The getDefaultSubtargetFeatures method of SubtargetFeature did actually return a

string of features for that target. However LTO was using that string to pass
into the "create target machine" stuff. That stuff needed the feature string to
be in a particular form. In particular, it needed the CPU specified first and
then the attributes. If there isn't a CPU specified, it required it to be blank
-- e.g., ",+altivec". Yuck.

Modify the getDefaultSubtargetFeatures method to be a non-static member
function. For all attributes for a specific subtarget, it will add them in like
normal. It will also take a CPU string so that it can satisfy this horrible
syntax.

llvm-svn: 103451

llvm/include/llvm/Target/SubtargetFeature.h

@@ -108,9 +108,10 @@ public:
   // Dump feature info.
   void dump() const;
 
-  /// Retrieve a formatted string of the default features for
-  /// the specified target triple.
-  static std::string getDefaultSubtargetFeatures(const Triple &Triple);
+  /// Retrieve a formatted string of the default features for the specified
+  /// target triple.
+  void getDefaultSubtargetFeatures(const std::string &CPU,
+                                   const Triple& Triple);
 };
 
 } // End namespace llvm

llvm/lib/Target/SubtargetFeature.cpp

@@ -359,22 +359,28 @@ void SubtargetFeatures::dump() const {
   print(dbgs());
 }
 
-/// getDefaultSubtargetFeatures - Return a string listing
-/// the features associated with the target triple.
+/// getDefaultSubtargetFeatures - Return a string listing the features
+/// associated with the target triple.
 ///
 /// FIXME: This is an inelegant way of specifying the features of a
 /// subtarget. It would be better if we could encode this information
 /// into the IR. See <rdar://5972456>.
 ///
-std::string SubtargetFeatures::getDefaultSubtargetFeatures(
-                                               const Triple& Triple) {
+void SubtargetFeatures::getDefaultSubtargetFeatures(const std::string &CPU,
+                                                    const Triple& Triple) {
+  setCPU(CPU);
+
+  const char *Attrs = 0;
+
   switch (Triple.getVendor()) {
   case Triple::Apple:
     switch (Triple.getArch()) {
     case Triple::ppc:   // powerpc-apple-*
-      return std::string("altivec");
+      Attrs = "altivec";
+      break;
     case Triple::ppc64: // powerpc64-apple-*
-      return std::string("64bit,altivec");
+      Attrs = "64bit,altivec";
+      break;
     default:
       break;
     }
@@ -383,5 +389,11 @@ std::string SubtargetFeatures::getDefaultSubtargetFeatures(
     break;
   }
 
-  return std::string("");
+  StringRef SR(Attrs);
+
+  while (!SR.empty()) {
+    std::pair<StringRef, StringRef> Res = SR.split(',');
+    AddFeature(Res.first);
+    SR = Res.second;
+  }
 }

llvm/tools/lto/LTOCodeGenerator.cpp

@@ -300,8 +300,9 @@ bool LTOCodeGenerator::determineTarget(std::string& errMsg)
         }
 
         // construct LTModule, hand over ownership of module and target
-        const std::string FeatureStr =
-           SubtargetFeatures::getDefaultSubtargetFeatures(llvm::Triple(Triple));
+        SubtargetFeatures Features;
+        Features.getDefaultSubtargetFeatures("" /* cpu */, llvm::Triple(Triple));
+        std::string FeatureStr = Features.getString();
         _target = march->createTargetMachine(Triple, FeatureStr);
     }
     return false;

llvm/tools/lto/LTOModule.cpp

@@ -140,8 +140,9 @@ LTOModule* LTOModule::makeLTOModule(MemoryBuffer* buffer,
         return NULL;
 
     // construct LTModule, hand over ownership of module and target
-    const std::string FeatureStr = 
-        SubtargetFeatures::getDefaultSubtargetFeatures(llvm::Triple(Triple));
+    SubtargetFeatures Features;
+    Features.getDefaultSubtargetFeatures("" /* cpu */, llvm::Triple(Triple));
+    std::string FeatureStr = Features.getString();
     TargetMachine* target = march->createTargetMachine(Triple, FeatureStr);
     return new LTOModule(m.take(), target);
 }