Support arithmetic on pointer-to-function types as a GNU

extension. Addresses clang PR/3371.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@62823 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticKinds.def b/include/clang/Basic/DiagnosticKinds.def
index 259265c2bfc83313396313f54b6b04f7d5e44a22..1858f2583bec6da96352031319ff9c4a97ce881e 100644 (file)
--- a/include/clang/Basic/DiagnosticKinds.def
+++ b/include/clang/Basic/DiagnosticKinds.def
@@ -345,7 +345,9 @@ DIAG(ext_gnu_old_style_field_designator, EXTENSION,
      "use of GNU old-style field designator extension")
 DIAG(ext_gnu_case_range, EXTENSION,
      "use of GNU case range extension")
-   
+DIAG(ext_gnu_ptr_func_arith, EXTENSION,
+     "arithmetic on pointer to function type %0 is a GNU extension")
+
 // Generic errors.
 DIAG(err_parse_error, ERROR,
      "parse error")
@@ -1262,6 +1264,8 @@ DIAG(err_typecheck_arithmetic_incomplete_type, ERROR,
      "arithmetic on pointer to incomplete type %0")
 DIAG(err_typecheck_pointer_arith_function_type, ERROR,
      "arithmetic on pointer to function type %0")
+DIAG(err_typecheck_pointer_arith_void_type, ERROR,
+     "arithmetic on pointer to void type")
 DIAG(err_typecheck_decl_incomplete_type, ERROR,
      "variable has incomplete type %0")
 // FIXME: Use %select

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 8cf153e673dd8be7f2c48d4a45aad15434ab2ba7..ab5bd6bd11942fa3142845d77e5f9ee3d40aa17a 100644 (file)
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -2656,12 +2656,25 @@ inline QualType Sema::CheckAdditionOperands( // C99 6.5.6
       // Check for arithmetic on pointers to incomplete types
       if (!PTy->getPointeeType()->isObjectType()) {
         if (PTy->getPointeeType()->isVoidType()) {
+          if (getLangOptions().CPlusPlus) {
+            Diag(Loc, diag::err_typecheck_pointer_arith_void_type)
+              << lex->getSourceRange() << rex->getSourceRange();
+            return QualType();
+          }
+
+          // GNU extension: arithmetic on pointer to void
           Diag(Loc, diag::ext_gnu_void_ptr)
             << lex->getSourceRange() << rex->getSourceRange();
         } else if (PTy->getPointeeType()->isFunctionType()) {
-          Diag(Loc, diag::err_typecheck_pointer_arith_function_type)
+          if (getLangOptions().CPlusPlus) {
+            Diag(Loc, diag::err_typecheck_pointer_arith_function_type)
+              << lex->getType() << lex->getSourceRange();
+            return QualType();
+          }
+
+          // GNU extension: arithmetic on pointer to function
+          Diag(Loc, diag::ext_gnu_ptr_func_arith)
             << lex->getType() << lex->getSourceRange();
-          return QualType();
         } else {
           DiagnoseIncompleteType(Loc, PTy->getPointeeType(), 
                                  diag::err_typecheck_arithmetic_incomplete_type,
@@ -2701,6 +2714,16 @@ QualType Sema::CheckSubtractionOperands(Expr *&lex, Expr *&rex,
       if (lpointee->isVoidType()) {
         Diag(Loc, diag::ext_gnu_void_ptr)
           << lex->getSourceRange() << rex->getSourceRange();
+      } else if (lpointee->isFunctionType()) {
+        if (getLangOptions().CPlusPlus) {
+          Diag(Loc, diag::err_typecheck_pointer_arith_function_type)
+            << lex->getType() << lex->getSourceRange();
+          return QualType();
+        }
+
+        // GNU extension: arithmetic on pointer to function
+        Diag(Loc, diag::ext_gnu_ptr_func_arith)
+          << lex->getType() << lex->getSourceRange();
       } else {
         Diag(Loc, diag::err_typecheck_sub_ptr_object)
           << lex->getType() << lex->getSourceRange();
@@ -3174,10 +3197,22 @@ QualType Sema::CheckIncrementDecrementOperand(Expr *Op, SourceLocation OpLoc,
     if (PT->getPointeeType()->isObjectType()) {
       // Pointer to object is ok!
     } else if (PT->getPointeeType()->isVoidType()) {
-      // Pointer to void is extension.
+      if (getLangOptions().CPlusPlus) {
+        Diag(OpLoc, diag::err_typecheck_pointer_arith_void_type)
+          << Op->getSourceRange();
+        return QualType();
+      }
+
+      // Pointer to void is a GNU extension in C.
       Diag(OpLoc, diag::ext_gnu_void_ptr) << Op->getSourceRange();
     } else if (PT->getPointeeType()->isFunctionType()) {
-      Diag(OpLoc, diag::err_typecheck_pointer_arith_function_type)
+      if (getLangOptions().CPlusPlus) {
+        Diag(OpLoc, diag::err_typecheck_pointer_arith_function_type)
+          << Op->getType() << Op->getSourceRange();
+        return QualType();
+      }
+
+      Diag(OpLoc, diag::ext_gnu_ptr_func_arith)
         << ResType << Op->getSourceRange();
       return QualType();
     } else {

diff --git a/test/Sema/pointer-addition.c b/test/Sema/pointer-addition.c
index 95f364fc676bb9854c2e8c18b277b55c30d34608..81a1dc06c1f2651f08505c69eb06c59343fdad62 100644 (file)
--- a/test/Sema/pointer-addition.c
+++ b/test/Sema/pointer-addition.c
@@ -2,13 +2,18 @@
 
 typedef struct S S; // expected-note{{forward declaration of 'struct S'}}
 void a(S* b, void* c) {
+  void (*fp)(int) = 0;
   b++;       // expected-error {{arithmetic on pointer to incomplete type}}
   b += 1;    // expected-error {{arithmetic on pointer to incomplete type}}
   c++;       // expected-warning {{use of GNU void* extension}}
   c += 1;    // expected-warning {{use of GNU void* extension}}
+  c--;       // expected-warning {{use of GNU void* extension}}
+  c -= 1;    // expected-warning {{use of GNU void* extension}}
   b = 1+b;   // expected-error {{arithmetic on pointer to incomplete type}}
   /* The next couple tests are only pedantic warnings in gcc */
   void (*d)(S*,void*) = a;
-  d += 1;    // expected-error {{arithmetic on pointer to function type}}}
-  d++;       // expected-error {{arithmetic on pointer to function type}}}
+  d += 1;    // expected-warning {{arithmetic on pointer to function type 'void (*)(S *, void *)' is a GNU extension}}
+  d++;       // expected-warning {{arithmetic on pointer to function type 'void (*)(S *, void *)' is a GNU extension}}}
+  d--;       // expected-warning {{arithmetic on pointer to function type 'void (*)(S *, void *)' is a GNU extension}}
+  d -= 1;    // expected-warning {{arithmetic on pointer to function type 'void (*)(S *, void *)' is a GNU extension}}
 }