[Clang][HIP] Warn when __AMDGCN_WAVEFRONT_SIZE is used in host code

clang/lib/Driver/ToolChains/AMDGPU.cpp

@@ -551,6 +551,17 @@ void RocmInstallationDetector::AddHIPIncludeArgs(const ArgList &DriverArgs,
     CC1Args.push_back(DriverArgs.MakeArgString(P));
   }
 
+  {
+    // This header implements diagnostics for problematic uses of
+    // device-specific macros. Since these diagnostics should be issued even
+    // when GPU headers are not included, this header is included separately.
+    SmallString<128> P(D.ResourceDir);
+    llvm::sys::path::append(P, "include");
+    CC1Args.push_back("-internal-isystem");
+    CC1Args.push_back(DriverArgs.MakeArgString(P));
+    CC1Args.append({"-include", "__clang_hip_device_macro_guards.h"});
+  }
+
   const auto HandleHipStdPar = [=, &DriverArgs, &CC1Args]() {
     StringRef Inc = getIncludePath();
     auto &FS = D.getVFS();

clang/lib/Headers/CMakeLists.txt

@@ -79,6 +79,7 @@ set(hip_files
   __clang_hip_math.h
   __clang_hip_stdlib.h
   __clang_hip_runtime_wrapper.h
+  __clang_hip_device_macro_guards.h
   )
 
 set(hlsl_h

clang/lib/Headers/__clang_hip_device_macro_guards.h

@@ -0,0 +1,55 @@
+/*===---- __clang_hip_device_macro_guards.h - guards for HIP device macros -===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+/*
+ * WARNING: This header is intended to be directly -include'd by
+ * the compiler and is not supposed to be included by users.
+ *
+ */
+
+#ifndef __CLANG_HIP_DEVICE_MACRO_GUARDS_H__
+#define __CLANG_HIP_DEVICE_MACRO_GUARDS_H__
+
+#if __HIP__
+#if !defined(__HIP_DEVICE_COMPILE__)
+// The __AMDGCN_WAVEFRONT_SIZE macros cannot hold meaningful values during host
+// compilation as devices are not initialized when the macros are defined and
+// there may indeed be devices with differing wavefront sizes in the same
+// system. This code issues diagnostics when the macros are used in host code.
+
+#undef __AMDGCN_WAVEFRONT_SIZE
+#undef __AMDGCN_WAVEFRONT_SIZE__
+
+// Reference __hip_device_macro_guard in a way that is legal in preprocessor
+// directives and does not affect the value so that appropriate diagnostics are
+// issued. Function calls, casts, or the comma operator would make the macro
+// illegal for use in preprocessor directives.
+#define __AMDGCN_WAVEFRONT_SIZE (!__hip_device_macro_guard ? 64 : 64)
+#define __AMDGCN_WAVEFRONT_SIZE__ (!__hip_device_macro_guard ? 64 : 64)
+
+// This function is referenced by the macro in device functions during host
+// compilation, it SHOULD NOT cause a diagnostic.
+__attribute__((device)) static constexpr int __hip_device_macro_guard(void) {
+  return -1;
+}
+
+// This function is referenced by the macro in host functions during host
+// compilation, it SHOULD cause a diagnostic.
+__attribute__((
+    host, deprecated("The __AMDGCN_WAVEFRONT_SIZE macros do not correspond "
+                     "to the device(s) when used in host code and may only "
+                     "be used in device code."))) static constexpr int
+__hip_device_macro_guard(void) {
+  return -1;
+}
+// TODO Change "deprecated" to "unavailable" to cause hard errors instead of
+// warnings.
+#endif
+#endif // __HIP__
+#endif // __CLANG_HIP_DEVICE_MACRO_GUARDS_H__

