Add 129518 back with a fix for when we are producing eh just because of debug info.

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@129571 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 86 insertions, 19 deletions

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 3d3abc2fed..baf11a77db 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/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());
diff --git a/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
index 68be2eed8f..8e4cf467b4 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
+++ b/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);
   }
 }
 
@@ -77,7 +83,7 @@ void DwarfCFIException::BeginFunction(const MachineFunction *MF) {
   shouldEmitTable = !MMI->getLandingPads().empty();
 
   // See if we need frame move info.
-  shouldEmitMoves =
+  shouldEmitMoves = MMI->hasDebugInfo() ||
     !Asm->MF->getFunction()->doesNotThrow() || UnwindTablesMandatory;
 
   if (shouldEmitMoves || shouldEmitTable)
@@ -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.
diff --git a/lib/Target/TargetLoweringObjectFile.cpp b/lib/Target/TargetLoweringObjectFile.cpp
index 5d34c7d7fa..7eeec5dda4 100644
--- a/lib/Target/TargetLoweringObjectFile.cpp
+++ b/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:
diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp
index dee27a0336..df20429bcc 100644
--- a/lib/Target/X86/X86FrameLowering.cpp
+++ b/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);
diff --git a/lib/Target/X86/X86MCAsmInfo.cpp b/lib/Target/X86/X86MCAsmInfo.cpp
index 6686214e06..6295189772 100644
--- a/lib/Target/X86/X86MCAsmInfo.cpp
+++ b/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.