the latest assembler that runs on powerpc 10.4 machines doesn't

support aligned comm.  Detect when compiling for 10.4 and don't
emit an alignment for comm.  THis will hopefully fix PR8198.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114817 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 40 insertions, 2 deletions

diff --git a/include/llvm/Target/TargetLoweringObjectFile.h b/include/llvm/Target/TargetLoweringObjectFile.h
index 819709f..5456dd0 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 426338f..35f2658 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 ee6d321..0de2021 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 f1e10ee..4afdc3d 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 dd7b532..0e67fe5 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 109a837..0797ca8 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 ;