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author | Rafael Espindola <rafael.espindola@gmail.com> | 2013-10-30 22:08:11 +0000 |
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committer | Rafael Espindola <rafael.espindola@gmail.com> | 2013-10-30 22:08:11 +0000 |
commit | 2cc546db188d5e4d4537681cab3d52781125518c (patch) | |
tree | 82d4b69f91bc14eebc0663452c579b100a270633 /lib/CodeGen/AsmPrinter/AsmPrinter.cpp | |
parent | 1d36113c05e611c0fba9b872b5f03eca9848bd69 (diff) | |
download | external_llvm-2cc546db188d5e4d4537681cab3d52781125518c.zip external_llvm-2cc546db188d5e4d4537681cab3d52781125518c.tar.gz external_llvm-2cc546db188d5e4d4537681cab3d52781125518c.tar.bz2 |
Produce .weak_def_can_be_hidden for some linkonce_odr values
With this patch llvm produces a weak_def_can_be_hidden for linkonce_odr
if they are also unnamed_addr or don't have their address taken.
There is not a lot of documentation about .weak_def_can_be_hidden, but
from the old discussion about linkonce_odr_auto_hide and the name of
the directive this looks correct: these symbols can be hidden.
Testing this with the ld64 in Xcode 5 linking clang reduces the number of
exported symbols from 21053 to 19049.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193718 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/AsmPrinter/AsmPrinter.cpp')
-rw-r--r-- | lib/CodeGen/AsmPrinter/AsmPrinter.cpp | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp index 41d83be..9a02462 100644 --- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp +++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp @@ -48,6 +48,7 @@ #include "llvm/Target/TargetLoweringObjectFile.h" #include "llvm/Target/TargetOptions.h" #include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Transforms/Utils/GlobalStatus.h" using namespace llvm; static const char *const DWARFGroupName = "DWARF Emission"; @@ -212,9 +213,8 @@ bool AsmPrinter::doInitialization(Module &M) { llvm_unreachable("Unknown exception type."); } -void AsmPrinter::EmitLinkage(unsigned L, MCSymbol *GVSym) const { - GlobalValue::LinkageTypes Linkage = (GlobalValue::LinkageTypes)L; - +void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const { + GlobalValue::LinkageTypes Linkage = GV->getLinkage(); switch (Linkage) { case GlobalValue::CommonLinkage: case GlobalValue::LinkOnceAnyLinkage: @@ -227,7 +227,20 @@ void AsmPrinter::EmitLinkage(unsigned L, MCSymbol *GVSym) const { // .globl _foo OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global); - if (Linkage != GlobalValue::LinkOnceODRAutoHideLinkage) + + bool CanBeHidden = Linkage == GlobalValue::LinkOnceODRAutoHideLinkage; + + if (!CanBeHidden && Linkage == GlobalValue::LinkOnceODRLinkage) { + if (GV->hasUnnamedAddr()) { + CanBeHidden = true; + } else { + GlobalStatus GS; + if (!GlobalStatus::analyzeGlobal(GV, GS) && !GS.IsCompared) + CanBeHidden = true; + } + } + + if (!CanBeHidden) // .weak_definition _foo OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition); else @@ -399,7 +412,7 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) { OutStreamer.SwitchSection(TLVSect); // Emit the linkage here. - EmitLinkage(GV->getLinkage(), GVSym); + EmitLinkage(GV, GVSym); OutStreamer.EmitLabel(GVSym); // Three pointers in size: @@ -418,7 +431,7 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) { OutStreamer.SwitchSection(TheSection); - EmitLinkage(GV->getLinkage(), GVSym); + EmitLinkage(GV, GVSym); EmitAlignment(AlignLog, GV); OutStreamer.EmitLabel(GVSym); @@ -444,7 +457,7 @@ void AsmPrinter::EmitFunctionHeader() { OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM)); EmitVisibility(CurrentFnSym, F->getVisibility()); - EmitLinkage(F->getLinkage(), CurrentFnSym); + EmitLinkage(F, CurrentFnSym); EmitAlignment(MF->getAlignment(), F); if (MAI->hasDotTypeDotSizeDirective()) |