2015-08-14 22:12:54 +08:00
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//===- Config.h -------------------------------------------------*- C++ -*-===//
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2015-07-25 05:03:07 +08:00
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLD_ELF_CONFIG_H
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#define LLD_ELF_CONFIG_H
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2015-11-12 17:52:08 +08:00
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#include "llvm/ADT/MapVector.h"
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2015-07-25 05:03:07 +08:00
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#include "llvm/ADT/StringRef.h"
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2015-10-07 17:13:03 +08:00
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#include "llvm/Support/ELF.h"
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2015-07-25 05:03:07 +08:00
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2015-09-28 21:11:36 +08:00
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#include <vector>
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2015-07-25 05:03:07 +08:00
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namespace lld {
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2016-02-28 08:25:54 +08:00
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namespace elf {
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2015-07-25 05:03:07 +08:00
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2015-10-12 09:55:32 +08:00
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class InputFile;
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2015-10-10 05:12:40 +08:00
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class SymbolBody;
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2015-10-07 17:13:03 +08:00
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enum ELFKind {
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ELFNoneKind,
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ELF32LEKind,
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ELF32BEKind,
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ELF64LEKind,
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ELF64BEKind
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};
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2016-01-06 01:55:05 +08:00
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// This struct contains the global configuration for the linker.
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// Most fields are direct mapping from the command line options
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// and such fields have the same name as the corresponding options.
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// Most fields are initialized by the driver.
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2015-07-25 05:03:07 +08:00
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struct Configuration {
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2015-10-10 05:12:40 +08:00
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SymbolBody *EntrySym = nullptr;
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2015-12-16 22:45:09 +08:00
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SymbolBody *MipsGpDisp = nullptr;
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2016-02-04 20:09:49 +08:00
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SymbolBody *MipsLocalGp = nullptr;
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2015-10-12 09:55:32 +08:00
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InputFile *FirstElf = nullptr;
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2015-09-12 02:49:42 +08:00
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llvm::StringRef DynamicLinker;
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2015-09-30 06:33:21 +08:00
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llvm::StringRef Entry;
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2015-10-11 11:36:49 +08:00
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llvm::StringRef Emulation;
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2015-10-08 03:34:51 +08:00
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llvm::StringRef Fini;
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llvm::StringRef Init;
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2015-10-07 08:25:09 +08:00
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llvm::StringRef OutputFile;
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2015-10-02 03:36:04 +08:00
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llvm::StringRef SoName;
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2015-09-30 06:33:21 +08:00
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llvm::StringRef Sysroot;
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2015-09-12 05:18:56 +08:00
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std::string RPath;
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2015-10-11 11:28:42 +08:00
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std::vector<llvm::StringRef> SearchPaths;
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2015-10-20 01:35:12 +08:00
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std::vector<llvm::StringRef> Undefined;
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2015-10-01 01:26:13 +08:00
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bool AllowMultipleDefinition;
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2015-10-12 04:59:12 +08:00
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bool AsNeeded = false;
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2015-10-14 05:02:34 +08:00
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bool Bsymbolic;
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2016-02-02 17:28:53 +08:00
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bool BsymbolicFunctions;
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ELF: Implement --build-id.
This patch implements --build-id. After the linker creates an output file
in the memory buffer, it computes the FNV1 hash of the resulting file
and set the hash to the .note section as a build-id.
GNU ld and gold have the same feature, but their default choice of the
hash function is different. Their default is SHA1.
We made a deliberate choice to not use a secure hash function for the
sake of performance. Computing a secure hash is slow -- for example,
MD5 throughput is usually 400 MB/s or so. SHA1 is slower than that.
As a result, if you pass --build-id to gold, then the linker becomes about
10% slower than that without the option. We observed a similar degradation
in an experimental implementation of build-id for LLD. On the other hand,
we observed only 1-2% performance degradation with the FNV hash.
Since build-id is not for digital certificate or anything, we think that
a very small probability of collision is acceptable.
We considered using other signals such as using input file timestamps as
inputs to a secure hash function. But such signals would have an issue
with build reproducibility (if you build a binary from the same source
tree using the same toolchain, the build id should become the same.)
