Changeset 4b97770 for src

Timestamp:

Jan 3, 2018, 10:40:02 AM (6 years ago)

Author:

Rob Schluntz <rschlunt@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, resolv-new, with_gc

Children:

6138d0f, b834e98

Parents:

be9aa0f

Message:

Add error handling for C-style initialization of VLAs

Location:

src

Files:

• ResolvExpr/CurrentObject.cc (modified) (7 diffs)
• SymTab/Validate.cc (modified) (1 diff)

src/ResolvExpr/CurrentObject.cc

@@ -125 +125 @@
                         base = at->get_base();
                         memberIter = createMemberIterator( base );
+                        if ( at->isVarLen ) throw SemanticError( "VLA initialization does not support @=", at );
                         setSize( at->get_dimension() );
                 }
@@ -135 +136 @@
                 void setSize( Expression * expr ) {
                         if ( ConstantExpr * constExpr = dynamic_cast< ConstantExpr * >( expr ) ) {
-                                size = constExpr->intValue();
-                                isVLA = false;
-                                PRINT( std::cerr << "array type with size: " << size << std::endl; )
+                                try {
+                                        size = constExpr->intValue();
+                                        PRINT( std::cerr << "array type with size: " << size << std::endl; )
+                                } catch ( SemanticError & ) {
+                                        throw SemanticError( "Constant expression of non-integral type in array dimension: ", expr );
+                                }
                         }       else if ( CastExpr * castExpr = dynamic_cast< CastExpr * >( expr ) ) {
                                 setSize( castExpr->get_arg() ); // xxx - need to perform the conversion specified by the cast
@@ -145 +149 @@
                                         if ( inst->baseEnum->valueOf( varExpr->var, value ) ) {
                                                 size = value;
-                                                isVLA = false;
                                         }
                                 }
@@ -157 +160 @@
                         // need to permit integer-constant-expressions, including: integer constants, enumeration constants, character constants, sizeof expressions, _Alignof expressions, cast expressions
                         if ( ConstantExpr * constExpr = dynamic_cast< ConstantExpr * >( expr ) ) {
-                                index = constExpr->intValue();
+                                try {
+                                        index = constExpr->intValue();
+                                } catch( SemanticError & ) {
+                                        throw SemanticError( "Constant expression of non-integral type in array designator: ", expr );
+                                }
                         } else if ( CastExpr * castExpr = dynamic_cast< CastExpr * >( expr ) ) {
                                 setPosition( castExpr->get_arg() );
@@ -186 +193 @@
                 }
 
-                virtual operator bool() const { return ! isVLA && index < size; }
+                virtual operator bool() const { return index < size; }
 
                 virtual MemberIterator & bigStep() {
@@ -192 +199 @@
                         ++index;
                         delete memberIter;
-                        if ( ! isVLA && index < size ) memberIter = createMemberIterator( base );
+                        if ( index < size ) memberIter = createMemberIterator( base );
                         else memberIter = nullptr;
                         return *this;
@@ -239 +246 @@
                 size_t index = 0;
                 size_t size = 0;
-                bool isVLA = true;
                 MemberIterator * memberIter = nullptr;
         };

src/SymTab/Validate.cc

@@ -754 +754 @@
                                 throw SemanticError( "Cannot redefine typedef: " + tyDecl->name );
                         }
-                        // cannot redefine VLA typedefs
+                        // Cannot redefine VLA typedefs. Note: this is slightly incorrect, because our notion of VLAs
+                        // at this point in the translator is imprecise. In particular, this will disallow redefining typedefs
+                        // with arrays whose dimension is an enumerator or a cast of a constant/enumerator. The effort required
+                        // to fix this corner case likely outweighs the utility of allowing it.
                         if ( isVariableLength( t1 ) || isVariableLength( t2 ) ) {
                                 throw SemanticError( "Cannot redefine typedef: " + tyDecl->name );