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.

llvm-svn: 129571

2 files changed, 71 insertions, 16 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 3d3abc2fed2..baf11a77db3 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/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/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
index 68be2eed8f0..8e4cf467b40 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
+++ b/llvm/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.