[PATCH] D15691: [OpenCL] Improving OpenCL function pointer error checking to catch lone function designator

[Neil Hickey via cfe-commits]

neil.hickey created this revision.
neil.hickey added a reviewer: cfe-commits.

An undecorated function designator implies taking the address of a function, which is illegal in OpenCL. Implementing a check for this earlier to allow the error to be reported even in the presence of other more obvious errors.

http://reviews.llvm.org/D15691

Files:
  include/clang/Basic/DiagnosticParseKinds.td
  lib/Parse/ParseExpr.cpp
  test/SemaOpenCL/cond.cl
  test/SemaOpenCL/func_ptr.cl

Index: test/SemaOpenCL/func_ptr.cl
===================================================================
--- test/SemaOpenCL/func_ptr.cl
+++ test/SemaOpenCL/func_ptr.cl
@@ -11,6 +11,9 @@
   foo((void*)foo); // expected-error{{taking address of function is not allowed}}
   foo(&foo); // expected-error{{taking address of function is not allowed}}
 
+  // initializing an array with the address of functions is an error
+  void* vptrarr[2] = {foo, &foo}; // expected-error{{taking address of function is not allowed}} expected-error{{taking address of function is not allowed}}
+
   // just calling a function is correct
   foo(0);
 }
Index: test/SemaOpenCL/cond.cl
===================================================================
--- test/SemaOpenCL/cond.cl
+++ test/SemaOpenCL/cond.cl
@@ -128,5 +128,5 @@
 
 unsigned int ntest12(int2 C)
 {
-  return (unsigned int)(C ? foo1 : foo2); // expected-error {{taking address of function is not allowed}}
+  return (unsigned int)(C ? foo1 : foo2); // expected-error {{taking address of function is not allowed}} expected-error {{taking address of function is not allowed}}
 }
Index: lib/Parse/ParseExpr.cpp
===================================================================
--- lib/Parse/ParseExpr.cpp
+++ lib/Parse/ParseExpr.cpp
@@ -1334,8 +1334,23 @@
     return ExprError();
   }
 
+  // check to see whether Res is a function designator only. If it is and we
+  // are compiling for OpenCL, we need to return an error as this implies
+  // that the address of the function is being taken, which is illegal in CL
+
   // These can be followed by postfix-expr pieces.
-  return ParsePostfixExpressionSuffix(Res);
+  Res = ParsePostfixExpressionSuffix(Res);
+  Expr *PostfixExpr = Res.get();
+  if (PostfixExpr) {
+    QualType Ty = PostfixExpr->getType();
+    if (!Ty.isNull() && Ty->isFunctionType() && getLangOpts().OpenCL) {
+      Diag(PostfixExpr->getExprLoc(),
+           diag::err_opencl_taking_function_address_parser);
+      return ExprError();
+    }
+  }
+
+  return Res;
 }
 
 /// \brief Once the leading part of a postfix-expression is parsed, this
Index: include/clang/Basic/DiagnosticParseKinds.td
===================================================================
--- include/clang/Basic/DiagnosticParseKinds.td
+++ include/clang/Basic/DiagnosticParseKinds.td
@@ -910,6 +910,10 @@
 def warn_pragma_unknown_extension : Warning<
   "unknown OpenCL extension %0 - ignoring">, InGroup<IgnoredPragmas>;
 
+// OpenCL error
+def err_opencl_taking_function_address_parser : Error<
+  "taking address of function is not allowed">;
+
 // OpenMP support.
 def warn_pragma_omp_ignored : Warning<
   "unexpected '#pragma omp ...' in program">, InGroup<SourceUsesOpenMP>, DefaultIgnore;


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