6 files changed, 40 insertions, 2 deletions
diff --git a/include/llvm/Target/TargetLoweringObjectFile.h b/include/llvm/Target/TargetLoweringObjectFile.h
index 819709fa20..5456dd0700 100644
--- a/include/llvm/Target/TargetLoweringObjectFile.h
+++ b/include/llvm/Target/TargetLoweringObjectFile.h
@@ -92,6 +92,11 @@ protected:
   // information for a TLS variable, it'll go here.
   const MCSection *TLSExtraDataSection;
   
+  /// CommDirectiveSupportsAlignment - True if .comm supports alignment.  This
+  /// is a hack for as long as we support 10.4 Tiger, whose assembler doesn't
+  /// support alignment on comm.
+  bool CommDirectiveSupportsAlignment;
+  
   /// SupportsWeakEmptyEHFrame - True if target object file supports a
   /// weak_definition of constant 0 for an omitted EH frame.
   bool SupportsWeakOmittedEHFrame;
@@ -128,6 +133,10 @@ public:
     return SupportsWeakOmittedEHFrame;
   }
   
+  bool getCommDirectiveSupportsAlignment() const {
+    return CommDirectiveSupportsAlignment;
+  }
+
   const MCSection *getTextSection() const { return TextSection; }
   const MCSection *getDataSection() const { return DataSection; }
   const MCSection *getBSSSection() const { return BSSSection; }
diff --git a/include/llvm/Target/TargetMachine.h b/include/llvm/Target/TargetMachine.h
index 426338ff8d..35f2658acd 100644
--- a/include/llvm/Target/TargetMachine.h
+++ b/include/llvm/Target/TargetMachine.h
@@ -280,6 +280,8 @@ private:
   
 public:
   
+  const std::string &getTargetTriple() const { return TargetTriple; }
+  
   /// addPassesToEmitFile - Add passes to the specified pass manager to get the
   /// specified file emitted.  Typically this will involve several steps of code
   /// generation.  If OptLevel is None, the code generator should emit code as
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index ee6d321763..0de2021133 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -282,8 +282,12 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
     
     // Handle common symbols.
     if (GVKind.isCommon()) {
+      unsigned Align = 1 << AlignLog;
+      if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
+        Align = 0;
+          
       // .comm _foo, 42, 4
-      OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
+      OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
       return;
     }
     
@@ -301,11 +305,15 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
       OutStreamer.EmitLocalCommonSymbol(GVSym, Size);
       return;
     }
+
+    unsigned Align = 1 << AlignLog;
+    if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
+      Align = 0;
     
     // .local _foo
     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
     // .comm _foo, 42, 4
-    OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
+    OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
     return;
   }
   
diff --git a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index f1e10eec72..4afdc3ddef 100644
--- a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -33,6 +33,7 @@
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/Triple.h"
 using namespace llvm;
 using namespace dwarf;
 
@@ -450,6 +451,19 @@ void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
   IsFunctionEHSymbolGlobal = true;
   IsFunctionEHFrameSymbolPrivate = false;
   SupportsWeakOmittedEHFrame = false;
+
+  Triple T(((LLVMTargetMachine&)TM).getTargetTriple());
+  if (T.getOS() == Triple::Darwin) {
+    switch (T.getDarwinMajorNumber()) {
+    case 7:  // 10.3 Panther.
+    case 8:  // 10.4 Tiger.
+      CommDirectiveSupportsAlignment = false;
+      break;
+    case 9:   // 10.5 Leopard.
+    case 10:  // 10.6 SnowLeopard.
+      break;
+    }
+  }
   
   TargetLoweringObjectFile::Initialize(Ctx, TM);
 
diff --git a/lib/Target/TargetLoweringObjectFile.cpp b/lib/Target/TargetLoweringObjectFile.cpp
index dd7b532bbf..0e67fe5d98 100644
--- a/lib/Target/TargetLoweringObjectFile.cpp
+++ b/lib/Target/TargetLoweringObjectFile.cpp
@@ -45,6 +45,7 @@ TargetLoweringObjectFile::TargetLoweringObjectFile() : Ctx(0) {
   LSDASection = 0;
   EHFrameSection = 0;
 
+  CommDirectiveSupportsAlignment = true;
   DwarfAbbrevSection = 0;
   DwarfInfoSection = 0;
   DwarfLineSection = 0;
diff --git a/test/CodeGen/PowerPC/align.ll b/test/CodeGen/PowerPC/align.ll
index 109a83726e..0797ca8d0b 100644
--- a/test/CodeGen/PowerPC/align.ll
+++ b/test/CodeGen/PowerPC/align.ll
@@ -1,5 +1,6 @@
 ; RUN: llc < %s -mtriple=powerpc-linux-gnu | FileCheck %s -check-prefix=ELF
 ; RUN: llc < %s -mtriple=powerpc-apple-darwin9 | FileCheck %s -check-prefix=DARWIN
+; RUN: llc < %s -mtriple=powerpc-apple-darwin8 | FileCheck %s -check-prefix=DARWIN8
 
 @a = global i1 true
 ; no alignment
@@ -40,3 +41,6 @@
 @bar = common global [75 x i8] zeroinitializer, align 128
 ;ELF: .comm bar,75,128
 ;DARWIN: .comm _bar,75,7
+
+;; Darwin8 doesn't support aligned comm.  Just miscompile this.
+; DARWIN8: .comm _bar,75 ;