[Clang][HIP] Reapply: Deprecate the AMDGCN_WAVEFRONT_SIZE macros

[ritter-x2a]

So far, these macros can be used in contexts where no meaningful
wavefront size is available. We therefore deprecate these macros, to
replace them with a more resilient interface to access wavefront size
information where it is available.

Reapplies #112849 with a fix for the non-hermetic clang test that failed
on Mac after the revert in #115499.

For SWDEV-491529.

[llvmbot]

@llvm/pr-subscribers-clang-driver
@llvm/pr-subscribers-backend-amdgpu

@llvm/pr-subscribers-clang

Author: Fabian Ritter (ritter-x2a)

Changes

So far, these macros can be used in contexts where no meaningful
wavefront size is available. We therefore deprecate these macros, to
replace them with a more resilient interface to access wavefront size
information where it is available.

Reapplies #112849 with a fix for the non-hermetic clang test that failed
on Mac after the revert in #115499.

For SWDEV-491529.

---

Full diff: https://github.com/llvm/llvm-project/pull/115507.diff

5 Files Affected:

• (modified) clang/docs/AMDGPUSupport.rst (+2-2)
• (modified) clang/docs/HIPSupport.rst (+1-1)
• (modified) clang/include/clang/Basic/MacroBuilder.h (+7-1)
• (modified) clang/lib/Basic/Targets/AMDGPU.cpp (+6-3)
• (added) clang/test/Driver/hip-wavefront-size-deprecation-diagnostics.hip (+115)

diff --git a/clang/docs/AMDGPUSupport.rst b/clang/docs/AMDGPUSupport.rst
index e63c0e1ba7d67b..3eada5f900613a 100644
--- a/clang/docs/AMDGPUSupport.rst
+++ b/clang/docs/AMDGPUSupport.rst
@@ -50,9 +50,9 @@ Predefined Macros
    * - ``__AMDGCN_UNSAFE_FP_ATOMICS__``
      - Defined if unsafe floating-point atomics are allowed.
    * - ``__AMDGCN_WAVEFRONT_SIZE__``
-     - Defines the wavefront size. Allowed values are 32 and 64.
+     - Defines the wavefront size. Allowed values are 32 and 64 (deprecated).
    * - ``__AMDGCN_WAVEFRONT_SIZE``
-     - Alias to ``__AMDGCN_WAVEFRONT_SIZE__``. To be deprecated.
+     - Alias to ``__AMDGCN_WAVEFRONT_SIZE__`` (deprecated).
    * - ``__HAS_FMAF__``
      - Defined if FMAF instruction is available (deprecated).
    * - ``__HAS_LDEXPF__``
diff --git a/clang/docs/HIPSupport.rst b/clang/docs/HIPSupport.rst
index e26297c7af97ac..e830acd8dd85c0 100644
--- a/clang/docs/HIPSupport.rst
+++ b/clang/docs/HIPSupport.rst
@@ -178,7 +178,7 @@ Predefined Macros
 
 Note that some architecture specific AMDGPU macros will have default values when
 used from the HIP host compilation. Other :doc:`AMDGPU macros <AMDGPUSupport>`
-like ``__AMDGCN_WAVEFRONT_SIZE__`` will default to 64 for example.
+like ``__AMDGCN_WAVEFRONT_SIZE__`` (deprecated) will default to 64 for example.
 
 Compilation Modes
 =================
diff --git a/clang/include/clang/Basic/MacroBuilder.h b/clang/include/clang/Basic/MacroBuilder.h
index 96e67cbbfa3f21..d83f27c236e3d8 100644
--- a/clang/include/clang/Basic/MacroBuilder.h
+++ b/clang/include/clang/Basic/MacroBuilder.h
@@ -26,8 +26,14 @@ class MacroBuilder {
   MacroBuilder(raw_ostream &Output) : Out(Output) {}
 
   /// Append a \#define line for macro of the form "\#define Name Value\n".
-  void defineMacro(const Twine &Name, const Twine &Value = "1") {
+  /// If DeprecationMsg is provided, also append a pragma to deprecate the
+  /// defined macro.
+  void defineMacro(const Twine &Name, const Twine &Value = "1",
+                   Twine DeprecationMsg = "") {
     Out << "#define " << Name << ' ' << Value << '\n';
+    if (!DeprecationMsg.isTriviallyEmpty())
+      Out << "#pragma clang deprecated(" << Name << ", \"" << DeprecationMsg
+          << "\")\n";
   }
 
   /// Append a \#undef line for Name.  Name should be of the form XXX
diff --git a/clang/lib/Basic/Targets/AMDGPU.cpp b/clang/lib/Basic/Targets/AMDGPU.cpp
index 078819183afdac..99f8f2944e2796 100644
--- a/clang/lib/Basic/Targets/AMDGPU.cpp
+++ b/clang/lib/Basic/Targets/AMDGPU.cpp
@@ -337,9 +337,12 @@ void AMDGPUTargetInfo::getTargetDefines(const LangOptions &Opts,
   if (hasFastFMA())
     Builder.defineMacro("FP_FAST_FMA");
 
