Fix ARM zero-cost exception table (part 4)

[logan]

Summary

This patch splits the class definition of MCELFStreamer into a header file.

[asl]

We definitely need testcases for such huge pile of new functionality.

[logan]

I will be busy these days. I will try to create some test as soon as possible.

[logan]

Just a update: Currently, I am working on a simple disassembler for unwind opcodes (something like llvm-objdump --unwind), so that we can write unit test to check the output. However, it takes longer than I thought.

[logan]

This patch only refactors the code, split MCELFStreamer into a header, so that in the future we can subclass MCELFStreamer for ARM architecture.

Note: This patch is different from the originally uploaded patch. I decided to split the huge patch into several small patches. For the complete picture about what am I working on, please have a look at https://github.com/loganchien/llvm/compare/fix-arm-ehabi

[t.p.northover]

I think this is a change whose time has come, and the details look good to me too.

[asl]

Looks good, please commit

[logan]

Thanks. Committed as 169603.

include/llvm/MC/MCELFStreamer.h

+//===- MCELFStreamer.h - MCStreamer ELF Object File Interface ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MC_MCELFSTREAMER_H
+#define LLVM_MC_MCELFSTREAMER_H
+
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/MC/MCDirectives.h"
+#include "llvm/MC/MCObjectStreamer.h"
+#include "llvm/MC/SectionKind.h"
+
+#include <vector>
+
+#include <stdint.h>
+
+namespace llvm {
+class MCAsmBackend;
+class MCAssembler;
+class MCCodeEmitter;
+class MCExpr;
+class MCInst;
+class MCSymbol;
+class MCSymbolData;
+class raw_ostream;
+
+class MCELFStreamer : public MCObjectStreamer {
+public:
+  MCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+                raw_ostream &OS, MCCodeEmitter *Emitter)
+    : MCObjectStreamer(Context, TAB, OS, Emitter) {}
+
+  MCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+                raw_ostream &OS, MCCodeEmitter *Emitter,
+                MCAssembler *Assembler)
+    : MCObjectStreamer(Context, TAB, OS, Emitter, Assembler) {}
+
+  virtual ~MCELFStreamer();
+
+  /// @name MCStreamer Interface
+  /// @{
+
+  virtual void InitSections();
+  virtual void ChangeSection(const MCSection *Section);
+  virtual void EmitLabel(MCSymbol *Symbol);
+  virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
+  virtual void EmitThumbFunc(MCSymbol *Func);
+  virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
+  virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
+  virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
+  virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
+  virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                unsigned ByteAlignment);
+  virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol);
+  virtual void EmitCOFFSymbolStorageClass(int StorageClass);
+  virtual void EmitCOFFSymbolType(int Type);
+  virtual void EndCOFFSymbolDef();
+
+  virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value);
+
+  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                     unsigned ByteAlignment);
+
+  virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
+                            uint64_t Size = 0, unsigned ByteAlignment = 0);
+  virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
+                              uint64_t Size, unsigned ByteAlignment = 0);
+  virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                             unsigned AddrSpace);
+
+  virtual void EmitFileDirective(StringRef Filename);
+
+  virtual void EmitTCEntry(const MCSymbol &S);
+
+  virtual void FinishImpl();
+  /// @}
+
+private:
+  virtual void EmitInstToFragment(const MCInst &Inst);
+  virtual void EmitInstToData(const MCInst &Inst);
+
+  void fixSymbolsInTLSFixups(const MCExpr *expr);
+
+  struct LocalCommon {
+    MCSymbolData *SD;
+    uint64_t Size;
+    unsigned ByteAlignment;
+  };
+
+  std::vector<LocalCommon> LocalCommons;
+
+  SmallPtrSet<MCSymbol *, 16> BindingExplicitlySet;
+
+
+  void SetSection(StringRef Section, unsigned Type, unsigned Flags,
+                  SectionKind Kind);
+  void SetSectionData();
+  void SetSectionText();
+  void SetSectionBss();
+};
+
+} // end namespace llvm
+
+#endif

lib/MC/MCELFStreamer.cpp

 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCELFStreamer.h"
+
 #include "MCELF.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/StringExtras.h"

 
 using namespace llvm;
 
-namespace {
-class MCELFStreamer : public MCObjectStreamer {
-public:
-  MCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
-                  raw_ostream &OS, MCCodeEmitter *Emitter)
-    : MCObjectStreamer(Context, TAB, OS, Emitter) {}
 
-  MCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
-                raw_ostream &OS, MCCodeEmitter *Emitter,
-                MCAssembler *Assembler)
-    : MCObjectStreamer(Context, TAB, OS, Emitter, Assembler) {}
+inline void MCELFStreamer::SetSection(StringRef Section, unsigned Type,
+                                      unsigned Flags, SectionKind Kind) {
+  SwitchSection(getContext().getELFSection(Section, Type, Flags, Kind));
+}
 
+inline void MCELFStreamer::SetSectionData() {
+  SetSection(".data",
+             ELF::SHT_PROGBITS,
+             ELF::SHF_WRITE | ELF::SHF_ALLOC,
+             SectionKind::getDataRel());
+  EmitCodeAlignment(4, 0);
+}
 
