Changeset 509ec82 for src/Validate/ReplaceTypedef.cpp

Timestamp:

Dec 1, 2024, 9:04:12 PM (10 months ago)

Author:

JiadaL <j82liang@…>

Branches:

master

Children:

eae8b37

Parents:

3e2e9b2 (diff), 1c0a3a4 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge branch 'master' of plg.uwaterloo.ca:software/cfa/cfa-cc

File:

• src/Validate/ReplaceTypedef.cpp (modified) (4 diffs)

src/Validate/ReplaceTypedef.cpp

@@ -120 +120 @@
         }
 }
-
 struct VarLenChecker : public ast::WithShortCircuiting {
         bool result = false;
@@ -126 +125 @@
         void previsit( ast::ArrayType const * at ) { result |= at->isVarLen; }
 };
-
+static bool hasVarLen( const ast::Type * t ) {
+        return ast::Pass<VarLenChecker>::read( t );
+}
+struct ArrayTypeExtractor {
+        std::vector<const ast::ArrayType *> result;
+        void postvisit( const ast::ArrayType * at ) {
+                result.push_back( at );
+        }
+};
+static bool dimensionPresenceMismatched( const ast::Type * t0, const ast::Type * t1) {
+        std::vector<const ast::ArrayType *> at0s = std::move(
+                ast::Pass<ArrayTypeExtractor>::read( t0 ) );
+        std::vector<const ast::ArrayType *> at1s = std::move(
+                ast::Pass<ArrayTypeExtractor>::read( t1 ) );
+        assert( at0s.size() == at1s.size() );
+        for (size_t i = 0; i < at0s.size(); i++) {
+                const ast::ArrayType * at0 = at0s[i];
+                const ast::ArrayType * at1 = at1s[i];
+                assert( ResolvExpr::typesCompatible( at0, at1 ) );
+                if ( (at0->dimension != nullptr) != (at1->dimension != nullptr) ) return true;
+        }
+        return false;
+}
 ast::Decl const * ReplaceTypedefCore::postvisit(
                 ast::TypedefDecl const * decl ) {
@@ -133 +154 @@
                 ast::Type const * t0 = decl->base;
                 ast::Type const * t1 = typedefNames[ decl->name ].first->base;
+                // [hasVarLen]
                 // Cannot redefine VLA typedefs. Note: this is slightly incorrect,
                 // because our notion of VLAs at this point in the translator is
@@ -139 +161 @@
                 // constant/enumerator. The effort required to fix this corner case
                 // likely outweighs the utility of allowing it.
+                // [dimensionPresenceMismatched]
+                // Core typesCompatible logic interprets absent dimensions as wildcards,
+                // i.e. float[][*] matches float[][42].
+                // For detecting incompatible typedefs, we have to interpret them verbatim,
+                // i.e. float[] is different than float[42].
+                // But typesCompatible does assure that the pair of types is structurally
+                // consistent, outside of the dimension expressions.  This assurance guards
+                // the dimension-presence traversal.  So this traversal logic can (and does)
+                // assume that ArrayTypes will be encountered in analogous places.
                 if ( !ResolvExpr::typesCompatible( t0, t1 )
-                                || ast::Pass<VarLenChecker>::read( t0 )
-                                || ast::Pass<VarLenChecker>::read( t1 ) ) {
+                                || hasVarLen( t0 )
+                                || hasVarLen( t1 )
+                                || dimensionPresenceMismatched( t0, t1 ) ) {
                         SemanticError( decl->location, "Cannot redefine typedef %s", decl->name.c_str() );
                 }