[llvm] r173939 - Override virtual function for ARM EH directives.
Logan Chien
tzuhsiang.chien at gmail.com
Wed Jan 30 07:39:05 PST 2013
Author: logan
Date: Wed Jan 30 09:39:04 2013
New Revision: 173939
URL: http://llvm.org/viewvc/llvm-project?rev=173939&view=rev
Log:
Override virtual function for ARM EH directives.
Modified:
llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
Modified: llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp?rev=173939&r1=173938&r2=173939&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp (original)
+++ llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp Wed Jan 30 09:39:04 2013
@@ -13,6 +13,7 @@
//
//===----------------------------------------------------------------------===//
+#include "ARMUnwindOp.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Twine.h"
#include "llvm/MC/MCAsmBackend.h"
@@ -56,11 +57,25 @@ public:
ARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
raw_ostream &OS, MCCodeEmitter *Emitter, bool IsThumb)
: MCELFStreamer(Context, TAB, OS, Emitter),
- IsThumb(IsThumb), MappingSymbolCounter(0), LastEMS(EMS_None) {
+ IsThumb(IsThumb), MappingSymbolCounter(0), LastEMS(EMS_None),
+ ExTab(0), FnStart(0), Personality(0), CantUnwind(false) {
}
~ARMELFStreamer() {}
+ // ARM exception handling directives
+ virtual void EmitFnStart();
+ virtual void EmitFnEnd();
+ virtual void EmitCantUnwind();
+ virtual void EmitPersonality(const MCSymbol *Per);
+ virtual void EmitHandlerData();
+ virtual void EmitSetFP(unsigned NewFpReg,
+ unsigned NewSpReg,
+ int64_t Offset = 0);
+ virtual void EmitPad(int64_t Offset);
+ virtual void EmitRegSave(const SmallVectorImpl<unsigned> &RegList,
+ bool isVector);
+
virtual void ChangeSection(const MCSection *Section) {
// We have to keep track of the mapping symbol state of any sections we
// use. Each one should start off as EMS_None, which is provided as the
@@ -172,6 +187,15 @@ private:
SD.setFlags(SD.getFlags() | ELF_Other_ThumbFunc);
}
+ // Helper functions for ARM exception handling directives
+ void Reset();
+
+ void EmitPersonalityFixup(StringRef Name);
+
+ void SwitchToEHSection(const char *Prefix, unsigned Type, unsigned Flags,
+ SectionKind Kind, const MCSymbol &Fn);
+ void SwitchToExTabSection(const MCSymbol &FnStart);
+ void SwitchToExIdxSection(const MCSymbol &FnStart);
bool IsThumb;
int64_t MappingSymbolCounter;
@@ -179,10 +203,200 @@ private:
DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols;
ElfMappingSymbol LastEMS;
- /// @}
+ // ARM Exception Handling Frame Information
+ MCSymbol *ExTab;
+ MCSymbol *FnStart;
+ const MCSymbol *Personality;
+ bool CantUnwind;
};
}
+inline void ARMELFStreamer::SwitchToEHSection(const char *Prefix,
+ unsigned Type,
+ unsigned Flags,
+ SectionKind Kind,
+ const MCSymbol &Fn) {
+ const MCSectionELF &FnSection =
+ static_cast<const MCSectionELF &>(Fn.getSection());
+
+ // Create the name for new section
+ StringRef FnSecName(FnSection.getSectionName());
+ SmallString<128> EHSecName(Prefix);
+ if (FnSecName != ".text") {
+ EHSecName += FnSecName;
+ }
+
+ // Get .ARM.extab or .ARM.exidx section
+ const MCSectionELF *EHSection = NULL;
+ if (const MCSymbol *Group = FnSection.getGroup()) {
+ EHSection = getContext().getELFSection(
+ EHSecName, Type, Flags | ELF::SHF_GROUP, Kind,
+ FnSection.getEntrySize(), Group->getName());
+ } else {
+ EHSection = getContext().getELFSection(EHSecName, Type, Flags, Kind);
+ }
+ assert(EHSection);
+
+ // Switch to .ARM.extab or .ARM.exidx section
+ SwitchSection(EHSection);
+ EmitCodeAlignment(4, 0);
+}
+
+inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
+ SwitchToEHSection(".ARM.extab",
+ ELF::SHT_PROGBITS,
+ ELF::SHF_ALLOC,
+ SectionKind::getDataRel(),
+ FnStart);
+}
+
+inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
+ SwitchToEHSection(".ARM.exidx",
+ ELF::SHT_ARM_EXIDX,
+ ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
+ SectionKind::getDataRel(),
+ FnStart);
+}
+
+void ARMELFStreamer::Reset() {
+ ExTab = NULL;
+ FnStart = NULL;
+ Personality = NULL;
+ CantUnwind = false;
+}
+
+// Add the R_ARM_NONE fixup at the same position
+void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
+ const MCSymbol *PersonalitySym = getContext().GetOrCreateSymbol(Name);
+
+ const MCSymbolRefExpr *PersonalityRef =
+ MCSymbolRefExpr::Create(PersonalitySym,
+ MCSymbolRefExpr::VK_ARM_NONE,
+ getContext());
+
+ AddValueSymbols(PersonalityRef);
+ MCDataFragment *DF = getOrCreateDataFragment();
+ DF->getFixups().push_back(
+ MCFixup::Create(DF->getContents().size(), PersonalityRef,
+ MCFixup::getKindForSize(4, false)));
+}
+
+void ARMELFStreamer::EmitFnStart() {
+ assert(FnStart == 0);
+ FnStart = getContext().CreateTempSymbol();
+ EmitLabel(FnStart);
+}
+
+void ARMELFStreamer::EmitFnEnd() {
+ assert(FnStart && ".fnstart must preceeds .fnend");
+
+ // Emit unwind opcodes if there is no .handlerdata directive
+ int PersonalityIndex = -1;
+ if (!ExTab && !CantUnwind) {
+ // For __aeabi_unwind_cpp_pr1, we have to emit opcodes in .ARM.extab.
