byte 12
.ascii "_Z8funcLeafi"
.quad 446061515086924981
.quad 4294967295
.byte 9
.ascii "_Z5funcBi"
.quad -2016976694713209516
.quad 72617220756
.byte 7
.ascii "_Z3fibi"
```
For each `.pseudoprobe` section, the encoded binary data consists of a single function record corresponding to an outlined function (i.e, a function with a code entry in the `.text` section). A function record has the following format :
```
FUNCTION BODY (one for each outlined function present in the text section)
GUID (uint64)
GUID of the function
NPROBES (ULEB128)
Number of probes originating from this function.
NUM_INLINED_FUNCTIONS (ULEB128)
Number of callees inlined into this function, aka number of
first-level inlinees
PROBE RECORDS
A list of NPROBES entries. Each entry contains:
INDEX (ULEB128)
TYPE (uint4)
0 - block probe, 1 - indirect call, 2 - direct call
ATTRIBUTE (uint3)
reserved
ADDRESS_TYPE (uint1)
0 - code address, 1 - address delta
CODE_ADDRESS (uint64 or ULEB128)
code address or address delta, depending on ADDRESS_TYPE
INLINED FUNCTION RECORDS
A list of NUM_INLINED_FUNCTIONS entries describing each of the inlined
callees. Each record contains:
INLINE SITE
GUID of the inlinee (uint64)
ID of the callsite probe (ULEB128)
FUNCTION BODY
A FUNCTION BODY entry describing the inlined function.
```
To support building a context-sensitive profile, probes from inlinees are grouped by their inline contexts. An inline context is logically a call path through which a callee function lands in a caller function. The probe emitter builds an inline tree based on the debug metadata for each outlined function in the form of a trie tree. A tree root is the outlined function. Each tree edge stands for a callsite where inlining happens. Pseudo probes originating from an inlinee function are stored in a tree node and the tree path starting from the root all the way down to the tree node is the inline context of the probes. The emission happens on the whole tree top-down recursively. Probes of a tree node will be emitted altogether with their direct parent edge. Since a pseudo probe corresponds to a real code address, for size savings, the address is encoded as a delta from the previous probe except for the first probe. Variant-sized integer encoding, aka LEB128, is used for address delta and probe index.
**Assembling**
Pseudo probes can be printed as assembly directives alternatively. This allows for good assembly code readability and also provides a view of how optimizations and pseudo probes affect each other, especially helpful for diff time assembly analysis.
A pseudo probe directive has the following operands in order: function GUID, probe index, probe type, probe attributes and inline context. The directive is generated by the compiler and can be parsed by the assembler to form an encoded `.pseudoprobe` section in the object file.
A example assembly looks like:
```
foo2: # @foo2
# %bb.0: # %bb0
pushq %rax
testl %edi, %edi
.pseudoprobe 837061429793323041 1 0 0
je .LBB1_1
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 6 2 0
callq foo
.pseudoprobe 837061429793323041 3 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
.LBB1_1: # %bb1
.pseudoprobe 837061429793323041 5 1 0
callq *%rsi
.pseudoprobe 837061429793323041 2 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
# -- End function
.section .pseudo_probe_desc,"",@progbits
.quad 6699318081062747564
.quad 72617220756
.byte 3
.ascii "foo"
.quad 837061429793323041
.quad 281547593931412
.byte 4
.ascii "foo2"
```
With inlining turned on, the assembly may look different around %bb2 with an inlined probe:
```
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 3 0
.pseudoprobe 6699318081062747564 1 0 @ 837061429793323041:6
.pseudoprobe 837061429793323041 4 0
popq %rax
retq
```
**Disassembling**
We have a disassembling tool (llvm-profgen) that can display disassembly alongside with pseudo probes. So far it only supports ELF executable file.
An example disassembly looks like:
```
00000000002011a0 <foo2>:
2011a0: 50 push rax
2011a1: 85 ff test edi,edi
[Probe]: FUNC: foo2 Index: 1 Type: Block
2011a3: 74 02 je 2011a7 <foo2+0x7>
[Probe]: FUNC: foo2 Index: 3 Type: Block
[Probe]: FUNC: foo2 Index: 4 Type: Block
[Probe]: FUNC: foo Index: 1 Type: Block Inlined: @ foo2:6
2011a5: 58 pop rax
2011a6: c3 ret
[Probe]: FUNC: foo2 Index: 2 Type: Block
2011a7: bf 01 00 00 00 mov edi,0x1
[Probe]: FUNC: foo2 Index: 5 Type: IndirectCall
2011ac: ff d6 call rsi
[Probe]: FUNC: foo2 Index: 4 Type: Block
2011ae: 58 pop rax
2011af: c3 ret
```
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D91878
2020-12-09 07:37:32 +08:00
|
|
|
// Create a separate comdat group for each function's descriptor in order
|
|
|
|
// for the linker to deduplicate. The duplication, must be from different
|
|
|
|
// tranlation unit, can come from:
|
|
|
|
// 1. Inline functions defined in header files;
|
|
|
|
// 2. ThinLTO imported funcions;
|
|
|
|
// 3. Weak-linkage definitions.
