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

3 files changed, 15 insertions, 3 deletions

diff --git a/llvm/lib/Target/TargetLoweringObjectFile.cpp b/llvm/lib/Target/TargetLoweringObjectFile.cpp
index 5d34c7d7fa3..7eeec5dda46 100644
--- a/llvm/lib/Target/TargetLoweringObjectFile.cpp
+++ b/llvm/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/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
index dee27a0336d..df20429bcc7 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/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/llvm/lib/Target/X86/X86MCAsmInfo.cpp b/llvm/lib/Target/X86/X86MCAsmInfo.cpp
index 6686214e06f..62951897724 100644
--- a/llvm/lib/Target/X86/X86MCAsmInfo.cpp
+++ b/llvm/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.