-  Builder.defineMacro("__AMDGCN_WAVEFRONT_SIZE__", Twine(WavefrontSize));
-  // ToDo: deprecate this macro for naming consistency.
-  Builder.defineMacro("__AMDGCN_WAVEFRONT_SIZE", Twine(WavefrontSize));
+  Builder.defineMacro("__AMDGCN_WAVEFRONT_SIZE__", Twine(WavefrontSize),
+                      "compile-time-constant access to the wavefront size will "
+                      "be removed in a future release");
+  Builder.defineMacro("__AMDGCN_WAVEFRONT_SIZE", Twine(WavefrontSize),
+                      "compile-time-constant access to the wavefront size will "
+                      "be removed in a future release");
   Builder.defineMacro("__AMDGCN_CUMODE__", Twine(CUMode));
 }
 
diff --git a/clang/test/Driver/hip-wavefront-size-deprecation-diagnostics.hip b/clang/test/Driver/hip-wavefront-size-deprecation-diagnostics.hip
new file mode 100644
index 00000000000000..8a60f5a150048f
--- /dev/null
+++ b/clang/test/Driver/hip-wavefront-size-deprecation-diagnostics.hip
@@ -0,0 +1,115 @@
+// REQUIRES: amdgpu-registered-target
+// RUN: %clang -xhip --offload-arch=gfx1030 --offload-host-only -pedantic -nogpuinc -nogpulib -nobuiltininc -fsyntax-only -Xclang -verify %s
+// RUN: %clang -xhip --offload-arch=gfx1030 --offload-device-only -pedantic -nogpuinc -nogpulib -nobuiltininc -fsyntax-only -Xclang -verify %s
+
+// Test that deprecation warnings for the wavefront size macro are emitted properly.
+
+#define WRAPPED __AMDGCN_WAVEFRONT_SIZE__
+
+#define DOUBLE_WRAPPED (WRAPPED)
+
+template <bool C, class T = void> struct my_enable_if {};
+
+template <class T> struct my_enable_if<true, T> {
+  typedef T type;
+};
+
+__attribute__((host, device)) void use(int, const char*);
+
+template<int N> __attribute__((host, device)) int templatify(int x) {
+    return x + N;
+}
+
+__attribute__((device)) const int GlobalConst = __AMDGCN_WAVEFRONT_SIZE__; // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+constexpr int GlobalConstExpr = __AMDGCN_WAVEFRONT_SIZE__; // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+
+#if defined(__HIP_DEVICE_COMPILE__) && (__AMDGCN_WAVEFRONT_SIZE__ == 64) // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+int foo(void);
+#endif
+
+__attribute__((device)) int device_var = __AMDGCN_WAVEFRONT_SIZE__; // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+
+__attribute__((device))
+void device_fun() {
+    use(__AMDGCN_WAVEFRONT_SIZE, "device function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE' has been marked as deprecated}}
+    use(__AMDGCN_WAVEFRONT_SIZE__, "device function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(WRAPPED, "device function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(DOUBLE_WRAPPED, "device function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(templatify<__AMDGCN_WAVEFRONT_SIZE__>(42), "device function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(GlobalConst, "device function");
+    use(GlobalConstExpr, "device function");
+}
+
+__attribute__((global))
+void global_fun() {
+    // no warnings expected
+    use(__AMDGCN_WAVEFRONT_SIZE, "global function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE' has been marked as deprecated}}
+    use(__AMDGCN_WAVEFRONT_SIZE__, "global function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(WRAPPED, "global function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(DOUBLE_WRAPPED, "global function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(templatify<__AMDGCN_WAVEFRONT_SIZE__>(42), "global function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+}
+
+int host_var = __AMDGCN_WAVEFRONT_SIZE__; // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+int host_var_alt = __AMDGCN_WAVEFRONT_SIZE; // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE' has been marked as deprecated}}
+int host_var_wrapped = WRAPPED; // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+int host_var_double_wrapped = DOUBLE_WRAPPED; // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+
+__attribute__((host))
+void host_fun() {
+    use(__AMDGCN_WAVEFRONT_SIZE, "host function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE' has been marked as deprecated}}
+    use(__AMDGCN_WAVEFRONT_SIZE__, "host function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(WRAPPED, "host function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(DOUBLE_WRAPPED, "host function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(templatify<__AMDGCN_WAVEFRONT_SIZE__>(42), "host function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(GlobalConst, "host function");
+    use(GlobalConstExpr, "host function");
+}
+
+__attribute((host, device))
+void host_device_fun() {
+    use(__AMDGCN_WAVEFRONT_SIZE__, "host device function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(WRAPPED, "host device function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(DOUBLE_WRAPPED, "host device function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    use(templatify<__AMDGCN_WAVEFRONT_SIZE__>(42), "host device function"); // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+}
+
+template <unsigned int OuterWarpSize = __AMDGCN_WAVEFRONT_SIZE__> // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+class FunSelector {
+public:
+    template<unsigned int FunWarpSize = OuterWarpSize>
+    __attribute__((device))
+    auto fun(void)
+        -> typename my_enable_if<(FunWarpSize <= __AMDGCN_WAVEFRONT_SIZE__), void>::type // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    {
+        use(1, "yay!");
+    }
+
+    template<unsigned int FunWarpSize = OuterWarpSize>
+    __attribute__((device))
+    auto fun(void)
+        -> typename my_enable_if<(FunWarpSize > __AMDGCN_WAVEFRONT_SIZE__), void>::type // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    {
+        use(0, "nay!");
+    }
+};
+
+__attribute__((device))
+void device_fun_selector_user() {
+    FunSelector<> f;
+    f.fun<>();
+    f.fun<1>();
+    f.fun<1000>();
+
+    my_enable_if<(1 <= __AMDGCN_WAVEFRONT_SIZE__), int>::type x = 42; // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+}
+
+__attribute__((device)) my_enable_if<(1 <= __AMDGCN_WAVEFRONT_SIZE__), int>::type DeviceFunTemplateRet(void) { // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    return 42;
+}
+
+__attribute__((device)) int DeviceFunTemplateArg(my_enable_if<(1 <= __AMDGCN_WAVEFRONT_SIZE__), int>::type x) { // expected-warning {{macro '__AMDGCN_WAVEFRONT_SIZE__' has been marked as deprecated}}
+    return x;
+}
+
+// expected-note@* 0+ {{macro marked 'deprecated' here}}