[llvm-commits] CVS: llvm/lib/Target/SubtargetFeature.cpp Target.td

[Bill Wendling]

Changes in directory llvm/lib/Target:

SubtargetFeature.cpp updated: 1.12 -> 1.13
Target.td updated: 1.98 -> 1.99
---
Log message:

Add an "implies" field to features. This indicates that, if the current
feature is set, then the features in the implied list should be set also.
The opposite is also enforced: if a feature in the implied list isn't set,
then the feature that owns that implies list shouldn't be set either.


---
Diffs of the changes:  (+56 -3)

 SubtargetFeature.cpp |   51 +++++++++++++++++++++++++++++++++++++++++++++++++--
 Target.td            |    8 +++++++-
 2 files changed, 56 insertions(+), 3 deletions(-)


Index: llvm/lib/Target/SubtargetFeature.cpp
diff -u llvm/lib/Target/SubtargetFeature.cpp:1.12 llvm/lib/Target/SubtargetFeature.cpp:1.13
--- llvm/lib/Target/SubtargetFeature.cpp:1.12	Thu Dec  7 17:41:45 2006
+++ llvm/lib/Target/SubtargetFeature.cpp	Fri May  4 15:38:40 2007
@@ -199,6 +199,43 @@
   if (Features[0].empty()) setCPU(String);
 }
 
+/// SetImpliedBits - For each feature that is (transitively) implied by this
+/// feature, set it.
+/// 
+static
+void SetImpliedBits(uint32_t &Bits, const SubtargetFeatureKV *FeatureEntry,
+                    const SubtargetFeatureKV *FeatureTable,
+                    size_t FeatureTableSize) {
+  for (size_t i = 0; i < FeatureTableSize; ++i) {
+    const SubtargetFeatureKV &FE = FeatureTable[i];
+
+    if (FeatureEntry->Value == FE.Value) continue;
+
+    if (FeatureEntry->Implies & FE.Value) {
+      Bits |= FE.Value;
+      SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
+    }
+  }
+}
+
+/// ClearImpliedBits - For each feature that (transitively) implies this
+/// feature, clear it.
+/// 
+static
+void ClearImpliedBits(uint32_t &Bits, const SubtargetFeatureKV *FeatureEntry,
+                      const SubtargetFeatureKV *FeatureTable,
+                      size_t FeatureTableSize) {
+  for (size_t i = 0; i < FeatureTableSize; ++i) {
+    const SubtargetFeatureKV &FE = FeatureTable[i];
+
+    if (FeatureEntry->Value == FE.Value) continue;
+
+    if (FE.Implies & FeatureEntry->Value) {
+      Bits &= ~FE.Value;
+      ClearImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
+    }
+  }
+}
 
 /// getBits - Get feature bits.
 ///
@@ -251,8 +288,17 @@
     // If there is a match
     if (FeatureEntry) {
       // Enable/disable feature in bits
-      if (isEnabled(Feature)) Bits |=  FeatureEntry->Value;
-      else                    Bits &= ~FeatureEntry->Value;
+      if (isEnabled(Feature)) {
+        Bits |=  FeatureEntry->Value;
+
+        // For each feature that this implies, set it.
+        SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
+      } else {
+        Bits &= ~FeatureEntry->Value;
+
+        // For each feature that implies this, clear it.
+        ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
+      }
     } else {
       cerr << "'" << Feature
            << "' is not a recognized feature for this target"
@@ -260,6 +306,7 @@
            << "\n";
     }
   }
+
   return Bits;
 }
 


Index: llvm/lib/Target/Target.td
diff -u llvm/lib/Target/Target.td:1.98 llvm/lib/Target/Target.td:1.99
--- llvm/lib/Target/Target.td:1.98	Wed May  2 19:27:11 2007
+++ llvm/lib/Target/Target.td	Fri May  4 15:38:40 2007
@@ -338,7 +338,8 @@
 //===----------------------------------------------------------------------===//
 // SubtargetFeature - A characteristic of the chip set.
 //
-class SubtargetFeature<string n, string a,  string v, string d> {
+class SubtargetFeature<string n, string a,  string v, string d,
+                       list<SubtargetFeature> i = []> {
   // Name - Feature name.  Used by command line (-mattr=) to determine the
   // appropriate target chip.
   //
@@ -356,6 +357,11 @@
   // information.
   //
   string Desc = d;
+
+  // Implies - Features that this feature implies are present. If one of those
+  // features isn't set, then this one shouldn't be set either.
+  //
+  list<SubtargetFeature> Implies = i;
 }
 
 //===----------------------------------------------------------------------===//