clang/test/Driver/hip-wavefront-size-host-diagnostics.hip

@@ -0,0 +1,52 @@
+// REQUIRES: amdgpu-registered-target
+// RUN: %clang -xhip --offload-arch=gfx1030 --offload-host-only -pedantic -nogpuinc -nogpulib -nobuiltininc -nostdinc -fsyntax-only -Xclang -verify=onhost %s
+// RUN: %clang -xhip --offload-arch=gfx1030 --offload-device-only -pedantic -nogpuinc -nogpulib -nobuiltininc -nostdinc -fsyntax-only -Xclang -verify=ondevice %s
+
+// ondevice-no-diagnostics
+
+#define WRAPPED __AMDGCN_WAVEFRONT_SIZE__
+
+__attribute__((host, device)) void use(int, const char*);
+
+template<int N> __attribute__((host, device)) int templatify(int x) {
+    return x + N;
+}
+
+// no warning expected
+#if defined(__HIP_DEVICE_COMPILE__) && (__AMDGCN_WAVEFRONT_SIZE__ == 64) && (__AMDGCN_WAVEFRONT_SIZE == 64)
+int foo(void);
+#endif
+
+// no warning expected
+__attribute__((device)) int device_var = __AMDGCN_WAVEFRONT_SIZE__;
+
+__attribute__((device))
+void device_fun() {
+    // no warnings expected
+    use(__AMDGCN_WAVEFRONT_SIZE, "device function");
+    use(__AMDGCN_WAVEFRONT_SIZE__, "device function");
+    use(WRAPPED, "device function");
+    use(templatify<__AMDGCN_WAVEFRONT_SIZE__>(42), "device function");
+}
+
+// warning expected
+int host_var = __AMDGCN_WAVEFRONT_SIZE__;  // onhost-warning {{'__hip_device_macro_guard' is deprecated: The __AMDGCN_WAVEFRONT_SIZE macros do not correspond to the device(s) when used in host code and may only be used in device code.}}
+
+__attribute__((host))
+void host_fun() {
+    // warnings expected
+    use(__AMDGCN_WAVEFRONT_SIZE, "host function");  // onhost-warning {{'__hip_device_macro_guard' is deprecated: The __AMDGCN_WAVEFRONT_SIZE macros do not correspond to the device(s) when used in host code and may only be used in device code.}}
+    use(__AMDGCN_WAVEFRONT_SIZE__, "host function");  // onhost-warning {{'__hip_device_macro_guard' is deprecated: The __AMDGCN_WAVEFRONT_SIZE macros do not correspond to the device(s) when used in host code and may only be used in device code.}}
+    use(WRAPPED, "host function");  // onhost-warning {{'__hip_device_macro_guard' is deprecated: The __AMDGCN_WAVEFRONT_SIZE macros do not correspond to the device(s) when used in host code and may only be used in device code.}}
+    use(templatify<__AMDGCN_WAVEFRONT_SIZE__>(42), "host function");  // onhost-warning {{'__hip_device_macro_guard' is deprecated: The __AMDGCN_WAVEFRONT_SIZE macros do not correspond to the device(s) when used in host code and may only be used in device code.}}
+}
+
+__attribute((host, device))
+void host_device_fun() {
+    // warnings expected
+    use(__AMDGCN_WAVEFRONT_SIZE__, "host device function");  // onhost-warning {{'__hip_device_macro_guard' is deprecated: The __AMDGCN_WAVEFRONT_SIZE macros do not correspond to the device(s) when used in host code and may only be used in device code.}}
+    use(WRAPPED, "host device function");  // onhost-warning {{'__hip_device_macro_guard' is deprecated: The __AMDGCN_WAVEFRONT_SIZE macros do not correspond to the device(s) when used in host code and may only be used in device code.}}
+    use(templatify<__AMDGCN_WAVEFRONT_SIZE__>(42), "host device function");  // onhost-warning {{'__hip_device_macro_guard' is deprecated: The __AMDGCN_WAVEFRONT_SIZE macros do not correspond to the device(s) when used in host code and may only be used in device code.}}
+}
+
+// onhost-note@__clang_hip_device_macro_guards.h:45 0+ {{'__hip_device_macro_guard' has been explicitly marked deprecated here}}

clang/test/Preprocessor/predefined-arch-macros.c

@@ -4399,7 +4399,6 @@
 // RUN: %clang -x hip -E -dM %s -o - 2>&1 --offload-host-only -nogpulib \
 // RUN:     -nogpuinc --offload-arch=gfx803 -target x86_64-unknown-linux \
 // RUN:   | FileCheck -match-full-lines %s -check-prefixes=CHECK_HIP_HOST
-// CHECK_HIP_HOST: #define __AMDGCN_WAVEFRONT_SIZE__ 64
 // CHECK_HIP_HOST: #define __AMDGPU__ 1
 // CHECK_HIP_HOST: #define __AMD__ 1