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-rw-r--r--llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h5
-rw-r--r--llvm/include/llvm/MC/MCAsmInfo.h6
-rw-r--r--llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp23
-rw-r--r--llvm/lib/MC/MCAsmInfoCOFF.cpp11
-rw-r--r--llvm/lib/MC/MCStreamer.cpp21
-rw-r--r--llvm/test/CodeGen/X86/mingw-comdats.ll62
6 files changed, 119 insertions, 9 deletions
diff --git a/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h b/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
index 626703e46f6..98df861dea0 100644
--- a/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
+++ b/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
@@ -134,6 +134,11 @@ public:
class TargetLoweringObjectFileCOFF : public TargetLoweringObjectFile {
mutable unsigned NextUniqueID = 0;
+ /// Append "$symbol" to the section name when targetting mingw. The ld.bfd
+ /// COFF linker will not properly handle comdats otherwise.
+ void appendComdatSymbolForMinGW(SmallVectorImpl<char> &SecName,
+ StringRef Symbol, const DataLayout &DL) const;
+
public:
~TargetLoweringObjectFileCOFF() override = default;
diff --git a/llvm/include/llvm/MC/MCAsmInfo.h b/llvm/include/llvm/MC/MCAsmInfo.h
index ac722a007e9..0a0f37966fc 100644
--- a/llvm/include/llvm/MC/MCAsmInfo.h
+++ b/llvm/include/llvm/MC/MCAsmInfo.h
@@ -84,6 +84,11 @@ protected:
/// directive for emitting thread local BSS Symbols. Default is false.
bool HasMachoTBSSDirective = false;
+ /// True if this is a non-GNU COFF target. The COFF port of the GNU linker
+ /// doesn't handle associative comdats in the way that we would like to use
+ /// them.
+ bool HasCOFFAssociativeComdats = false;
+
/// This is the maximum possible length of an instruction, which is needed to
/// compute the size of an inline asm. Defaults to 4.
unsigned MaxInstLength = 4;
@@ -463,6 +468,7 @@ public:
bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
+ bool hasCOFFAssociativeComdats() const { return HasCOFFAssociativeComdats; }
unsigned getMaxInstLength() const { return MaxInstLength; }
unsigned getMinInstAlignment() const { return MinInstAlignment; }
bool getDollarIsPC() const { return DollarIsPC; }
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 03a1f6239f2..8518ee7def3 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -1060,7 +1060,7 @@ MCSection *TargetLoweringObjectFileCOFF::getExplicitSectionGlobal(
Selection);
}
-static const char *getCOFFSectionNameForUniqueGlobal(SectionKind Kind) {
+static StringRef getCOFFSectionNameForUniqueGlobal(SectionKind Kind) {
if (Kind.isText())
return ".text";
if (Kind.isBSS())
@@ -1072,6 +1072,15 @@ static const char *getCOFFSectionNameForUniqueGlobal(SectionKind Kind) {
return ".data";
}
+void TargetLoweringObjectFileCOFF::appendComdatSymbolForMinGW(
+ SmallVectorImpl<char> &SecName, StringRef Symbol,
+ const DataLayout &DL) const {
+ if (getTargetTriple().isWindowsGNUEnvironment()) {
+ SecName.push_back('$');
+ getMangler().getNameWithPrefix(SecName, Symbol, DL);
+ }
+}
+
MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal(
const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
// If we have -ffunction-sections then we should emit the global value to a
@@ -1083,7 +1092,8 @@ MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal(
EmitUniquedSection = TM.getDataSections();
if ((EmitUniquedSection && !Kind.isCommon()) || GO->hasComdat()) {
- const char *Name = getCOFFSectionNameForUniqueGlobal(Kind);
+ SmallString<256> Name = getCOFFSectionNameForUniqueGlobal(Kind);
+
unsigned Characteristics = getCOFFSectionFlags(Kind, TM);
Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
@@ -1103,6 +1113,8 @@ MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal(
if (!ComdatGV->hasPrivateLinkage()) {
MCSymbol *Sym = TM.getSymbol(ComdatGV);
StringRef COMDATSymName = Sym->getName();
+ appendComdatSymbolForMinGW(Name, COMDATSymName,
+ GO->getParent()->getDataLayout());
return getContext().getCOFFSection(Name, Characteristics, Kind,
COMDATSymName, Selection, UniqueID);
} else {
@@ -1160,13 +1172,14 @@ MCSection *TargetLoweringObjectFileCOFF::getSectionForJumpTable(
StringRef COMDATSymName = Sym->getName();
SectionKind Kind = SectionKind::getReadOnly();
- const char *Name = getCOFFSectionNameForUniqueGlobal(Kind);
+ StringRef SecName = getCOFFSectionNameForUniqueGlobal(Kind);
unsigned Characteristics = getCOFFSectionFlags(Kind, TM);
Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
unsigned UniqueID = NextUniqueID++;
- return getContext().getCOFFSection(Name, Characteristics, Kind, COMDATSymName,
- COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE, UniqueID);
+ return getContext().getCOFFSection(
+ SecName, Characteristics, Kind, COMDATSymName,
+ COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE, UniqueID);
}
void TargetLoweringObjectFileCOFF::emitModuleMetadata(MCStreamer &Streamer,
diff --git a/llvm/lib/MC/MCAsmInfoCOFF.cpp b/llvm/lib/MC/MCAsmInfoCOFF.cpp
index 85104484fd4..8bb02c3f649 100644
--- a/llvm/lib/MC/MCAsmInfoCOFF.cpp
+++ b/llvm/lib/MC/MCAsmInfoCOFF.cpp
@@ -41,6 +41,10 @@ MCAsmInfoCOFF::MCAsmInfoCOFF() {
// At least MSVC inline-asm does AShr.
