[llvm] r261462 - [X86] Use the correct alignment for COMDAT constant pool entries
David Majnemer via llvm-commits
llvm-commits at lists.llvm.org
Sat Feb 20 17:30:31 PST 2016
Author: majnemer
Date: Sat Feb 20 19:30:30 2016
New Revision: 261462
URL: http://llvm.org/viewvc/llvm-project?rev=261462&view=rev
Log:
[X86] Use the correct alignment for COMDAT constant pool entries
COFF doesn't have sections with mergeable contents. Instead, each
constant pool entry ends up in a COMDAT section. The linker, when
choosing between COMDAT sections, doesn't choose the max alignment of
the two sections. You just get whatever alignment was on the section.
If one constant needed a higher alignment in one object file from
another one, then we will get into trouble if the linker chooses the
lower alignment one.
Instead, lets promote the alignment of the constant pool entry to make
sure we don't use an under aligned constant with an instruction which
assumed otherwise.
This fixes PR26680.
Modified:
llvm/trunk/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
llvm/trunk/include/llvm/Target/TargetLoweringObjectFile.h
llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp
llvm/trunk/lib/Target/X86/X86AsmPrinter.cpp
llvm/trunk/lib/Target/X86/X86TargetObjectFile.cpp
llvm/trunk/lib/Target/X86/X86TargetObjectFile.h
llvm/trunk/test/CodeGen/X86/win_cst_pool.ll
Modified: llvm/trunk/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h?rev=261462&r1=261461&r2=261462&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h (original)
+++ llvm/trunk/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h Sat Feb 20 19:30:30 2016
@@ -47,7 +47,8 @@ public:
/// Given a constant with the SectionKind, return a section that it should be
/// placed in.
MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
- const Constant *C) const override;
+ const Constant *C,
+ unsigned &Align) const override;
MCSection *getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler &Mang,
@@ -104,7 +105,8 @@ public:
const TargetMachine &TM) const override;
MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
- const Constant *C) const override;
+ const Constant *C,
+ unsigned &Align) const override;
/// The mach-o version of this method defaults to returning a stub reference.
const MCExpr *
Modified: llvm/trunk/include/llvm/Target/TargetLoweringObjectFile.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetLoweringObjectFile.h?rev=261462&r1=261461&r2=261462&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetLoweringObjectFile.h (original)
+++ llvm/trunk/include/llvm/Target/TargetLoweringObjectFile.h Sat Feb 20 19:30:30 2016
@@ -71,7 +71,8 @@ public:
/// placed in.
virtual MCSection *getSectionForConstant(const DataLayout &DL,
SectionKind Kind,
- const Constant *C) const;
+ const Constant *C,
+ unsigned &Align) const;
/// Classify the specified global variable into a set of target independent
/// categories embodied in SectionKind.
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp?rev=261462&r1=261461&r2=261462&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp Sat Feb 20 19:30:30 2016
@@ -1194,9 +1194,10 @@ bool AsmPrinter::doFinalization(Module &
// Emit __morestack address if needed for indirect calls.
if (MMI->usesMorestackAddr()) {
+ unsigned Align = 1;
MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant(
getDataLayout(), SectionKind::getReadOnly(),
- /*C=*/nullptr);
+ /*C=*/nullptr, Align);
OutStreamer->SwitchSection(ReadOnlySection);
MCSymbol *AddrSymbol =
@@ -1286,8 +1287,8 @@ void AsmPrinter::EmitConstantPool() {
if (!CPE.isMachineConstantPoolEntry())
C = CPE.Val.ConstVal;
- MCSection *S =
- getObjFileLowering().getSectionForConstant(getDataLayout(), Kind, C);
+ MCSection *S = getObjFileLowering().getSectionForConstant(getDataLayout(),
+ Kind, C, Align);
// The number of sections are small, just do a linear search from the
// last section to the first.
Modified: llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp?rev=261462&r1=261461&r2=261462&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp (original)
+++ llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp Sat Feb 20 19:30:30 2016
@@ -351,7 +351,8 @@ bool TargetLoweringObjectFileELF::should
/// Given a mergeable constant with the specified size and relocation
/// information, return a section that it should be placed in.
MCSection *TargetLoweringObjectFileELF::getSectionForConstant(
- const DataLayout &DL, SectionKind Kind, const Constant *C) const {
+ const DataLayout &DL, SectionKind Kind, const Constant *C,
+ unsigned &Align) const {
if (Kind.isMergeableConst4() && MergeableConst4Section)
return MergeableConst4Section;
if (Kind.isMergeableConst8() && MergeableConst8Section)
@@ -636,7 +637,8 @@ MCSection *TargetLoweringObjectFileMachO
}
MCSection *TargetLoweringObjectFileMachO::getSectionForConstant(
- const DataLayout &DL, SectionKind Kind, const Constant *C) const {
+ const DataLayout &DL, SectionKind Kind, const Constant *C,
+ unsigned &Align) const {
// If this constant requires a relocation, we have to put it in the data
// segment, not in the text segment.
if (Kind.isData() || Kind.isReadOnlyWithRel())
Modified: llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp?rev=261462&r1=261461&r2=261462&view=diff
==============================================================================
--- llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp (original)
+++ llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp Sat Feb 20 19:30:30 2016
@@ -252,8 +252,10 @@ TargetLoweringObjectFile::SectionForGlob
MCSection *TargetLoweringObjectFile::getSectionForJumpTable(
const Function &F, Mangler &Mang, const TargetMachine &TM) const {
+ unsigned Align = 0;
return getSectionForConstant(F.getParent()->getDataLayout(),
- SectionKind::getReadOnly(), /*C=*/nullptr);
+ SectionKind::getReadOnly(), /*C=*/nullptr,
+ Align);
}
bool TargetLoweringObjectFile::shouldPutJumpTableInFunctionSection(
@@ -277,7 +279,8 @@ bool TargetLoweringObjectFile::shouldPut
/// Given a mergable constant with the specified size and relocation
/// information, return a section that it should be placed in.
