From 71ac240620c4fedb6e49c302c490e99bb2d37eb4 Mon Sep 17 00:00:00 2001
From: Weiming Zhao <weimingz@codeaurora.org>
Date: Tue, 3 Feb 2015 22:35:58 +0000
Subject: [PATCH] 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 |  2 ++
 clang/lib/Sema/SemaStmtAsm.cpp                   |  6 ++++++
 clang/test/Sema/attr-naked.cpp                   | 15 +++++++++++++++
 3 files changed, 23 insertions(+)
 create mode 100644 clang/test/Sema/attr-naked.cpp

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 1283baf..9bbdab4 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/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">;
 
diff --git a/clang/lib/Sema/SemaStmtAsm.cpp b/clang/lib/Sema/SemaStmtAsm.cpp
index 0d32581..1beac36 100644
--- a/clang/lib/Sema/SemaStmtAsm.cpp
+++ b/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);
diff --git a/clang/test/Sema/attr-naked.cpp b/clang/test/Sema/attr-naked.cpp
new file mode 100644
index 0000000..eaa8e22
--- /dev/null
+++ b/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
+}
-- 
2.7.4