Change Expr::isIntegerConstantExpr() to allow for pointer types (for GCC compatibility). Note FIXME.

Fix <rdar://problem/5977870> clang on xcode: error: arrays with static storage duration must have constant integer length


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@51907 91177308-0d34-0410-b5e6-96231b3b80d8

lib/AST/Expr.cpp

@@ -918,6 +918,11 @@ bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx,
     if (!SubExpr->getType()->isArithmeticType() ||
         !getType()->isIntegerType()) {
       if (Loc) *Loc = SubExpr->getLocStart();
+      // GCC accepts pointers as an extension.
+      // FIXME: check getLangOptions().NoExtensions. At the moment, it doesn't
+      // appear possible to get langOptions() from the Expr.
+      if (SubExpr->getType()->isPointerType()) // && !NoExtensions
+        return true;
       return false;
     }
 

test/Sema/gcc-cast-ext.m

@@ -8,6 +8,12 @@ typedef struct _NSRange { } NSRange;
 + alloc;
 - autorelease;
 @end
+
+// GCC allows pointer expressions in integer constant expressions.
+struct {
+  char control[((int)(char *)2)];
+} xx;
+
 @implementation PBXDocBookmark  // expected-warning {{incomplete implementation}} expected-warning {{method definition for 'autorelease' not found}} expected-warning {{method definition for 'alloc' not found}}
 
 + (id)bookmarkWithFileReference:(PBXFileReference *)fileRef gylphRange:(NSRange)range anchor:(NSString *)htmlAnchor