+ SwitchToExTabSection(*FnStart);
+
+ // Create .ARM.extab label for offset in .ARM.exidx
+ ExTab = getContext().CreateTempSymbol();
+ EmitLabel(ExTab);
+
+ PersonalityIndex = 1;
+
+ uint32_t Entry = 0;
+ uint32_t NumExtraEntryWords = 0;
+ Entry |= NumExtraEntryWords << 24;
+ Entry |= (EHT_COMPACT | PersonalityIndex) << 16;
+
+ // TODO: This should be generated according to .save, .vsave, .setfp
+ // directives. Currently, we are simply generating FINISH opcode.
+ Entry |= UNWIND_OPCODE_FINISH << 8;
+ Entry |= UNWIND_OPCODE_FINISH;
+
+ EmitIntValue(Entry, 4, 0);
+ }
+
+ // Emit the exception index table entry
+ SwitchToExIdxSection(*FnStart);
+
+ if (PersonalityIndex == 1)
+ EmitPersonalityFixup("__aeabi_unwind_cpp_pr1");
+
+ const MCSymbolRefExpr *FnStartRef =
+ MCSymbolRefExpr::Create(FnStart,
+ MCSymbolRefExpr::VK_ARM_PREL31,
+ getContext());
+
+ EmitValue(FnStartRef, 4, 0);
+
+ if (CantUnwind) {
+ EmitIntValue(EXIDX_CANTUNWIND, 4, 0);
+ } else {
+ const MCSymbolRefExpr *ExTabEntryRef =
+ MCSymbolRefExpr::Create(ExTab,
+ MCSymbolRefExpr::VK_ARM_PREL31,
+ getContext());
+ EmitValue(ExTabEntryRef, 4, 0);
+ }
+
+ // Clean exception handling frame information
+ Reset();
+}
+
+void ARMELFStreamer::EmitCantUnwind() {
+ CantUnwind = true;
+}
+
+void ARMELFStreamer::EmitHandlerData() {
+ SwitchToExTabSection(*FnStart);
+
+ // Create .ARM.extab label for offset in .ARM.exidx
+ assert(!ExTab);
+ ExTab = getContext().CreateTempSymbol();
+ EmitLabel(ExTab);
+
+ // Emit Personality
+ assert(Personality && ".personality directive must preceed .handlerdata");
+
+ const MCSymbolRefExpr *PersonalityRef =
+ MCSymbolRefExpr::Create(Personality,
+ MCSymbolRefExpr::VK_ARM_PREL31,
+ getContext());
+
+ EmitValue(PersonalityRef, 4, 0);
+
+ // Emit unwind opcodes
+ uint32_t Entry = 0;
+ uint32_t NumExtraEntryWords = 0;
+
+ // TODO: This should be generated according to .save, .vsave, .setfp
+ // directives. Currently, we are simply generating FINISH opcode.
+ Entry |= NumExtraEntryWords << 24;
+ Entry |= UNWIND_OPCODE_FINISH << 16;
+ Entry |= UNWIND_OPCODE_FINISH << 8;
+ Entry |= UNWIND_OPCODE_FINISH;
+
+ EmitIntValue(Entry, 4, 0);
+}
+
+void ARMELFStreamer::EmitPersonality(const MCSymbol *Per) {
+ Personality = Per;
+}
+
+void ARMELFStreamer::EmitSetFP(unsigned NewFpReg,
+ unsigned NewSpReg,
+ int64_t Offset) {
+ // TODO: Not implemented
+}
+
+void ARMELFStreamer::EmitPad(int64_t Offset) {
+ // TODO: Not implemented
+}
+
+void ARMELFStreamer::EmitRegSave(const SmallVectorImpl<unsigned> &RegList,
+ bool IsVector) {
+ // TODO: Not implemented
+}
+
namespace llvm {
MCELFStreamer* createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
raw_ostream &OS, MCCodeEmitter *Emitter,
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