Add new function attribute - noredzone.

Update code generator to use this attribute and remove DisableRedZone target option.
Update llc to set this attribute when -disable-red-zone command line option is used.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72894 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Attributes.h

@@ -54,13 +54,15 @@ const Attributes Alignment = 31<<16; ///< Alignment of parameter (5 bits)
                                      // stored as log2 of alignment with +1 bias
                                      // 0 means unaligned different from align 1
 const Attributes NoCapture = 1<<21; ///< Function creates no aliases of pointer
+const Attributes NoRedZone = 1<<22; /// disable redzone
 
 /// @brief Attributes that only apply to function parameters.
 const Attributes ParameterOnly = ByVal | Nest | StructRet | NoCapture;
 
 /// @brief Attributes that only apply to function.
 const Attributes FunctionOnly = NoReturn | NoUnwind | ReadNone | ReadOnly | 
-  NoInline | AlwaysInline | OptimizeForSize | StackProtect | StackProtectReq;
+  NoInline | AlwaysInline | OptimizeForSize | StackProtect | StackProtectReq |
+  NoRedZone;
 
 /// @brief Parameter attributes that do not apply to vararg call arguments.
 const Attributes VarArgsIncompatible = StructRet;

include/llvm/Target/TargetOptions.h

@@ -117,10 +117,6 @@ namespace llvm {
   /// wth earlier copy coalescing.
   extern bool StrongPHIElim;
 
-  /// DisableRedZone - This flag disables use of the "Red Zone" on
-  /// targets which would otherwise have one.
-  extern bool DisableRedZone;
-
 } // End llvm namespace
 
 #endif

lib/AsmParser/LLLexer.cpp

@@ -547,6 +547,7 @@ lltok::Kind LLLexer::LexIdentifier() {
   KEYWORD(optsize);
   KEYWORD(ssp);
   KEYWORD(sspreq);
+  KEYWORD(noredzone);
 
   KEYWORD(type);
   KEYWORD(opaque);

lib/AsmParser/LLParser.cpp

@@ -730,7 +730,7 @@ bool LLParser::ParseOptionalAttrs(unsigned &Attrs, unsigned AttrKind) {
     case lltok::kw_optsize:      Attrs |= Attribute::OptimizeForSize; break;
     case lltok::kw_ssp:          Attrs |= Attribute::StackProtect; break;
     case lltok::kw_sspreq:       Attrs |= Attribute::StackProtectReq; break;
-
+    case lltok::kw_noredzone:    Attrs |= Attribute::NoRedZone; break;
         
     case lltok::kw_align: {
       unsigned Alignment;

lib/AsmParser/LLToken.h

@@ -80,6 +80,7 @@ namespace lltok {
     kw_optsize,
     kw_ssp,
     kw_sspreq,
+    kw_noredzone,
 
     kw_type,
     kw_opaque,

lib/Target/PowerPC/PPCRegisterInfo.cpp

@@ -908,6 +908,7 @@ void PPCRegisterInfo::determineFrameLayout(MachineFunction &MF) const {
   // If we are a leaf function, and use up to 224 bytes of stack space,
   // don't have a frame pointer, calls, or dynamic alloca then we do not need
   // to adjust the stack pointer (we fit in the Red Zone).
+  bool DisableRedZone = MF.getFunction()->hasFnAttr(Attribute::NoRedZone);
   if (!DisableRedZone &&
       FrameSize <= 224 &&                          // Fits in red zone.
       !MFI->hasVarSizedObjects() &&                // No dynamic alloca.

lib/Target/TargetMachine.cpp

@@ -41,7 +41,6 @@ namespace llvm {
   bool RealignStack;
   bool DisableJumpTables;
   bool StrongPHIElim;
-  bool DisableRedZone;
   bool AsmVerbosityDefault(false);
 }
 
@@ -163,11 +162,6 @@ EnableStrongPHIElim(cl::Hidden, "strong-phi-elim",
   cl::desc("Use strong PHI elimination."),
   cl::location(StrongPHIElim),
   cl::init(false));
-static cl::opt<bool, true>
-DisableRedZoneOption("disable-red-zone",
-  cl::desc("Do not emit code that uses the red zone."),
-  cl::location(DisableRedZone),
-  cl::init(false));
 
 //---------------------------------------------------------------------------
 // TargetMachine Class

lib/Target/X86/X86RegisterInfo.cpp

@@ -751,6 +751,7 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
   // function, and use up to 128 bytes of stack space, don't have a frame
   // pointer, calls, or dynamic alloca then we do not need to adjust the
   // stack pointer (we fit in the Red Zone).
+  bool DisableRedZone = Fn->hasFnAttr(Attribute::NoRedZone);
   if (Is64Bit && !DisableRedZone &&
       !needsStackRealignment(MF) &&
       !MFI->hasVarSizedObjects() &&                // No dynamic alloca.

lib/VMCore/Attributes.cpp

@@ -59,6 +59,8 @@ std::string Attribute::getAsString(Attributes Attrs) {
     Result += "ssp ";
   if (Attrs & Attribute::StackProtectReq)
     Result += "sspreq ";
+  if (Attrs & Attribute::NoRedZone)
+    Result += "noredzone ";
   if (Attrs & Attribute::Alignment) {
     Result += "align ";
     Result += utostr(Attribute::getAlignmentFromAttrs(Attrs));

test/CodeGen/X86/red-zone2.ll

@@ -0,0 +1,9 @@
+; RUN: llvm-as < %s | llc -march=x86-64 > %t
+; RUN: grep subq %t | count 1
+; RUN: grep addq %t | count 1
+
+define x86_fp80 @f0(float %f) nounwind readnone noredzone {
+entry:
+	%0 = fpext float %f to x86_fp80		; <x86_fp80> [#uses=1]
+	ret x86_fp80 %0
+}

tools/llc/llc.cpp

@@ -100,6 +100,11 @@ cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
                        cl::desc("Do not verify input module"));
 
 
+static cl::opt<bool>
+DisableRedZone("disable-red-zone",
+  cl::desc("Do not emit code that uses the red zone."),
+  cl::init(false));
+
 // GetFileNameRoot - Helper function to get the basename of a filename.
 static inline std::string
 GetFileNameRoot(const std::string &InputFilename) {
@@ -336,8 +341,11 @@ int main(int argc, char **argv) {
     // Run our queue of passes all at once now, efficiently.
     // TODO: this could lazily stream functions out of the module.
     for (Module::iterator I = mod.begin(), E = mod.end(); I != E; ++I)
-      if (!I->isDeclaration())
+      if (!I->isDeclaration()) {
+        if (DisableRedZone)
+          I->addFnAttr(Attribute::NoRedZone);
         Passes.run(*I);
+      }
 
     Passes.doFinalization();
   }