MCSection *TargetLoweringObjectFile::getSectionForConstant(
- const DataLayout &DL, SectionKind Kind, const Constant *C) const {
+ const DataLayout &DL, SectionKind Kind, const Constant *C,
+ unsigned &Align) const {
if (Kind.isReadOnly() && ReadOnlySection != nullptr)
return ReadOnlySection;
Modified: llvm/trunk/lib/Target/X86/X86AsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86AsmPrinter.cpp?rev=261462&r1=261461&r2=261462&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86AsmPrinter.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86AsmPrinter.cpp Sat Feb 20 19:30:30 2016
@@ -568,8 +568,9 @@ MCSymbol *X86AsmPrinter::GetCPISymbol(un
const DataLayout &DL = MF->getDataLayout();
SectionKind Kind = CPE.getSectionKind(&DL);
const Constant *C = CPE.Val.ConstVal;
+ unsigned Align = CPE.Alignment;
if (const MCSectionCOFF *S = dyn_cast<MCSectionCOFF>(
- getObjFileLowering().getSectionForConstant(DL, Kind, C))) {
+ getObjFileLowering().getSectionForConstant(DL, Kind, C, Align))) {
if (MCSymbol *Sym = S->getCOMDATSymbol()) {
if (Sym->isUndefined())
OutStreamer->EmitSymbolAttribute(Sym, MCSA_Global);
Modified: llvm/trunk/lib/Target/X86/X86TargetObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86TargetObjectFile.cpp?rev=261462&r1=261461&r2=261462&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86TargetObjectFile.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86TargetObjectFile.cpp Sat Feb 20 19:30:30 2016
@@ -154,16 +154,29 @@ static std::string scalarConstantToHexSt
}
MCSection *X86WindowsTargetObjectFile::getSectionForConstant(
- const DataLayout &DL, SectionKind Kind, const Constant *C) const {
+ const DataLayout &DL, SectionKind Kind, const Constant *C,
+ unsigned &Align) const {
if (Kind.isMergeableConst() && C) {
const unsigned Characteristics = COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_LNK_COMDAT;
std::string COMDATSymName;
- if (Kind.isMergeableConst4() || Kind.isMergeableConst8())
- COMDATSymName = "__real@" + scalarConstantToHexString(C);
- else if (Kind.isMergeableConst16())
- COMDATSymName = "__xmm@" + scalarConstantToHexString(C);
+ if (Kind.isMergeableConst4()) {
+ if (Align <= 4) {
+ COMDATSymName = "__real@" + scalarConstantToHexString(C);
+ Align = 4;
+ }
+ } else if (Kind.isMergeableConst8()) {
+ if (Align <= 8) {
+ COMDATSymName = "__real@" + scalarConstantToHexString(C);
+ Align = 8;
+ }
+ } else if (Kind.isMergeableConst16()) {
+ if (Align <= 16) {
+ COMDATSymName = "__xmm@" + scalarConstantToHexString(C);
+ Align = 16;
+ }
+ }
if (!COMDATSymName.empty())
return getContext().getCOFFSection(".rdata", Characteristics, Kind,
@@ -171,5 +184,5 @@ MCSection *X86WindowsTargetObjectFile::g
COFF::IMAGE_COMDAT_SELECT_ANY);
}
- return TargetLoweringObjectFile::getSectionForConstant(DL, Kind, C);
+ return TargetLoweringObjectFile::getSectionForConstant(DL, Kind, C, Align);
}
Modified: llvm/trunk/lib/Target/X86/X86TargetObjectFile.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86TargetObjectFile.h?rev=261462&r1=261461&r2=261462&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86TargetObjectFile.h (original)
+++ llvm/trunk/lib/Target/X86/X86TargetObjectFile.h Sat Feb 20 19:30:30 2016
@@ -59,7 +59,8 @@ namespace llvm {
/// \brief Given a mergeable constant with the specified size and relocation
/// information, return a section that it should be placed in.
MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
- const Constant *C) const override;
+ const Constant *C,
+ unsigned &Align) const override;
};
} // end namespace llvm
Modified: llvm/trunk/test/CodeGen/X86/win_cst_pool.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/win_cst_pool.ll?rev=261462&r1=261461&r2=261462&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/win_cst_pool.ll (original)
+++ llvm/trunk/test/CodeGen/X86/win_cst_pool.ll Sat Feb 20 19:30:30 2016
@@ -73,7 +73,7 @@ define float @pr23966(i32 %a) {
; CHECK: .globl __real at bf8000003f800000
; CHECK-NEXT: .section .rdata,"dr",discard,__real at bf8000003f800000
-; CHECK-NEXT: .p2align 2
+; CHECK-NEXT: .p2align 3
; CHECK-NEXT: __real at bf8000003f800000:
; CHECK-NEXT: .long 1065353216
; CHECK-NEXT: .long 3212836864
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