Change createAsmParser to take a MCSubtargetInfo instead of triple,

CPU, and feature string. Parsing some asm directives can change
subtarget state (e.g. .code 16) and it must be reflected in other
modules (e.g. MCCodeEmitter). That is, the MCSubtargetInfo instance
must be shared.

llvm-svn: 134795

1 files changed, 32 insertions, 0 deletions

diff --git a/llvm/lib/MC/SubtargetFeature.cpp b/llvm/lib/MC/SubtargetFeature.cpp
index 951e0aa..348cd4c 100644
--- a/llvm/lib/MC/SubtargetFeature.cpp
+++ b/llvm/lib/MC/SubtargetFeature.cpp
@@ -224,6 +224,38 @@ void ClearImpliedBits(uint64_t &Bits, const SubtargetFeatureKV *FeatureEntry,
   }
 }
 
+/// ToggleFeature - Toggle a feature and returns the newly updated feature
+/// bits.
+uint64_t
+SubtargetFeatures::ToggleFeature(uint64_t Bits, const StringRef Feature,
+                                 const SubtargetFeatureKV *FeatureTable,
+                                 size_t FeatureTableSize) {
+  // Find feature in table.
+  const SubtargetFeatureKV *FeatureEntry =
+    Find(StripFlag(Feature), FeatureTable, FeatureTableSize);
+  // If there is a match
+  if (FeatureEntry) {
+    if ((Bits & FeatureEntry->Value) == FeatureEntry->Value) {
+      Bits &= ~FeatureEntry->Value;
+
+      // For each feature that implies this, clear it.
+      ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
+    } else {
+      Bits |=  FeatureEntry->Value;
+
+      // For each feature that this implies, set it.
+      SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
+    }
+  } else {
+    errs() << "'" << Feature
+           << "' is not a recognized feature for this target"
+           << " (ignoring feature)\n";
+  }
+
+  return Bits;
+}
+           
+
 /// getFeatureBits - Get feature bits a CPU.
 ///
 uint64_t SubtargetFeatures::getFeatureBits(const StringRef CPU,