[PATCH] D51426: [Sema] Prohibit function-scope compound literals with address spaces.

[Bevin Hansson via Phabricator via cfe-commits]

ebevhan created this revision.
ebevhan added reviewers: efriedma, rjmccall.
Herald added a subscriber: cfe-commits.

In C, compound literals in function scope are lvalues with
automatic storage duration. This means that generally, they
cannot be address space-qualified since you cannot have
address space-qualified objects with automatic storage duration.

We might want to check the 'alloca address space' here, but
neither ASTContext nor TargetInfo seem to have this.


Repository:
  rC Clang

https://reviews.llvm.org/D51426

Files:
  include/clang/Basic/DiagnosticSemaKinds.td
  lib/Sema/SemaExpr.cpp
  test/Sema/address_spaces.c


Index: test/Sema/address_spaces.c
===================================================================
--- test/Sema/address_spaces.c
+++ test/Sema/address_spaces.c
@@ -73,3 +73,17 @@
 char* cmp(_AS1 char *x,  _AS2 char *y) {
   return x < y ? x : y; // expected-error{{conditional operator with the second and third operands of type  ('__attribute__((address_space(1))) char *' and '__attribute__((address_space(2))) char *') which are pointers to non-overlapping address spaces}}
 }
+
+struct SomeStruct {
+  int a;
+  long b;
+  int c;
+};
+
+// Compound literals in function scope are lvalues with automatic storage duration,
+// so they cannot realistically be qualified with an address space.
+void as_compound_literal() {
+  (_AS1 struct SomeStruct){1, 2, 3}; // expected-error {{compound literal in function scope may not be qualified with an address space}}
+  (_AS1 char[]){"test"}; // expected-error {{compound literal in function scope may not be qualified with an address space}}
+  (_AS1 char[]){'a', 'b', 'c'}; // expected-error {{compound literal in function scope may not be qualified with an address space}}
+}
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -5733,12 +5733,19 @@
   LiteralExpr = Result.get();
 
   bool isFileScope = !CurContext->isFunctionOrMethod();
-  if (isFileScope &&
-      !LiteralExpr->isTypeDependent() &&
-      !LiteralExpr->isValueDependent() &&
-      !literalType->isDependentType()) { // 6.5.2.5p3
-    if (CheckForConstantInitializer(LiteralExpr, literalType))
-      return ExprError();
+  if (isFileScope) {
+    if(!LiteralExpr->isTypeDependent() &&
+       !LiteralExpr->isValueDependent() &&
+       !literalType->isDependentType()) // C99 6.5.2.5p3
+      if (CheckForConstantInitializer(LiteralExpr, literalType))
+        return ExprError();
+  } else if(literalType.getAddressSpace() != LangAS::opencl_private &&
+            literalType.getAddressSpace() != LangAS::Default) {
+    // C99 6.5.2.5p6: Function scope compound literals must have automatic
+    // storage which generally excludes address space-qualified ones.
+    Diag(LParenLoc, diag::err_compound_literal_with_address_space)
+      << SourceRange(LParenLoc, LiteralExpr->getSourceRange().getEnd());
+    return ExprError();
   }
 
   // In C, compound literals are l-values for some reason.
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -2603,6 +2603,8 @@
   "parameter may not be qualified with an address space">;
 def err_field_with_address_space : Error<
   "field may not be qualified with an address space">;
+def err_compound_literal_with_address_space : Error<
+  "compound literal in function scope may not be qualified with an address space">;
 def err_attr_objc_ownership_redundant : Error<
   "the type %0 is already explicitly ownership-qualified">;
 def err_invalid_nsnumber_type : Error<


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