-  ~MCELFStreamer() {}
+inline void MCELFStreamer::SetSectionText() {
+  SetSection(".text",
+             ELF::SHT_PROGBITS,
+             ELF::SHF_EXECINSTR | ELF::SHF_ALLOC,
+             SectionKind::getText());
+  EmitCodeAlignment(4, 0);
+}
 
-  /// @name MCStreamer Interface
-  /// @{
+inline void MCELFStreamer::SetSectionBss() {
+  SetSection(".bss",
+             ELF::SHT_NOBITS,
+             ELF::SHF_WRITE | ELF::SHF_ALLOC,
+             SectionKind::getBSS());
+  EmitCodeAlignment(4, 0);
+}
 
-  virtual void InitSections();
-  virtual void ChangeSection(const MCSection *Section);
-  virtual void EmitLabel(MCSymbol *Symbol);
-  virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
-  virtual void EmitThumbFunc(MCSymbol *Func);
-  virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
-  virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
-  virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
-  virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
-    llvm_unreachable("ELF doesn't support this directive");
-  }
-  virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
-                                unsigned ByteAlignment);
-  virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {
-    llvm_unreachable("ELF doesn't support this directive");
-  }
-
-  virtual void EmitCOFFSymbolStorageClass(int StorageClass) {
-    llvm_unreachable("ELF doesn't support this directive");
-  }
-
-  virtual void EmitCOFFSymbolType(int Type) {
-    llvm_unreachable("ELF doesn't support this directive");
-  }
-
-  virtual void EndCOFFSymbolDef() {
-    llvm_unreachable("ELF doesn't support this directive");
-  }
-
-  virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
-     MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
-     SD.setSize(Value);
-  }
-
-  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
-                                     unsigned ByteAlignment);
-
-  virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
-                            uint64_t Size = 0, unsigned ByteAlignment = 0) {
-    llvm_unreachable("ELF doesn't support this directive");
-  }
-  virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
-                              uint64_t Size, unsigned ByteAlignment = 0) {
-    llvm_unreachable("ELF doesn't support this directive");
-  }
-  virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
-                             unsigned AddrSpace);
-
-  virtual void EmitFileDirective(StringRef Filename);
-
-  virtual void EmitTCEntry(const MCSymbol &S);
-
-  virtual void FinishImpl();
-
-private:
-  virtual void EmitInstToFragment(const MCInst &Inst);
-  virtual void EmitInstToData(const MCInst &Inst);
-
-  void fixSymbolsInTLSFixups(const MCExpr *expr);
-
-  struct LocalCommon {
-    MCSymbolData *SD;
-    uint64_t Size;
-    unsigned ByteAlignment;
-  };
-  std::vector<LocalCommon> LocalCommons;
-
-  SmallPtrSet<MCSymbol *, 16> BindingExplicitlySet;
-  /// @}
-  void SetSection(StringRef Section, unsigned Type, unsigned Flags,
-                  SectionKind Kind) {
-    SwitchSection(getContext().getELFSection(Section, Type, Flags, Kind));
-  }
-
-  void SetSectionData() {
-    SetSection(".data", ELF::SHT_PROGBITS,
-               ELF::SHF_WRITE |ELF::SHF_ALLOC,
-               SectionKind::getDataRel());
-    EmitCodeAlignment(4, 0);
-  }
-  void SetSectionText() {
-    SetSection(".text", ELF::SHT_PROGBITS,
-               ELF::SHF_EXECINSTR |
-               ELF::SHF_ALLOC, SectionKind::getText());
-    EmitCodeAlignment(4, 0);
-  }
-  void SetSectionBss() {
-    SetSection(".bss", ELF::SHT_NOBITS,
-               ELF::SHF_WRITE |
-               ELF::SHF_ALLOC, SectionKind::getBSS());
-    EmitCodeAlignment(4, 0);
-  }
-};
+MCELFStreamer::~MCELFStreamer() {
 }
 
 void MCELFStreamer::InitSections() {

   SD.setSize(MCConstantExpr::Create(Size, getContext()));
 }
 
+void MCELFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
+  MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
+  SD.setSize(Value);
+}
+
 void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                                           unsigned ByteAlignment) {
   // FIXME: Should this be caught and done earlier?

     S->getAssembler().setNoExecStack(true);
   return S;
 }
+
+void MCELFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
+  llvm_unreachable("ELF doesn't support this directive");
+}
+
+void MCELFStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {
+  llvm_unreachable("ELF doesn't support this directive");
+}
+
+void MCELFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
+  llvm_unreachable("ELF doesn't support this directive");
+}
+
+void MCELFStreamer::EmitCOFFSymbolType(int Type) {
+  llvm_unreachable("ELF doesn't support this directive");
+}
+
+void MCELFStreamer::EndCOFFSymbolDef() {
+  llvm_unreachable("ELF doesn't support this directive");
+}
+
+void MCELFStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
+                                 uint64_t Size, unsigned ByteAlignment) {
+  llvm_unreachable("ELF doesn't support this directive");
+}
+
+void MCELFStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
+                                   uint64_t Size, unsigned ByteAlignment) {
+  llvm_unreachable("ELF doesn't support this directive");
+}