Retrying r91337:

The CIE says that the LSDA point in the FDE section is an "sdata4". That's fine,
but we need it to actually be 4-bytes in the FDE for some platforms. Allow
individual platforms to decide for themselves.

llvm-svn: 93616

4 files changed, 42 insertions, 8 deletions

diff --git a/llvm/include/llvm/Target/TargetMachine.h b/llvm/include/llvm/Target/TargetMachine.h
index 5621e53270b..74dd11fd035 100644
--- a/llvm/include/llvm/Target/TargetMachine.h
+++ b/llvm/include/llvm/Target/TargetMachine.h
@@ -81,6 +81,14 @@ namespace CodeGenOpt {
   };
 }
 
+// Specify if we should encode the LSDA pointer in the FDE as 4- or 8-bytes.
+namespace DwarfLSDAEncoding {
+  enum Encoding {
+    Default,
+    FourByte,
+    EightByte
+  };
+}
 
 //===----------------------------------------------------------------------===//
 ///
@@ -192,6 +200,12 @@ public:
   /// is false.
   static void setAsmVerbosityDefault(bool);
 
+  /// getLSDAEncoding - Returns the LSDA pointer encoding. The choices are
+  /// 4-byte, 8-byte, and target default.
+  virtual DwarfLSDAEncoding::Encoding getLSDAEncoding() const {
+    return DwarfLSDAEncoding::Default;
+  }
+
   /// CodeGenFileType - These enums are meant to be passed into
   /// addPassesToEmitFile to indicate what type of file to emit.
   enum CodeGenFileType {
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfException.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfException.cpp
index d01f300990c..c1d3f4900c3 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfException.cpp
@@ -283,17 +283,28 @@ void DwarfException::EmitFDE(const FunctionEHFrameInfo &EHFrameInfo) {
     if (MMI->getPersonalities()[0] != NULL) {
       bool is4Byte = TD->getPointerSize() == sizeof(int32_t);
 
-      Asm->EmitULEB128Bytes(is4Byte ? 4 : 8);
-      Asm->EOL("Augmentation size");
+      if (Asm->TM.getLSDAEncoding() == DwarfLSDAEncoding::FourByte) {
+        Asm->EmitULEB128Bytes(4);
+        Asm->EOL("Augmentation size");
 
-      if (EHFrameInfo.hasLandingPads)
-        EmitReference("exception", EHFrameInfo.Number, true, false);
-      else {
-        if (is4Byte)
-          Asm->EmitInt32((int)0);
+        if (EHFrameInfo.hasLandingPads)
+          EmitReference("exception", EHFrameInfo.Number, true, true);
         else
-          Asm->EmitInt64((int)0);
+          Asm->EmitInt32((int)0);
+      } else {
+        Asm->EmitULEB128Bytes(is4Byte ? 4 : 8);
+        Asm->EOL("Augmentation size");
+
+        if (EHFrameInfo.hasLandingPads) {
+          EmitReference("exception", EHFrameInfo.Number, true, false);
+        } else {
+          if (is4Byte)
+            Asm->EmitInt32((int)0);
+          else
+            Asm->EmitInt64((int)0);
+        }
       }
+
       Asm->EOL("Language Specific Data Area");
     } else {
       Asm->EmitULEB128Bytes(0);
diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
index 962f0f7be9a..ea21676c3b2 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -249,3 +249,10 @@ void X86TargetMachine::setCodeModelForJIT() {
   else
     setCodeModel(CodeModel::Small);
 }
+
+DwarfLSDAEncoding::Encoding X86TargetMachine::getLSDAEncoding() const {
+  if (Subtarget.isTargetDarwin() && Subtarget.getDarwinVers() > 10)
+    return DwarfLSDAEncoding::FourByte;
+
+  return DwarfLSDAEncoding::Default;
+}
diff --git a/llvm/lib/Target/X86/X86TargetMachine.h b/llvm/lib/Target/X86/X86TargetMachine.h
index 6183e917157..c42aa89ff9b 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.h
+++ b/llvm/lib/Target/X86/X86TargetMachine.h
@@ -62,6 +62,8 @@ public:
     return Subtarget.isTargetELF() ? &ELFWriterInfo : 0;
   }
 
+  virtual DwarfLSDAEncoding::Encoding getLSDAEncoding() const;
+
   // Set up the pass pipeline.
   virtual bool addInstSelector(PassManagerBase &PM, CodeGenOpt::Level OptLevel);
   virtual bool addPreRegAlloc(PassManagerBase &PM, CodeGenOpt::Level OptLevel);