Change ELF systems to use CFI for producing the EH tables. This reduces the

size of the clang binary in Debug builds from 690MB to 679MB.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129518 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/AsmPrinter.h

@@ -183,6 +183,8 @@ namespace llvm {
     /// function.
     void EmitFunctionBody();
 
+    void emitPrologLabel(const MachineInstr &MI);
+
     /// EmitConstantPool - Print to the current output stream assembly
     /// representations of the constants in the constant pool MCP. This is
     /// used to print out constants which have been "spilled to memory" by

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -33,6 +33,7 @@
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Target/Mangler.h"
+#include "llvm/Target/TargetAsmInfo.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetLowering.h"
@@ -624,6 +625,45 @@ static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
   return true;
 }
 
+void AsmPrinter::emitPrologLabel(const MachineInstr &MI) {
+  MCSymbol *Label = MI.getOperand(0).getMCSymbol();
+  if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI) {
+    OutStreamer.EmitLabel(Label);
+    return;
+  }
+
+  const MachineFunction &MF = *MI.getParent()->getParent();
+  MachineModuleInfo &MMI = MF.getMMI();
+  std::vector<MachineMove> &Moves = MMI.getFrameMoves();
+  const MachineMove *Move = NULL;
+  for (std::vector<MachineMove>::iterator I = Moves.begin(),
+         E = Moves.end(); I != E; ++I) {
+    if (I->getLabel() == Label) {
+      Move = &*I;
+      break;
+    }
+  }
+  assert(Move);
+
+  const MachineLocation &Dst = Move->getDestination();
+  const MachineLocation &Src = Move->getSource();
+  const TargetAsmInfo &AsmInfo = OutContext.getTargetAsmInfo();
+  if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
+    if (Src.getReg() == MachineLocation::VirtualFP)
+      OutStreamer.EmitCFIDefCfaOffset(-Src.getOffset());
+    else {
+      unsigned Reg = AsmInfo.getDwarfRegNum(Src.getReg(), true);
+      OutStreamer.EmitCFIDefCfa(Reg, -Src.getOffset());
+    }
+  } else if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
+    unsigned Reg = AsmInfo.getDwarfRegNum(Dst.getReg(), true);
+    OutStreamer.EmitCFIDefCfaRegister(Reg);
+  } else {
+    unsigned Reg = AsmInfo.getDwarfRegNum(Src.getReg(), true);
+    OutStreamer.EmitCFIOffset(Reg, -Dst.getOffset());
+  }
+}
+
 /// EmitFunctionBody - This method emits the body and trailer for a
 /// function.
 void AsmPrinter::EmitFunctionBody() {
@@ -660,6 +700,9 @@ void AsmPrinter::EmitFunctionBody() {
 
       switch (II->getOpcode()) {
       case TargetOpcode::PROLOG_LABEL:
+        emitPrologLabel(*II);
+        break;
+
       case TargetOpcode::EH_LABEL:
       case TargetOpcode::GC_LABEL:
         OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol());

lib/CodeGen/AsmPrinter/DwarfCFIException.cpp

@@ -32,6 +32,7 @@
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Support/Dwarf.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FormattedStream.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
@@ -60,11 +61,16 @@ void DwarfCFIException::EndModule() {
   // Begin eh frame section.
   Asm->OutStreamer.SwitchSection(TLOF.getEHFrameSection());
 
+  if ((PerEncoding & 0x70) != dwarf::DW_EH_PE_pcrel)
+    return;
+
   // Emit references to all used personality functions
   const std::vector<const Function*> &Personalities = MMI->getPersonalities();
   for (size_t i = 0, e = Personalities.size(); i != e; ++i) {
     Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("personality", i));
-    Asm->EmitReference(Personalities[i], PerEncoding);
+    const MCSymbol *Sym = Asm->Mang->getSymbol(Personalities[i]);
+    unsigned Size = Asm->TM.getTargetData()->getPointerSize();
+    Asm->OutStreamer.EmitSymbolValue(Sym, Size);
   }
 }
 
@@ -87,17 +93,9 @@ void DwarfCFIException::BeginFunction(const MachineFunction *MF) {
 
   shouldEmitTableModule |= shouldEmitTable;
 
-  if (shouldEmitMoves) {
-    const TargetFrameLowering *TFL = Asm->TM.getFrameLowering();
+  if (shouldEmitMoves || shouldEmitTable)
     Asm->OutStreamer.EmitCFIStartProc();
 
-    // Indicate locations of general callee saved registers in frame.
-    std::vector<MachineMove> Moves;
-    TFL->getInitialFrameState(Moves);
-    Asm->EmitCFIFrameMoves(Moves);
-    Asm->EmitCFIFrameMoves(MMI->getFrameMoves());
-  }
-
   if (!shouldEmitTable)
     return;
 
@@ -112,11 +110,25 @@ void DwarfCFIException::BeginFunction(const MachineFunction *MF) {
 