|
|
|
|
// Use a concatenation of the section name and the function name as the
|
|
|
|
// group name so that descriptor-only groups won't be folded with groups of
|
|
|
|
// code.
|
2021-05-06 01:03:02 +08:00
|
|
|
if (Ctx->getTargetTriple().supportsCOMDAT() && !FuncName.empty()) {
|
[CSSPGO] Pseudo probe encoding and emission.
This change implements pseudo probe encoding and emission for CSSPGO. Please see RFC here for more context: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s
Pseudo probes are in the form of intrinsic calls on IR/MIR but they do not turn into any machine instructions. Instead they are emitted into the binary as a piece of data in standalone sections. The probe-specific sections are not needed to be loaded into memory at execution time, thus they do not incur a runtime overhead.
**ELF object emission**
The binary data to emit are organized as two ELF sections, i.e, the `.pseudo_probe_desc` section and the `.pseudo_probe` section. The `.pseudo_probe_desc` section stores a function descriptor for each function and the `.pseudo_probe` section stores the actual probes, each fo which corresponds to an IR basic block or an IR function callsite. A function descriptor is stored as a module-level metadata during the compilation and is serialized into the object file during object emission.
Both the probe descriptors and pseudo probes can be emitted into a separate ELF section per function to leverage the linker for deduplication. A `.pseudo_probe` section shares the same COMDAT group with the function code so that when the function is dead, the probes are dead and disposed too. On the contrary, a `.pseudo_probe_desc` section has its own COMDAT group. This is because even if a function is dead, its probes may be inlined into other functions and its descriptor is still needed by the profile generation tool.
The format of `.pseudo_probe_desc` section looks like:
```
.section .pseudo_probe_desc,"",@progbits
.quad 6309742469962978389 // Func GUID
.quad 4294967295 // Func Hash
.byte 9 // Length of func name
.ascii "_Z5funcAi" // Func name
.quad 7102633082150537521
.quad 138828622701
.byte 12
.ascii "_Z8funcLeafi"
.quad 446061515086924981
.quad 4294967295
.byte 9
.ascii "_Z5funcBi"
.quad -2016976694713209516
.quad 72617220756
.byte 7
.ascii "_Z3fibi"
```
For each `.pseudoprobe` section, the encoded binary data consists of a single function record corresponding to an outlined function (i.e, a function with a code entry in the `.text` section). A function record has the following format :
```
FUNCTION BODY (one for each outlined function present in the text section)
GUID (uint64)
GUID of the function
NPROBES (ULEB128)
Number of probes originating from this function.
NUM_INLINED_FUNCTIONS (ULEB128)
Number of callees inlined into this function, aka number of
first-level inlinees
PROBE RECORDS
A list of NPROBES entries. Each entry contains:
INDEX (ULEB128)
TYPE (uint4)
0 - block probe, 1 - indirect call, 2 - direct call
ATTRIBUTE (uint3)
reserved
ADDRESS_TYPE (uint1)
0 - code address, 1 - address delta
CODE_ADDRESS (uint64 or ULEB128)
code address or address delta, depending on ADDRESS_TYPE
INLINED FUNCTION RECORDS
A list of NUM_INLINED_FUNCTIONS entries describing each of the inlined
callees. Each record contains:
INLINE SITE
GUID of the inlinee (uint64)
ID of the callsite probe (ULEB128)
FUNCTION BODY
A FUNCTION BODY entry describing the inlined function.
```
To support building a context-sensitive profile, probes from inlinees are grouped by their inline contexts. An inline context is logically a call path through which a callee function lands in a caller function. The probe emitter builds an inline tree based on the debug metadata for each outlined function in the form of a trie tree. A tree root is the outlined function. Each tree edge stands for a callsite where inlining happens. Pseudo probes originating from an inlinee function are stored in a tree node and the tree path starting from the root all the way down to the tree node is the inline context of the probes. The emission happens on the whole tree top-down recursively. Probes of a tree node will be emitted altogether with their direct parent edge. Since a pseudo probe corresponds to a real code address, for size savings, the address is encoded as a delta from the previous probe except for the first probe. Variant-sized integer encoding, aka LEB128, is used for address delta and probe index.
