llvm-project/llvm/lib/CodeGen/AsmPrinter/AddressPool.cpp

67 lines
2.2 KiB
C++

//===- llvm/CodeGen/AddressPool.cpp - Dwarf Debug Framework ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "AddressPool.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include <utility>
using namespace llvm;
unsigned AddressPool::getIndex(const MCSymbol *Sym, bool TLS) {
HasBeenUsed = true;
auto IterBool =
Pool.insert(std::make_pair(Sym, AddressPoolEntry(Pool.size(), TLS)));
return IterBool.first->second.Number;
}
void AddressPool::emitHeader(AsmPrinter &Asm, MCSection *Section) {
static const uint8_t AddrSize = Asm.getDataLayout().getPointerSize();
uint64_t Length = sizeof(uint16_t) // version
+ sizeof(uint8_t) // address_size
+ sizeof(uint8_t) // segment_selector_size
+ AddrSize * Pool.size(); // entries
Asm.emitInt32(Length); // TODO: Support DWARF64 format.
Asm.emitInt16(Asm.getDwarfVersion());
Asm.emitInt8(AddrSize);
Asm.emitInt8(0); // TODO: Support non-zero segment_selector_size.
}
// Emit addresses into the section given.
void AddressPool::emit(AsmPrinter &Asm, MCSection *AddrSection) {
if (isEmpty())
return;
// Start the dwarf addr section.
Asm.OutStreamer->SwitchSection(AddrSection);
if (Asm.getDwarfVersion() >= 5)
emitHeader(Asm, AddrSection);
// Define the symbol that marks the start of the contribution.
// It is referenced via DW_AT_addr_base.
Asm.OutStreamer->EmitLabel(AddressTableBaseSym);
// Order the address pool entries by ID
SmallVector<const MCExpr *, 64> Entries(Pool.size());
for (const auto &I : Pool)
Entries[I.second.Number] =
I.second.TLS
? Asm.getObjFileLowering().getDebugThreadLocalSymbol(I.first)
: MCSymbolRefExpr::create(I.first, Asm.OutContext);
for (const MCExpr *Entry : Entries)
Asm.OutStreamer->EmitValue(Entry, Asm.getDataLayout().getPointerSize());
}