UseLogicalShr = false;
+
+ // If this is a COFF target, assume that it supports associative comdats. It's
+ // part of the spec.
+ HasCOFFAssociativeComdats = true;
}
void MCAsmInfoMicrosoft::anchor() {}
@@ -49,4 +53,9 @@ MCAsmInfoMicrosoft::MCAsmInfoMicrosoft() = default;
void MCAsmInfoGNUCOFF::anchor() {}
-MCAsmInfoGNUCOFF::MCAsmInfoGNUCOFF() = default;
+MCAsmInfoGNUCOFF::MCAsmInfoGNUCOFF() {
+ // If this is a GNU environment (mingw or cygwin), don't use associative
+ // comdats for jump tables, unwind information, and other data associated with
+ // a function.
+ HasCOFFAssociativeComdats = false;
+}
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 491fec3e9ab..953aa0528fb 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -673,16 +673,31 @@ static MCSection *getWinCFISection(MCContext &Context, unsigned *NextWinCFIID,
return MainCFISec;
const auto *TextSecCOFF = cast<MCSectionCOFF>(TextSec);
+ auto *MainCFISecCOFF = cast<MCSectionCOFF>(MainCFISec);
unsigned UniqueID = TextSecCOFF->getOrAssignWinCFISectionID(NextWinCFIID);
// If this section is COMDAT, this unwind section should be COMDAT associative
// with its group.
const MCSymbol *KeySym = nullptr;
- if (TextSecCOFF->getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT)
+ if (TextSecCOFF->getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
KeySym = TextSecCOFF->getCOMDATSymbol();
- return Context.getAssociativeCOFFSection(cast<MCSectionCOFF>(MainCFISec),
- KeySym, UniqueID);
+ // In a GNU environment, we can't use associative comdats. Instead, do what
+ // GCC does, which is to make plain comdat selectany section named like
+ // ".[px]data$_Z3foov".
+ if (!Context.getAsmInfo()->hasCOFFAssociativeComdats()) {
+ std::string SectionName =
+ (MainCFISecCOFF->getSectionName() + "$" +
+ TextSecCOFF->getSectionName().split('$').second)
+ .str();
+ return Context.getCOFFSection(
+ SectionName,
+ MainCFISecCOFF->getCharacteristics() | COFF::IMAGE_SCN_LNK_COMDAT,
+ MainCFISecCOFF->getKind(), "", COFF::IMAGE_COMDAT_SELECT_ANY);
+ }
+ }
+
+ return Context.getAssociativeCOFFSection(MainCFISecCOFF, KeySym, UniqueID);
}
MCSection *MCStreamer::getAssociatedPDataSection(const MCSection *TextSec) {
diff --git a/llvm/test/CodeGen/X86/mingw-comdats.ll b/llvm/test/CodeGen/X86/mingw-comdats.ll
new file mode 100644
index 00000000000..083885ae918
--- /dev/null
+++ b/llvm/test/CodeGen/X86/mingw-comdats.ll
@@ -0,0 +1,62 @@
+; RUN: llc -mtriple=x86_64-windows-itanium < %s | FileCheck %s
+; RUN: llc -mtriple=x86_64-windows-msvc < %s | FileCheck %s
+; RUN: llc -mtriple=x86_64-w64-windows-gnu < %s | FileCheck %s --check-prefix=GNU
+; RUN: llc -mtriple=x86_64-w64-windows-gnu < %s -filetype=obj | llvm-objdump - -headers | FileCheck %s --check-prefix=GNUOBJ
+
+; GCC and MSVC handle comdats completely differently. Make sure we do the right
+; thing for each.
+
+; Generated with this C++ source:
+; int bar(int);
+; __declspec(selectany) int gv = 42;
+; inline int foo(int x) { return bar(x) + gv; }
+; int main() { return foo(1); }
+
+$_Z3fooi = comdat any
+
+$gv = comdat any
+
+@gv = weak_odr dso_local global i32 42, comdat, align 4
+
+; Function Attrs: norecurse uwtable
+define dso_local i32 @main() #0 {
+entry:
+ %call = tail call i32 @_Z3fooi(i32 1)
+ ret i32 %call
+}
+
+; CHECK: main:
+; GNU: main:
+
+; Function Attrs: inlinehint uwtable
+define linkonce_odr dso_local i32 @_Z3fooi(i32 %x) #1 comdat {
+entry:
+ %call = tail call i32 @_Z3bari(i32 %x)
+ %0 = load i32, i32* @gv, align 4
+ %add = add nsw i32 %0, %call
+ ret i32 %add
+}
+
+; CHECK: .section .text,"xr",discard,_Z3fooi
+; CHECK: _Z3fooi:
+; CHECK: .section .data,"dw",discard,gv
+; CHECK: gv:
+; CHECK: .long 42
+
+; GNU: .section .text$_Z3fooi,"xr",discard,_Z3fooi
+; GNU: _Z3fooi:
+; GNU: .section .data$gv,"dw",discard,gv
+; GNU: gv:
+; GNU: .long 42
+
+; Make sure the assembler puts the .xdata and .pdata in sections with the right
+; names.
+; GNUOBJ: .text$_Z3fooi
+; GNUOBJ: .xdata$_Z3fooi
+; GNUOBJ: .data$gv
+; GNUOBJ: .pdata$_Z3fooi
+
+declare dso_local i32 @_Z3bari(i32)
+
+attributes #0 = { norecurse uwtable }
+attributes #1 = { inlinehint uwtable }
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