[ms-cxxabi] Destroy temporary record arguments in the callee

Itanium destroys them in the caller at the end of the full expression,
but MSVC destroys them in the callee.  This is further complicated by
the need to emit EH-only destructor cleanups in the caller.

This should help clang compile MSVC's debug iterators more correctly.
There is still an outstanding issue in PR5064 of a memcpy emitted by the
LLVM backend, which is not correct for C++ records.

Fixes PR16226.

Reviewers: rjmccall

Differential Revision: http://llvm-reviews.chandlerc.com/D929

llvm-svn: 184543

1 files changed, 118 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/microsoft-abi-exceptions.cpp b/clang/test/CodeGenCXX/microsoft-abi-exceptions.cpp
new file mode 100644
index 00000000000..383270a1f2e
--- /dev/null
+++ b/clang/test/CodeGenCXX/microsoft-abi-exceptions.cpp
@@ -0,0 +1,118 @@
+// RUN: %clang_cc1 -emit-llvm %s -o - -triple=i386-pc-win32 -cxx-abi microsoft -fexceptions | FileCheck -check-prefix WIN32 %s
+
+struct A {
+  A();
+  ~A();
+  int a;
+};
+
+A getA();
+
+int TakesTwo(A a, A b);
+void HasEHCleanup() {
+  TakesTwo(getA(), getA());
+}
+
+// With exceptions, we need to clean up at least one of these temporaries.
+// WIN32: define void @"\01?HasEHCleanup@@YAXXZ"() {{.*}} {
+//    First one doesn't have any cleanups, no need for invoke.
+// WIN32:   call void @"\01?getA@@YA?AUA@@XZ"(%struct.A* sret %{{.*}})
+//    If this call throws, we have to cleanup the first temporary.
+// WIN32:   invoke void @"\01?getA@@YA?AUA@@XZ"(%struct.A* sret %{{.*}})
+//    If this call throws, we already popped our cleanups
+// WIN32:   call i32 @"\01?TakesTwo@@YAHUA@@0@Z"
+// WIN32:   ret void
+//
+//    There should be one dtor call for unwinding from the second getA.
+// WIN32:   invoke x86_thiscallcc void @"\01??1A@@QAE@XZ"
+// WIN32: }
+
+void TakeRef(const A &a);
+int HasDeactivatedCleanups() {
+  return TakesTwo((TakeRef(A()), A()), (TakeRef(A()), A()));
+}
+
+// WIN32: define i32 @"\01?HasDeactivatedCleanups@@YAHXZ"() {{.*}} {
+// WIN32:   %[[isactive:.*]] = alloca i1
+// WIN32:   call x86_thiscallcc %struct.A* @"\01??0A@@QAE@XZ"
+// WIN32:   invoke void @"\01?TakeRef@@YAXABUA@@@Z"
+// WIN32:   invoke x86_thiscallcc %struct.A* @"\01??0A@@QAE@XZ"(%struct.A* %[[arg1:.*]])
+// WIN32:   store i1 true, i1* %[[isactive]]
+// WIN32:   invoke x86_thiscallcc %struct.A* @"\01??0A@@QAE@XZ"
+// WIN32:   invoke void @"\01?TakeRef@@YAXABUA@@@Z"
+// WIN32:   invoke x86_thiscallcc %struct.A* @"\01??0A@@QAE@XZ"
+// WIN32:   store i1 false, i1* %[[isactive]]
+// WIN32:   invoke i32 @"\01?TakesTwo@@YAHUA@@0@Z"
+//        Destroy the two const ref temporaries.
+// WIN32:   invoke x86_thiscallcc void @"\01??1A@@QAE@XZ"
+// WIN32:   call x86_thiscallcc void @"\01??1A@@QAE@XZ"
+// WIN32:   ret i32
+//
+//        Conditionally destroy arg1.
+// WIN32:   %[[cond:.*]] = load i1* %[[isactive]]