   // Indicate personality routine, if any.
   unsigned PerEncoding = TLOF.getPersonalityEncoding();
-  if (PerEncoding != dwarf::DW_EH_PE_omit &&
-      MMI->getPersonalities()[MMI->getPersonalityIndex()])
-    Asm->OutStreamer.EmitCFIPersonality(Asm->GetTempSymbol("personality",
-                                                    MMI->getPersonalityIndex()),
-                                        PerEncoding);
+  const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()];
+  if (PerEncoding == dwarf::DW_EH_PE_omit || !Per)
+    return;
+
+  const MCSymbol *Sym;
+  switch (PerEncoding & 0x70) {
+  default:
+    report_fatal_error("We do not support this DWARF encoding yet!");
+  case dwarf::DW_EH_PE_absptr: {
+    Sym = Asm->Mang->getSymbol(Per);
+    break;
+  }
+  case dwarf::DW_EH_PE_pcrel: {
+    Sym = Asm->GetTempSymbol("personality",
+                             MMI->getPersonalityIndex());
+    break;
+  }
+  }
+  Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding);
 }
 
 /// EndFunction - Gather and emit post-function exception information.

lib/Target/TargetLoweringObjectFile.cpp

@@ -314,7 +314,7 @@ getExprForDwarfReference(const MCSymbol *Sym, Mangler *Mang,
                          MCStreamer &Streamer) const {
   const MCExpr *Res = MCSymbolRefExpr::Create(Sym, getContext());
 
-  switch (Encoding & 0xF0) {
+  switch (Encoding & 0x70) {
   default:
     report_fatal_error("We do not support this DWARF encoding yet!");
   case dwarf::DW_EH_PE_absptr:

lib/Target/X86/X86FrameLowering.cpp

@@ -22,6 +22,7 @@
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/MC/MCAsmInfo.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Support/CommandLine.h"
@@ -476,6 +477,15 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
         .addReg(StackPtr);
 
     if (needsFrameMoves) {
+      const MCAsmInfo &MAI = MMI.getContext().getAsmInfo();
+      if (MAI.getExceptionHandlingType() == ExceptionHandling::DwarfCFI) {
+        MCSymbol *FrameLabel0 = MMI.getContext().CreateTempSymbol();
+        BuildMI(MBB, MBBI, DL, TII.get(X86::PROLOG_LABEL)).addSym(FrameLabel0);
+        MachineLocation FPSrc0(FramePtr);
+        MachineLocation FPDst0(FramePtr, -2 * stackGrowth);
+        Moves.push_back(MachineMove(FrameLabel0, FPDst0, FPSrc0));
+      }
+
       // Mark effective beginning of when frame pointer becomes valid.
       MCSymbol *FrameLabel = MMI.getContext().CreateTempSymbol();
       BuildMI(MBB, MBBI, DL, TII.get(X86::PROLOG_LABEL)).addSym(FrameLabel);
@@ -615,7 +625,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
     emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit,
                  TII, *RegInfo);
 
-  if ((NumBytes || PushedRegs) && needsFrameMoves) {
+  if (( (!HasFP && NumBytes) || PushedRegs) && needsFrameMoves) {
     // Mark end of stack pointer adjustment.
     MCSymbol *Label = MMI.getContext().CreateTempSymbol();
     BuildMI(MBB, MBBI, DL, TII.get(X86::PROLOG_LABEL)).addSym(Label);

lib/Target/X86/X86MCAsmInfo.cpp

@@ -89,7 +89,9 @@ X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
   SupportsDebugInformation = true;
 
   // Exceptions handling
-  ExceptionsType = ExceptionHandling::DwarfTable;
+  ExceptionsType = ExceptionHandling::DwarfCFI;
+
+  DwarfRequiresFrameSection = false;
 
   // OpenBSD has buggy support for .quad in 32-bit mode, just split into two
   // .words.

test/CodeGen/X86/2007-05-05-Personality.ll

@@ -1,4 +1,7 @@
-; RUN: llc < %s -mtriple=i686-pc-linux-gnu -o - | grep zPL
+; RUN: llc < %s -mtriple=i686-pc-linux-gnu -o - | FileCheck %s
+
+; CHECK: .cfi_lsda 0, .Lexception0
+; CHECK: .cfi_personality 0, __gnat_eh_personality
 
 @error = external global i8		; <i8*> [#uses=2]
 

test/CodeGen/X86/2008-12-12-PrivateEHSymbol.ll

@@ -1,12 +0,0 @@
-; RUN: llc < %s -march=x86-64 -mtriple=x86_64-unknown-linux-gnu | grep ^.L_Z1fv.eh
-; RUN: llc < %s -march=x86    -mtriple=i686-unknown-linux-gnu | grep ^.L_Z1fv.eh
-; RUN: llc < %s -march=x86-64 -mtriple=x86_64-apple-darwin9 | grep ^__Z1fv.eh
-; RUN: llc < %s -march=x86    -mtriple=i386-apple-darwin9 | grep ^__Z1fv.eh
-
-define void @_Z1fv() {
-entry:
-	br label %return
-
-return:
-	ret void
-}

test/CodeGen/X86/aliases.ll

@@ -1,6 +1,4 @@
 ; RUN: llc < %s -mtriple=i686-pc-linux-gnu -asm-verbose=false -o %t
-; RUN: grep { = } %t   | count 16
-; RUN: grep set %t   | count 18
 ; RUN: grep globl %t | count 6
 ; RUN: grep weak %t  | count 1
 ; RUN: grep hidden %t | count 1