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
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 3d3abc2..baf11a7 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 @@
   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 @@
 
       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 68be2ee..aff86bb 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 @@
   // 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 @@
 
   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 @@
 
   // 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.