From: Michael Zuckerman <Michael.zuckerman@intel.com>
Date: Tue, 15 Dec 2015 14:04:18 +0000 (+0000)
Subject: [Microsoft][C++] Clang doesn't support a use of "this" pointer inside inline asm
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=980893d5370d3a1ab0fbf928786335b5aef95561;p=clang

[Microsoft][C++] Clang doesn't support a use of "this" pointer inside inline asm

Clang doesn’t support a use of “this” pointer inside inline asm.
When I tried to compile a class or a struct (see example) with an inline asm that contains "this" pointer.
Clang returns with an error.
This patch fixes that.

error: expected unqualified-id
For example:
'''
struct A {
    void f() {
          __asm mov eax, this
              // error: expected unqualified-id
                  }
};
'''
Differential Revision: http://reviews.llvm.org/D15115



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@255645 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index e125b805b2..cc4fa2ec59 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -1696,7 +1696,8 @@ llvm::Value* CodeGenFunction::EmitAsmInput(
   if (Info.allowsRegister() || !Info.allowsMemory())
     if (CodeGenFunction::hasScalarEvaluationKind(InputExpr->getType()))
       return EmitScalarExpr(InputExpr);
-
+  if (InputExpr->getStmtClass() == Expr::CXXThisExprClass)
+    return EmitScalarExpr(InputExpr);
   InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
   LValue Dest = EmitLValue(InputExpr);
   return EmitAsmInputLValue(Info, Dest, InputExpr->getType(), ConstraintStr,
diff --git a/lib/Parse/ParseStmtAsm.cpp b/lib/Parse/ParseStmtAsm.cpp
index d3281393f9..f469a064f8 100644
--- a/lib/Parse/ParseStmtAsm.cpp
+++ b/lib/Parse/ParseStmtAsm.cpp
@@ -215,17 +215,22 @@ ExprResult Parser::ParseMSAsmIdentifier(llvm::SmallVectorImpl<Token> &LineToks,
   // Require an identifier here.
   SourceLocation TemplateKWLoc;
   UnqualifiedId Id;
-  bool Invalid =
-      ParseUnqualifiedId(SS,
-                         /*EnteringContext=*/false,
-                         /*AllowDestructorName=*/false,
-                         /*AllowConstructorName=*/false,
-                         /*ObjectType=*/ParsedType(), TemplateKWLoc, Id);
-
-  // Perform the lookup.
-  ExprResult Result = Actions.LookupInlineAsmIdentifier(
-      SS, TemplateKWLoc, Id, Info, IsUnevaluatedContext);
-
+  bool Invalid = true;
+  ExprResult Result;
+  if (Tok.is(tok::kw_this)) {
+    Result = ParseCXXThis();
+    Invalid = false;
+  } else {
+    Invalid =
+        ParseUnqualifiedId(SS,
+                           /*EnteringContext=*/false,
+                           /*AllowDestructorName=*/false,
+                           /*AllowConstructorName=*/false,
+                           /*ObjectType=*/ParsedType(), TemplateKWLoc, Id);
+    // Perform the lookup.
+    Result = Actions.LookupInlineAsmIdentifier(SS, TemplateKWLoc, Id, Info,
+                                               IsUnevaluatedContext);
+  }
   // While the next two tokens are 'period' 'identifier', repeatedly parse it as
   // a field access. We have to avoid consuming assembler directives that look
   // like '.' 'else'.
diff --git a/test/CodeGen/ms_this.cpp b/test/CodeGen/ms_this.cpp
new file mode 100644
index 0000000000..10cd52ffc6
--- /dev/null
+++ b/test/CodeGen/ms_this.cpp
@@ -0,0 +1,49 @@
+// RUN: %clang_cc1 -fasm-blocks -emit-llvm %s -o - | FileCheck %s
+class t1 {
+public:
+  double a;
+  void runc();
+};
+
+class t2 {
+public:
+  double a;
+  void runc();
+};
+
+void t2::runc() {
+  double num = 0;
+  __asm {
+      mov rax,[this]
+      //CHECK: %this.addr = alloca %class.t2*
+      //CHECK: call void asm sideeffect inteldialect "mov rax,qword ptr $1{{.*}}%class.t2* %this1
+      mov rbx,[rax]
+      mov num, rbx
+	   };
+}
+
+void t1::runc() {
+  double num = 0;
+  __asm {
+       mov rax,[this]
+      //CHECK: %this.addr = alloca %class.t1*
+      //CHECK: call void asm sideeffect inteldialect "mov rax,qword ptr $1{{.*}}%class.t1* %this1
+        mov rbx,[rax]
+        mov num, rbx
+	   };
+}
+
+struct s {
+  int a;
+  void func() {
+    __asm mov rax, [this]
+    //CHECK: %this.addr = alloca %struct.s*
+    //CHECK: call void asm sideeffect inteldialect "mov rax, qword ptr $0{{.*}}%struct.s* %this1
+  }
+} f3;
+
+int main() {
+  f3.func();
+  f3.a=1;
+  return 0;
+}