GNU linkers accepts --build-id=<style> option where style is one of
"MD5", "SHA1", or an arbitrary hex string. That option is out of scope
of this patch.
http://reviews.llvm.org/D18091
llvm-svn: 263292
2016-03-12 04:51:53 +08:00
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bool BuildId;
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2016-01-14 02:55:39 +08:00
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bool Demangle = true;
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2015-10-01 01:26:13 +08:00
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bool DiscardAll;
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bool DiscardLocals;
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bool DiscardNone;
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2016-01-15 21:34:52 +08:00
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bool EhFrameHdr;
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2015-10-07 04:02:15 +08:00
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bool EnableNewDtags;
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2015-10-01 01:26:13 +08:00
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bool ExportDynamic;
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ELF2: Implement --gc-sections.
Section garbage collection is a feature to remove unused sections
from outputs. Unused sections are sections that cannot be reachable
from known GC-root symbols or sections. Naturally the feature is
implemented as a mark-sweep garbage collector.
In this patch, I added Live bit to InputSectionBase. If and only
if Live bit is on, the section will be written to the output.
Starting from GC-root symbols or sections, a new function, markLive(),
visits all reachable sections and sets their Live bits. Writer then
ignores sections whose Live bit is off, so that such sections are
excluded from the output.
This change has small negative impact on performance if you use
the feature because making sections means more work. The time to
link Clang changes from 0.356s to 0.386s, or +8%.
It reduces Clang size from 57,764,984 bytes to 55,296,600 bytes.
That is 4.3% reduction.
http://reviews.llvm.org/D13950
llvm-svn: 251043
2015-10-23 02:49:53 +08:00
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bool GcSections;
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2015-10-22 16:21:35 +08:00
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bool GnuHash = false;
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2016-02-26 02:43:51 +08:00
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bool ICF;
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2015-10-17 06:51:43 +08:00
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bool Mips64EL = false;
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2015-10-02 04:14:45 +08:00
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bool NoUndefined;
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2016-03-08 12:06:29 +08:00
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bool NoinhibitExec;
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2016-03-17 13:57:33 +08:00
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bool Pic;
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bool Pie;
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2015-12-10 17:12:18 +08:00
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bool PrintGcSections;
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2016-03-14 04:10:20 +08:00
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bool Rela;
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2016-02-25 16:23:37 +08:00
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bool Relocatable;
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2016-03-10 04:01:08 +08:00
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bool SaveTemps;
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2015-10-01 01:26:13 +08:00
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bool Shared;
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2015-10-02 00:42:03 +08:00
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bool Static = false;
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2015-10-24 16:52:46 +08:00
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bool StripAll;
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2015-10-22 16:21:35 +08:00
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bool SysvHash = true;
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2016-03-11 12:23:12 +08:00
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bool Threads;
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2016-03-29 16:45:40 +08:00
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bool Trace;
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2015-10-11 10:03:03 +08:00
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bool Verbose;
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2016-03-14 17:19:30 +08:00
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bool WarnCommon;
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2015-11-25 02:48:16 +08:00
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bool ZExecStack;
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2015-11-21 05:00:42 +08:00
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bool ZNodelete;
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bool ZNow;
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bool ZOrigin;
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2015-11-24 18:15:50 +08:00
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bool ZRelro;
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2015-10-14 00:20:50 +08:00
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ELFKind EKind = ELFNoneKind;
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2015-10-07 17:13:03 +08:00
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uint16_t EMachine = llvm::ELF::EM_NONE;
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2015-10-15 06:20:57 +08:00
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uint64_t EntryAddr = -1;
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2016-04-01 05:15:31 +08:00
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unsigned LtoO;
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unsigned Optimize;
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2015-07-25 05:03:07 +08:00
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};
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2016-01-06 01:55:05 +08:00
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// The only instance of Configuration struct.
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2015-07-25 05:03:07 +08:00
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extern Configuration *Config;
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2016-02-28 08:25:54 +08:00
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} // namespace elf
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2015-07-25 05:03:07 +08:00
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} // namespace lld
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#endif
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