Fix evil TableGen bug in template parameters with defaults.

If a TableGen class has an initializer expression containing an X.Y subexpression,
AND X depends on template parameters,
AND those template parameters have defaults,
AND some parameters with defaults are beyond position 1,
THEN parts of the initializer expression are evaluated prematurely with the default values when the first explicit template parameter is substituted, before the remaining explicit template parameters have been substituted.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99492 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/TableGen/2010-03-24-PrematureDefaults.td b/test/TableGen/2010-03-24-PrematureDefaults.td
new file mode 100644 (file)
index 0000000..42f2632
--- /dev/null
+++ b/test/TableGen/2010-03-24-PrematureDefaults.td
@@ -0,0 +1,43 @@
+// RUN: tblgen %s | FileCheck %s
+
+class A<int k, bits<2> x = 1> {
+  int K = k;
+  bits<2> Bits = x;
+}
+
+// CHECK: def a1
+// CHECK: Bits = { 0, 1 }
+def a1 : A<12>;
+
+// CHECK: def a2
+// CHECK: Bits = { 1, 0 }
+def a2 : A<13, 2>;
+
+// Here was the bug: X.Bits would get resolved to the default a1.Bits while
+// resolving the first template argument. When the second template argument
+// was processed, X would be set correctly, but Bits retained the default
+// value.
+class B<int k, A x = a1> {
+  A X = x;
+  bits<2> Bits = X.Bits;
+}
+
+// CHECK: def b1
+// CHECK: Bits = { 0, 1 }
+def b1 : B<27>;
+
+// CHECK: def b2
+// CHECK: Bits = { 1, 0 }
+def b2 : B<28, a2>;
+
+class C<A x = a1> {
+  bits<2> Bits = x.Bits;
+}
+
+// CHECK: def c1
+// CHECK: Bits = { 0, 1 }
+def c1 : C;
+
+// CHECK: def c2
+// CHECK: Bits = { 1, 0 }
+def c2 : C<a2>;

diff --git a/utils/TableGen/Record.cpp b/utils/TableGen/Record.cpp
index b9facb4c2a6e21f1f63618e6dc1e8cbde36392a6..0e3593b6a11ff2cc1eb8e864176bc75a625bab7b 100644 (file)
--- a/utils/TableGen/Record.cpp
+++ b/utils/TableGen/Record.cpp
@@ -1108,12 +1108,15 @@ RecTy *VarInit::getFieldType(const std::string &FieldName) const {
   return 0;
 }
 
-Init *VarInit::getFieldInit(Record &R, const std::string &FieldName) const {
+Init *VarInit::getFieldInit(Record &R, const RecordVal *RV,
+                            const std::string &FieldName) const {
   if (dynamic_cast<RecordRecTy*>(getType()))
-    if (const RecordVal *RV = R.getValue(VarName)) {
-      Init *TheInit = RV->getValue();
+    if (const RecordVal *Val = R.getValue(VarName)) {
+      if (RV != Val && (RV || dynamic_cast<UnsetInit*>(Val->getValue())))
+        return 0;
+      Init *TheInit = Val->getValue();
       assert(TheInit != this && "Infinite loop detected!");
-      if (Init *I = TheInit->getFieldInit(R, FieldName))
+      if (Init *I = TheInit->getFieldInit(R, RV, FieldName))
         return I;
       else
         return 0;
@@ -1174,7 +1177,8 @@ RecTy *DefInit::getFieldType(const std::string &FieldName) const {
   return 0;
 }
 
-Init *DefInit::getFieldInit(Record &R, const std::string &FieldName) const {
+Init *DefInit::getFieldInit(Record &R, const RecordVal *RV,
+                            const std::string &FieldName) const {
   return Def->getValue(FieldName)->getValue();
 }
 
@@ -1185,7 +1189,7 @@ std::string DefInit::getAsString() const {
 
 Init *FieldInit::resolveBitReference(Record &R, const RecordVal *RV,
                                      unsigned Bit) {
-  if (Init *BitsVal = Rec->getFieldInit(R, FieldName))
+  if (Init *BitsVal = Rec->getFieldInit(R, RV, FieldName))
     if (BitsInit *BI = dynamic_cast<BitsInit*>(BitsVal)) {
       assert(Bit < BI->getNumBits() && "Bit reference out of range!");
       Init *B = BI->getBit(Bit);
@@ -1198,7 +1202,7 @@ Init *FieldInit::resolveBitReference(Record &R, const RecordVal *RV,
 
 Init *FieldInit::resolveListElementReference(Record &R, const RecordVal *RV,
                                              unsigned Elt) {
-  if (Init *ListVal = Rec->getFieldInit(R, FieldName))
+  if (Init *ListVal = Rec->getFieldInit(R, RV, FieldName))
     if (ListInit *LI = dynamic_cast<ListInit*>(ListVal)) {
       if (Elt >= LI->getSize()) return 0;
       Init *E = LI->getElement(Elt);
@@ -1215,7 +1219,7 @@ Init *FieldInit::resolveListElementReference(Record &R, const RecordVal *RV,
 Init *FieldInit::resolveReferences(Record &R, const RecordVal *RV) {
   Init *NewRec = RV ? Rec->resolveReferences(R, RV) : Rec;
 
-  Init *BitsVal = NewRec->getFieldInit(R, FieldName);
+  Init *BitsVal = NewRec->getFieldInit(R, RV, FieldName);
   if (BitsVal) {
     Init *BVR = BitsVal->resolveReferences(R, RV);
     return BVR->isComplete() ? BVR : this;

diff --git a/utils/TableGen/Record.h b/utils/TableGen/Record.h
index 90096e98e206003f8fd3314cab627b03a834c574..55c1a80f9b6a048d3297f6044d3235b9191e0f7c 100644 (file)
--- a/utils/TableGen/Record.h
+++ b/utils/TableGen/Record.h
@@ -503,7 +503,8 @@ struct Init {
   /// initializer for the specified field.  If getFieldType returns non-null
   /// this method should return non-null, otherwise it returns null.
   ///
-  virtual Init *getFieldInit(Record &R, const std::string &FieldName) const {
+  virtual Init *getFieldInit(Record &R, const RecordVal *RV,
+                             const std::string &FieldName) const {
     return 0;
   }
 
@@ -950,7 +951,8 @@ public:
                                             unsigned Elt);
 
   virtual RecTy *getFieldType(const std::string &FieldName) const;
-  virtual Init *getFieldInit(Record &R, const std::string &FieldName) const;
+  virtual Init *getFieldInit(Record &R, const RecordVal *RV,
+                             const std::string &FieldName) const;
 
   /// resolveReferences - This method is used by classes that refer to other
   /// variables which may not be defined at the time they expression is formed.
@@ -1035,7 +1037,8 @@ public:
   //virtual Init *convertInitializerBitRange(const std::vector<unsigned> &Bits);
 
   virtual RecTy *getFieldType(const std::string &FieldName) const;
-  virtual Init *getFieldInit(Record &R, const std::string &FieldName) const;
+  virtual Init *getFieldInit(Record &R, const RecordVal *RV,
+                             const std::string &FieldName) const;
 
   virtual std::string getAsString() const;