implement support for propagating *features* down to the code generator

and defining target-specific macros based on them (like __SSE3__ and 
friends).  After extensive discussion with Daniel, this work will need
driver support, which will translate things like -msse3 into a -mattr 
feature.  Until this work is done, the code in clang.cpp is disabled and
the X86TargetInfo ctor still defaults to SSE2.  With these two things
changed, this code will work.  PR3634

llvm-svn: 65966

1 files changed, 41 insertions, 8 deletions

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index bb9c861a170..04ab3afdb14 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -420,7 +420,10 @@ class X86TargetInfo : public TargetInfo {
   } SSELevel;
 public:
   X86TargetInfo(const std::string& triple) 
-    : TargetInfo(triple), SSELevel(SSE2) {
+    : TargetInfo(triple),
+      // FIXME: hard coding to SSE2 for now.  This should change to NoMMXSSE so
+      // that the driver controls this.
+      SSELevel(SSE2) {
     LongDoubleFormat = &llvm::APFloat::x87DoubleExtended;
   }
   virtual void getTargetBuiltins(const Builtin::Info *&Records,
@@ -449,19 +452,49 @@ public:
   }
   virtual void getTargetDefines(std::vector<char> &Defines) const;
   
-  virtual int HandleTargetOptions(std::string *StrArray, unsigned NumStrs,
-                                  std::string &ErrorReason);
+  virtual int HandleTargetFeatures(std::string *StrArray, unsigned NumStrs,
+                                   std::string &ErrorReason);
 };
 
 /// HandleTargetOptions - Handle target-specific options like -msse2 and
 /// friends.  An array of arguments is passed in: if they are all valid, this
 /// should handle them and return -1.  If there is an error, the index of the
 /// invalid argument should be returned along with an optional error string.
-int X86TargetInfo::HandleTargetOptions(std::string *StrArray, unsigned NumStrs,
-                                       std::string &ErrorReason) {
-  if (NumStrs == 0)
-    return -1;
-  return 0;
+int X86TargetInfo::HandleTargetFeatures(std::string *StrArray, unsigned NumStrs,
+                                        std::string &ErrorReason) {
+  for (unsigned i = 0; i != NumStrs; ++i) {
+    const std::string &Feature = StrArray[i];
+    if (Feature.size() < 2) return i;
+    // Ignore explicitly disabled features.
+    if (Feature[0] == '-') continue;
+    
+    // Feature strings are of the form "+feature".
+    if (Feature[0] != '+') return i;
+    
+    // The set of supported subtarget features is defined in
+    // lib/Target/X86/X86.td.  Here we recognize and map onto our internal
+    // state.
+    if (Feature == "+mmx")
+      SSELevel = std::max(SSELevel, MMX);
+    else if (Feature == "+sse")
+      SSELevel = std::max(SSELevel, SSE1);
+    else if (Feature == "+sse2")
+      SSELevel = std::max(SSELevel, SSE2);
+    else if (Feature == "+sse3")
+      SSELevel = std::max(SSELevel, SSE3);
+    else if (Feature == "+ssse3")
+      SSELevel = std::max(SSELevel, SSSE3);
+    else if (Feature == "+sse41")
+      SSELevel = std::max(SSELevel, SSE41);
+    else if (Feature == "+sse42")
+      SSELevel = std::max(SSELevel, SSE42);
+    else if (Feature == "+64bit" || Feature == "+slow-bt-mem")
+      // Ignore these features.
+      continue;
+    else
+      return i;
+  }
+  return -1;
 }
 
 /// X86TargetInfo::getTargetDefines - Return a set of the X86-specific #defines