Diagnose CXX 'this' pointer reference in funcs with naked attr

Clang asserts for this pointer reference in asms of naked functions.
This patch diagnoses if this pointer reference is used.

Differential Revision: http://reviews.llvm.org/D7329

llvm-svn: 228052

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -7211,6 +7211,8 @@ def err_filter_expression_integral : Error<
 
 def err_non_asm_stmt_in_naked_function : Error<
   "non-ASM statement in naked function is not supported">;
+def err_asm_naked_this_ref : Error<
+  "'this' pointer references not allowed in naked functions">;
 def err_asm_naked_parm_ref : Error<
   "parameter references not allowed in naked functions">;
 

clang/lib/Sema/SemaStmtAsm.cpp

@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Sema/SemaInternal.h"
+#include "clang/AST/ExprCXX.h"
 #include "clang/AST/RecordLayout.h"
 #include "clang/AST/TypeLoc.h"
 #include "clang/Basic/TargetInfo.h"
@@ -86,6 +87,11 @@ static bool CheckNakedParmReference(Expr *E, Sema &S) {
   WorkList.push_back(E);
   while (WorkList.size()) {
     Expr *E = WorkList.pop_back_val();
+    if (isa<CXXThisExpr>(E)) {
+      S.Diag(E->getLocStart(), diag::err_asm_naked_this_ref);
+      S.Diag(Func->getAttr<NakedAttr>()->getLocation(), diag::note_attribute);
+      return true;
+    }
     if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
       if (isa<ParmVarDecl>(DRE->getDecl())) {
         S.Diag(DRE->getLocStart(), diag::err_asm_naked_parm_ref);

clang/test/Sema/attr-naked.cpp

@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 %s -verify -fsyntax-only -triple arm-none-linux
+class Foo {
+  void bar();
+  static void bar2();
+  unsigned v;
+  static unsigned s;
+};
+
+void __attribute__((naked)) Foo::bar() { // expected-note{{attribute is here}}
+  asm("mov r2, %0" : : "r"(v)); // expected-error{{'this' pointer references not allowed in naked functions}}
+}
+
+void __attribute__((naked)) Foo::bar2() {
+  asm("mov r2, %0" : : "r"(s)); // static member reference is OK
+}