**Assembling**
Pseudo probes can be printed as assembly directives alternatively. This allows for good assembly code readability and also provides a view of how optimizations and pseudo probes affect each other, especially helpful for diff time assembly analysis.
A pseudo probe directive has the following operands in order: function GUID, probe index, probe type, probe attributes and inline context. The directive is generated by the compiler and can be parsed by the assembler to form an encoded `.pseudoprobe` section in the object file.
A example assembly looks like:
```
foo2: # @foo2
# %bb.0: # %bb0
pushq %rax
testl %edi, %edi
.pseudoprobe 837061429793323041 1 0 0
je .LBB1_1
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 6 2 0
callq foo
.pseudoprobe 837061429793323041 3 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
.LBB1_1: # %bb1
.pseudoprobe 837061429793323041 5 1 0
callq *%rsi
.pseudoprobe 837061429793323041 2 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
# -- End function
.section .pseudo_probe_desc,"",@progbits
.quad 6699318081062747564
.quad 72617220756
.byte 3
.ascii "foo"
.quad 837061429793323041
.quad 281547593931412
.byte 4
.ascii "foo2"
```
With inlining turned on, the assembly may look different around %bb2 with an inlined probe:
```
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 3 0
.pseudoprobe 6699318081062747564 1 0 @ 837061429793323041:6
.pseudoprobe 837061429793323041 4 0
popq %rax
retq
```
**Disassembling**
We have a disassembling tool (llvm-profgen) that can display disassembly alongside with pseudo probes. So far it only supports ELF executable file.
An example disassembly looks like:
```
00000000002011a0 <foo2>:
2011a0: 50 push rax
2011a1: 85 ff test edi,edi
[Probe]: FUNC: foo2 Index: 1 Type: Block
2011a3: 74 02 je 2011a7 <foo2+0x7>
[Probe]: FUNC: foo2 Index: 3 Type: Block
[Probe]: FUNC: foo2 Index: 4 Type: Block
[Probe]: FUNC: foo Index: 1 Type: Block Inlined: @ foo2:6
2011a5: 58 pop rax
2011a6: c3 ret
[Probe]: FUNC: foo2 Index: 2 Type: Block
2011a7: bf 01 00 00 00 mov edi,0x1
[Probe]: FUNC: foo2 Index: 5 Type: IndirectCall
2011ac: ff d6 call rsi
[Probe]: FUNC: foo2 Index: 4 Type: Block
2011ae: 58 pop rax
2011af: c3 ret
```
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D91878
2020-12-09 07:37:32 +08:00
|
|
|
auto *S = static_cast<MCSectionELF *>(PseudoProbeDescSection);
|
|
|
|
auto Flags = S->getFlags() | ELF::SHF_GROUP;
|
|
|
|
return Ctx->getELFSection(S->getName(), S->getType(), Flags,
|
|
|
|
S->getEntrySize(),
|
2021-02-01 14:42:35 +08:00
|
|
|
S->getName() + "_" + FuncName,
|
|
|
|
/*IsComdat=*/true);
|
[CSSPGO] Pseudo probe encoding and emission.
This change implements pseudo probe encoding and emission for CSSPGO. Please see RFC here for more context: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s
Pseudo probes are in the form of intrinsic calls on IR/MIR but they do not turn into any machine instructions. Instead they are emitted into the binary as a piece of data in standalone sections. The probe-specific sections are not needed to be loaded into memory at execution time, thus they do not incur a runtime overhead.
**ELF object emission**
The binary data to emit are organized as two ELF sections, i.e, the `.pseudo_probe_desc` section and the `.pseudo_probe` section. The `.pseudo_probe_desc` section stores a function descriptor for each function and the `.pseudo_probe` section stores the actual probes, each fo which corresponds to an IR basic block or an IR function callsite. A function descriptor is stored as a module-level metadata during the compilation and is serialized into the object file during object emission.
Both the probe descriptors and pseudo probes can be emitted into a separate ELF section per function to leverage the linker for deduplication. A `.pseudo_probe` section shares the same COMDAT group with the function code so that when the function is dead, the probes are dead and disposed too. On the contrary, a `.pseudo_probe_desc` section has its own COMDAT group. This is because even if a function is dead, its probes may be inlined into other functions and its descriptor is still needed by the profile generation tool.
The format of `.pseudo_probe_desc` section looks like:
```
.section .pseudo_probe_desc,"",@progbits
.quad 6309742469962978389 // Func GUID
.quad 4294967295 // Func Hash
.byte 9 // Length of func name
.ascii "_Z5funcAi" // Func name
.quad 7102633082150537521
.quad 138828622701
.byte 12
.ascii "_Z8funcLeafi"
.quad 446061515086924981
.quad 4294967295
.byte 9
.ascii "_Z5funcBi"
.quad -2016976694713209516
.quad 72617220756
.byte 7
.ascii "_Z3fibi"
```
For each `.pseudoprobe` section, the encoded binary data consists of a single function record corresponding to an outlined function (i.e, a function with a code entry in the `.text` section). A function record has the following format :
```
FUNCTION BODY (one for each outlined function present in the text section)
GUID (uint64)
GUID of the function
NPROBES (ULEB128)
Number of probes originating from this function.
