From: Reid Kleckner <reid@kleckner.net>
Date: Wed, 26 Mar 2014 15:38:33 +0000 (+0000)
Subject: -fms-extensions: Add __va_start builtin, which is used for x64
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e1972b5edc56db7fe344a7a5da33025db4646563;p=clang

-fms-extensions: Add __va_start builtin, which is used for x64

The main difference between __va_start and __builtin_va_start is that
the address of the va_list has already been taken, and the va_list is
always a char*.

__va_end and __va_arg are not needed.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@204821 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Basic/Builtins.def b/include/clang/Basic/Builtins.def
index 53bec2ab83..540ec25bad 100644
--- a/include/clang/Basic/Builtins.def
+++ b/include/clang/Basic/Builtins.def
@@ -681,6 +681,7 @@ LANGBUILTIN(_alloca,      "v*z", "n", ALL_MS_LANGUAGES)
 LANGBUILTIN(__assume,     "vb",  "n", ALL_MS_LANGUAGES)
 LANGBUILTIN(__noop,       "v.",  "n", ALL_MS_LANGUAGES)
 LANGBUILTIN(__debugbreak, "v",   "n", ALL_MS_LANGUAGES)
+LANGBUILTIN(__va_start,   "vc**.", "nt", ALL_MS_LANGUAGES)
 LANGBUILTIN(_InterlockedCompareExchange, "LiLiD*LiLi", "n", ALL_MS_LANGUAGES)
 LANGBUILTIN(_InterlockedIncrement, "LiLiD*", "n", ALL_MS_LANGUAGES)
 LANGBUILTIN(_InterlockedDecrement, "LiLiD*", "n", ALL_MS_LANGUAGES)
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index c105d80bf7..b0e63b647d 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -215,8 +215,11 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
     return RValue::get(CGM.EmitConstantExpr(E, E->getType(), 0));
   case Builtin::BI__builtin_stdarg_start:
   case Builtin::BI__builtin_va_start:
+  case Builtin::BI__va_start:
   case Builtin::BI__builtin_va_end: {
-    Value *ArgValue = EmitVAListRef(E->getArg(0));
+    Value *ArgValue = (BuiltinID == Builtin::BI__va_start)
+                          ? EmitScalarExpr(E->getArg(0))
+                          : EmitVAListRef(E->getArg(0));
     llvm::Type *DestType = Int8PtrTy;
     if (ArgValue->getType() != DestType)
       ArgValue = Builder.CreateBitCast(ArgValue, DestType,
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 0285231305..f0e93a78f7 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -142,6 +142,7 @@ Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
     break;
   case Builtin::BI__builtin_stdarg_start:
   case Builtin::BI__builtin_va_start:
+  case Builtin::BI__va_start:
     if (SemaBuiltinVAStart(TheCall))
       return ExprError();
     break;
diff --git a/test/Sema/MicrosoftExtensions.c b/test/Sema/MicrosoftExtensions.c
index 4441f17973..a4afcb1e64 100644
--- a/test/Sema/MicrosoftExtensions.c
+++ b/test/Sema/MicrosoftExtensions.c
@@ -131,3 +131,17 @@ int *(__ptr32 __sptr wrong9); // expected-error {{'__sptr' attribute only applie
 
 typedef int *T;
 T __ptr32 wrong10; // expected-error {{'__ptr32' attribute only applies to pointer arguments}}
+
+typedef char *my_va_list;
+void __cdecl __va_start(my_va_list *ap, ...); // expected-note {{passing argument to parameter 'ap' here}}
+void vmyprintf(const char *f, my_va_list ap);
+void myprintf(const char *f, ...) {
+  my_va_list ap;
+  if (1) {
+    __va_start(&ap, f);
+    vmyprintf(f, ap);
+    ap = 0;
+  } else {
+    __va_start(ap, f); // expected-warning {{incompatible pointer types passing 'my_va_list'}}
+  }
+}