Add MS Mangling for OpenCL Pipe types, add mangling test.

SPIRV2.0 Spec only specifies Linux mangling, however our downstream has
use for a Windows mangling for these types.

Unfortunately, the SPIRV
spec specifies a single mangling for all pipe types, despite clang
allowing overloading on these types.  Because of this, this patch
chooses to mangle the read/writability and element type for the windows
mangling.

The windows manglings in the test all demangle according to demangler:
"void __cdecl test1(struct __clang::ocl_pipe<int,1>)
"void __cdecl test2(struct __clang::ocl_pipe<float,0>)
"void __cdecl test2(struct __clang::ocl_pipe<int,1>)
"void __cdecl test3(struct __clang::ocl_pipe<int const,1>)
"void __cdecl test4(struct __clang::ocl_pipe<union
__clang::__vector<unsigned char,3>,1>)
"void __cdecl test5(struct __clang::ocl_pipe<union
__clang::__vector<int,4>,1>)
"void __cdecl test_reserved_read_pipe(struct __clang::_ASCLglobal<struct
Person > * __ptr64,struct __clang::ocl_pipe<struct Person,1>)

Differential Revision: https://reviews.llvm.org/D75685

clang/lib/AST/MicrosoftMangle.cpp

@@ -2940,11 +2940,17 @@ void MicrosoftCXXNameMangler::mangleType(const AtomicType *T, Qualifiers,
 
 void MicrosoftCXXNameMangler::mangleType(const PipeType *T, Qualifiers,
                                          SourceRange Range) {
-  DiagnosticsEngine &Diags = Context.getDiags();
-  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
-    "cannot mangle this OpenCL pipe type yet");
-  Diags.Report(Range.getBegin(), DiagID)
-    << Range;
+  QualType ElementType = T->getElementType();
+
+  llvm::SmallString<64> TemplateMangling;
+  llvm::raw_svector_ostream Stream(TemplateMangling);
+  MicrosoftCXXNameMangler Extra(Context, Stream);
+  Stream << "?$";
+  Extra.mangleSourceName("ocl_pipe");
+  Extra.mangleType(ElementType, Range, QMM_Escape);
+  Extra.mangleIntegerLiteral(llvm::APSInt::get(T->isReadOnly()), true);
+
+  mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__clang"});
 }
 
 void MicrosoftMangleContextImpl::mangleCXXName(GlobalDecl GD,

clang/test/CodeGenOpenCL/pipe_types_mangling.cl

@@ -0,0 +1,72 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -O0 -cl-std=clc++ -o - %s | FileCheck %s --check-prefixes=LINUX
+// RUN: %clang_cc1 -triple x86_64-unknown-windows-pc -emit-llvm -O0 -cl-std=clc++ -o - %s -DWIN| FileCheck %s --check-prefixes=WINDOWS
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -O0 -cl-std=CL2.0 -o - %s | FileCheck %s --check-prefixes=UNMANGLED,OCLLINUX
+// RUN: %clang_cc1 -triple x86_64-unknown-windows-pc -emit-llvm -O0 -cl-std=CL2.0 -o - %s -DWIN| FileCheck %s --check-prefixes=UNMANGLED,OCLWINDOWS
+
+typedef unsigned char __attribute__((ext_vector_type(3))) uchar3;
+typedef int __attribute__((ext_vector_type(4))) int4;
+
+void test1(read_only pipe int p) {
+// LINUX: define void @_Z5test18ocl_pipe
+// WINDOWS: define dso_local void @"?test1@@YAXU?$ocl_pipe@H$00@__clang@@@Z"
+// UNMANGLED: define {{.*}}void @test1(
+}
+
+__attribute__((overloadable))
+void test2(write_only pipe float p) {
+// LINUX: define void @_Z5test28ocl_pipe
+// WINDOWS: define dso_local void @"?test2@@YAXU?$ocl_pipe@M$0A@@__clang@@@Z"
+// Note: overloadable attribute makes OpenCL Linux still mangle this,
+// but we cannot overload on pipe still.
+// OCLLINUX: define void @_Z5test28ocl_pipe
+// OCLWINDOWS: define dso_local void @"?test2@@$$J0YAXU?$ocl_pipe@M$0A@@__clang@@@Z"
+}
+
+#ifdef WIN
+// SPIR Spec specifies mangling on pipes that doesn't include the element type
+//  or write/read. Our Windows mangling does, so make sure this still works.
+__attribute__((overloadable))
+void test2(read_only pipe int p) {
+// WINDOWS: define dso_local void @"?test2@@YAXU?$ocl_pipe@H$00@__clang@@@Z"
+// OCLWINDOWS: define dso_local void @"?test2@@$$J0YAXU?$ocl_pipe@H$00@__clang@@@Z"
+}
+#endif
+
+
+void test3(read_only pipe const int p) {
+// LINUX: define void @_Z5test38ocl_pipe
+// WINDOWS: define dso_local void @"?test3@@YAXU?$ocl_pipe@$$CBH$00@__clang@@@Z"
+// UNMANGLED: define {{.*}}void @test3(
+}
+
+void test4(read_only pipe uchar3 p) {
+// LINUX: define void @_Z5test48ocl_pipe
+// WINDOWS: define dso_local void @"?test4@@YAXU?$ocl_pipe@T?$__vector@E$02@__clang@@$00@__clang@@@Z"
+// UNMANGLED: define {{.*}}void @test4(
+}
+
+void test5(read_only pipe int4 p) {
+// LINUX: define void @_Z5test58ocl_pipe
+// WINDOWS: define dso_local void @"?test5@@YAXU?$ocl_pipe@T?$__vector@H$03@__clang@@$00@__clang@@@Z"
+// UNMANGLED: define {{.*}}void @test5(
+}
+
+typedef read_only pipe int MyPipe;
+kernel void test6(MyPipe p) {
+// LINUX: define spir_kernel void @test6
+// WINDOWS: define dso_local spir_kernel void @test6
+// UNMANGLED: define {{.*}}void @test6(
+}
+
+struct Person {
+  const char *Name;
+  bool isFemale;
+  int ID;
+};
+
+void test_reserved_read_pipe(global struct Person *SDst,
+                             read_only pipe struct Person SPipe) {
+// LINUX: define void @_Z23test_reserved_read_pipePU8CLglobal6Person8ocl_pipe
+// WINDOWS: define dso_local void @"?test_reserved_read_pipe@@YAXPEAU?$_ASCLglobal@$$CAUPerson@@@__clang@@U?$ocl_pipe@UPerson@@$00@2@@Z"
+// UNMANGLED: define {{.*}}void @test_reserved_read_pipe(
+}