+// WIN32:   br i1 %[[cond]]
+// WIN32:   invoke x86_thiscallcc void @"\01??1A@@QAE@XZ"(%struct.A* %[[arg1]])
+// WIN32: }
+
+// Test putting the cleanups inside a conditional.
+int CouldThrow();
+int HasConditionalCleanup(bool cond) {
+  return (cond ? TakesTwo(A(), A()) : CouldThrow());
+}
+
+// WIN32: define i32 @"\01?HasConditionalCleanup@@YAH_N@Z"(i1 zeroext %{{.*}}) {{.*}} {
+// WIN32:   store i1 false
+// WIN32:   br i1
+//        No cleanups, so we call and then activate a cleanup if it succeeds.
+// WIN32:   call x86_thiscallcc %struct.A* @"\01??0A@@QAE@XZ"(%struct.A* %[[arg1:.*]])
+// WIN32:   store i1 true
+//        Now we have a cleanup for the first aggregate, so we invoke.
+// WIN32:   invoke x86_thiscallcc %struct.A* @"\01??0A@@QAE@XZ"(%struct.A* %{{.*}})
+//        Now we have no cleanups because TakeTwo will destruct both args.
+// WIN32:   call i32 @"\01?TakesTwo@@YAHUA@@0@Z"
+//        Still no cleanups, so call.
+// WIN32:   call i32 @"\01?CouldThrow@@YAHXZ"()
+//        Somewhere in the landing pad for our single invoke, call the dtor.
+// WIN32:   invoke x86_thiscallcc void @"\01??1A@@QAE@XZ"(%struct.A* %[[arg1]])
+// WIN32: }
+
+// Now test both.
+int HasConditionalDeactivatedCleanups(bool cond) {
+  return (cond ? TakesTwo((TakeRef(A()), A()), (TakeRef(A()), A())) : CouldThrow());
+}
+
+// WIN32: define i32 @"\01?HasConditionalDeactivatedCleanups@@YAH_N@Z"{{.*}} {
+// WIN32:   %[[arg1:.*]] = alloca %struct.A, align 4
+// WIN32:   alloca i1
+// WIN32:   %[[arg1_cond:.*]] = alloca i1
+//        Start all four cleanups as deactivated.
+// WIN32:   store i1 false
+// WIN32:   store i1 false
+// WIN32:   store i1 false
+// WIN32:   store i1 false
+// WIN32:   br i1
+//        True condition.
+// WIN32:   call x86_thiscallcc %struct.A* @"\01??0A@@QAE@XZ"
+// WIN32:   store i1 true
+// WIN32:   invoke void @"\01?TakeRef@@YAXABUA@@@Z"
+// WIN32:   invoke x86_thiscallcc %struct.A* @"\01??0A@@QAE@XZ"(%struct.A* %[[arg1]])
+// WIN32:   store i1 true, i1* %[[arg1_cond]]
+// WIN32:   invoke x86_thiscallcc %struct.A* @"\01??0A@@QAE@XZ"
+// WIN32:   store i1 true
+// WIN32:   invoke void @"\01?TakeRef@@YAXABUA@@@Z"
+// WIN32:   invoke x86_thiscallcc %struct.A* @"\01??0A@@QAE@XZ"
+// WIN32:   store i1 true
+// WIN32:   store i1 false, i1* %[[arg1_cond]]
+// WIN32:   invoke i32 @"\01?TakesTwo@@YAHUA@@0@Z"
+//        False condition.
+// WIN32:   invoke i32 @"\01?CouldThrow@@YAHXZ"()
+//        Two normal cleanups for TakeRef args.
+// WIN32:   invoke x86_thiscallcc void @"\01??1A@@QAE@XZ"
+// WIN32:   call x86_thiscallcc void @"\01??1A@@QAE@XZ"
+// WIN32:   ret i32
+//
+//        Somewhere in the landing pad soup, we conditionally destroy arg1.
+// WIN32:   %[[isactive:.*]] = load i1* %[[arg1_cond]]
+// WIN32:   br i1 %[[isactive]]
+// WIN32:   invoke x86_thiscallcc void @"\01??1A@@QAE@XZ"(%struct.A* %[[arg1]])
+// WIN32: }