NUM_INLINED_FUNCTIONS (ULEB128)
Number of callees inlined into this function, aka number of
first-level inlinees
PROBE RECORDS
A list of NPROBES entries. Each entry contains:
INDEX (ULEB128)
TYPE (uint4)
0 - block probe, 1 - indirect call, 2 - direct call
ATTRIBUTE (uint3)
reserved
ADDRESS_TYPE (uint1)
0 - code address, 1 - address delta
CODE_ADDRESS (uint64 or ULEB128)
code address or address delta, depending on ADDRESS_TYPE
INLINED FUNCTION RECORDS
A list of NUM_INLINED_FUNCTIONS entries describing each of the inlined
callees. Each record contains:
INLINE SITE
GUID of the inlinee (uint64)
ID of the callsite probe (ULEB128)
FUNCTION BODY
A FUNCTION BODY entry describing the inlined function.
```
To support building a context-sensitive profile, probes from inlinees are grouped by their inline contexts. An inline context is logically a call path through which a callee function lands in a caller function. The probe emitter builds an inline tree based on the debug metadata for each outlined function in the form of a trie tree. A tree root is the outlined function. Each tree edge stands for a callsite where inlining happens. Pseudo probes originating from an inlinee function are stored in a tree node and the tree path starting from the root all the way down to the tree node is the inline context of the probes. The emission happens on the whole tree top-down recursively. Probes of a tree node will be emitted altogether with their direct parent edge. Since a pseudo probe corresponds to a real code address, for size savings, the address is encoded as a delta from the previous probe except for the first probe. Variant-sized integer encoding, aka LEB128, is used for address delta and probe index.
**Assembling**
Pseudo probes can be printed as assembly directives alternatively. This allows for good assembly code readability and also provides a view of how optimizations and pseudo probes affect each other, especially helpful for diff time assembly analysis.
A pseudo probe directive has the following operands in order: function GUID, probe index, probe type, probe attributes and inline context. The directive is generated by the compiler and can be parsed by the assembler to form an encoded `.pseudoprobe` section in the object file.
A example assembly looks like:
```
foo2: # @foo2
# %bb.0: # %bb0
pushq %rax
testl %edi, %edi
.pseudoprobe 837061429793323041 1 0 0
je .LBB1_1
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 6 2 0
callq foo
.pseudoprobe 837061429793323041 3 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
.LBB1_1: # %bb1
.pseudoprobe 837061429793323041 5 1 0
callq *%rsi
.pseudoprobe 837061429793323041 2 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
# -- End function
.section .pseudo_probe_desc,"",@progbits
.quad 6699318081062747564
.quad 72617220756
.byte 3
.ascii "foo"
.quad 837061429793323041
.quad 281547593931412
.byte 4
.ascii "foo2"
```
With inlining turned on, the assembly may look different around %bb2 with an inlined probe:
```
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 3 0
.pseudoprobe 6699318081062747564 1 0 @ 837061429793323041:6
.pseudoprobe 837061429793323041 4 0
popq %rax
retq
```
**Disassembling**
We have a disassembling tool (llvm-profgen) that can display disassembly alongside with pseudo probes. So far it only supports ELF executable file.
An example disassembly looks like:
```
00000000002011a0 <foo2>:
2011a0: 50 push rax
2011a1: 85 ff test edi,edi
[Probe]: FUNC: foo2 Index: 1 Type: Block
2011a3: 74 02 je 2011a7 <foo2+0x7>
[Probe]: FUNC: foo2 Index: 3 Type: Block
[Probe]: FUNC: foo2 Index: 4 Type: Block
[Probe]: FUNC: foo Index: 1 Type: Block Inlined: @ foo2:6
2011a5: 58 pop rax
2011a6: c3 ret
[Probe]: FUNC: foo2 Index: 2 Type: Block
2011a7: bf 01 00 00 00 mov edi,0x1
[Probe]: FUNC: foo2 Index: 5 Type: IndirectCall
2011ac: ff d6 call rsi
[Probe]: FUNC: foo2 Index: 4 Type: Block
2011ae: 58 pop rax
2011af: c3 ret
```
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D91878
2020-12-09 07:37:32 +08:00
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}
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}
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return PseudoProbeDescSection;
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}
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