[Clang][HIP] Suppress availability diagnostics for mismatched host/device overloads

clang/lib/Sema/SemaAvailability.cpp

@@ -20,6 +20,7 @@
 #include "clang/Sema/DelayedDiagnostic.h"
 #include "clang/Sema/ScopeInfo.h"
 #include "clang/Sema/Sema.h"
+#include "clang/Sema/SemaCUDA.h"
 #include "clang/Sema/SemaObjC.h"
 #include "llvm/ADT/StringRef.h"
 #include <optional>
@@ -156,6 +157,58 @@ static bool ShouldDiagnoseAvailabilityInContext(
     }
   }
 
+  if (S.getLangOpts().CUDA || S.getLangOpts().HIP) {
+    // In CUDA/HIP, do not diagnose uses of unavailable host or device function
+    // overloads when they occur in the context of a Decl with an explicitly
+    // given opposite target.
+    // We encounter this if the OffendingDecl is used outside of a function
+    // body, e.g., in template arguments for a function's return or parameter
+    // types. In this case, overloads of the called function are resolved as if
+    // in a host-device context, i.e., the device overload is chosen in the
+    // device compilation phase and the host overload in the host compilation
+    // phase. As code is only generated for the variant with matching targets,
+    // an availabiliy diagnostic for the variant with non-matching targets would
+    // be spurious.
+
+    if (auto *OffendingFunDecl = llvm::dyn_cast<FunctionDecl>(OffendingDecl)) {
+      Decl *ActualCtx = Ctx;
+      if (auto *FTD = llvm::dyn_cast<FunctionTemplateDecl>(Ctx)) {
+        // Attributes of template Decls are only on the templated Decl
+        ActualCtx = FTD->getTemplatedDecl();
+      }
+      if (auto *CtxFun = llvm::dyn_cast<FunctionDecl>(ActualCtx)) {
+        auto TargetIs = [&S](const FunctionDecl *FD, CUDAFunctionTarget FT) {
+          return S.CUDA().IdentifyTarget(FD, /* IgnoreImplicitHDAttr */ true) ==
+                 FT;
+        };
+
+        bool CtxIsHost = TargetIs(CtxFun, CUDAFunctionTarget::Host);
+        bool CtxIsDevice = TargetIs(CtxFun, CUDAFunctionTarget::Device);
+
+        bool OffendingDeclIsHost =
+            TargetIs(OffendingFunDecl, CUDAFunctionTarget::Host);
+        bool OffendingDeclIsDevice =
+            TargetIs(OffendingFunDecl, CUDAFunctionTarget::Device);
+
+        // There is a way to call a device function from host code (and vice
+        // versa, analogously) that passes semantic analysis: As constexprs,
+        // when there is no host overload. In this case, a diagnostic is
+        // necessary. Characteristic for this situation is that the device
+        // function will also be used in a host context during host compilation.
+        // Therefore, only suppress diagnostics if a host function is used in a
+        // device context during host compilation or a device function is used
+        // in a host context during device compilation.
+        bool CompilingForDevice = S.getLangOpts().CUDAIsDevice;
+        bool CompilingForHost = !CompilingForDevice;
+
+        if ((OffendingDeclIsHost && CtxIsDevice && CompilingForHost) ||
+            (OffendingDeclIsDevice && CtxIsHost && CompilingForDevice)) {
+          return false;
+        }
+      }
+    }
+  }
+
   // Checks if we should emit the availability diagnostic in the context of C.
   auto CheckContext = [&](const Decl *C) {
     if (K == AR_NotYetIntroduced) {

clang/test/SemaCUDA/suppress-availability-warnings-mismatched-attributes.cu

@@ -0,0 +1,149 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fsyntax-only -verify=expected,onhost %s
+// RUN: %clang_cc1 -triple nvptx64-nvidia-cuda -fsyntax-only -fcuda-is-device -verify=expected,ondevice %s
+
+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 x);
+
+__attribute__((device)) constexpr int OverloadFunHostDepr(void) { return 1; }
+__attribute__((host, deprecated("Host variant"))) constexpr int OverloadFunHostDepr(void) { return 1; } // expected-note 0+ {{has been explicitly marked deprecated here}}
+
+
+__attribute__((device, deprecated("Device variant"))) constexpr int OverloadFunDeviceDepr(void) { return 1; } // expected-note 0+ {{has been explicitly marked deprecated here}}
+__attribute__((host)) constexpr int OverloadFunDeviceDepr(void) { return 1; }
+
+
+template<typename T>
+__attribute__((device)) constexpr T TemplateOverloadFun(void) { return 1; }
+
+template<typename T>
+__attribute__((host, deprecated("Host variant"))) constexpr T TemplateOverloadFun(void) { return 1; } // expected-note 0+ {{has been explicitly marked deprecated here}}
+
+
+__attribute__((device, deprecated)) constexpr int // expected-note 0+ {{has been explicitly marked deprecated here}}
+DeviceOnlyFunDeprecated(void) { return 1; }
+
+__attribute__((host, deprecated)) constexpr int // expected-note 0+ {{has been explicitly marked deprecated here}}
+HostOnlyFunDeprecated(void) { return 1; }
+
+class FunSelector {
+public:
+  template<int X> __attribute__((device))
+  auto devicefun(void) -> typename my_enable_if<(X == OverloadFunHostDepr()), int>::type {
+    return 1;
+  }
+
+  template<int X> __attribute__((device))
+  auto devicefun(void) -> typename my_enable_if<(X != OverloadFunHostDepr()), int>::type {
+      return 0;
+  }
+
+  template<int X> __attribute__((device))
+  auto devicefun_wrong(void) -> typename my_enable_if<(X == OverloadFunDeviceDepr()), int>::type { // ondevice-warning {{'OverloadFunDeviceDepr' is deprecated: Device variant}}
+    return 1;
+  }
+
+  template<int X> __attribute__((device))
+  auto devicefun_wrong(void) -> typename my_enable_if<(X != OverloadFunDeviceDepr()), int>::type { // ondevice-warning {{'OverloadFunDeviceDepr' is deprecated: Device variant}}
+      return 0;
+  }
+
+  template<int X> __attribute__((host))
+  auto hostfun(void) -> typename my_enable_if<(X == OverloadFunDeviceDepr()), int>::type {
+    return 1;
+  }
+
+  template<int X> __attribute__((host))
+  auto hostfun(void) -> typename my_enable_if<(X != OverloadFunDeviceDepr()), int>::type {
+      return 0;
+  }
+
+  template<int X> __attribute__((host))
+  auto hostfun_wrong(void) -> typename my_enable_if<(X == OverloadFunHostDepr()), int>::type { // onhost-warning {{'OverloadFunHostDepr' is deprecated: Host variant}}
+    return 1;
+  }
+
+  template<int X> __attribute__((host))
+  auto hostfun_wrong(void) -> typename my_enable_if<(X != OverloadFunHostDepr()), int>::type { // onhost-warning {{'OverloadFunHostDepr' is deprecated: Host variant}}
+      return 0;
+  }
+};
+
+
+// These should not be diagnosed since the device overload of
+// OverloadFunHostDepr is not deprecated:
+__attribute__((device)) my_enable_if<(OverloadFunHostDepr() > 0), int>::type
+DeviceUserOverloadFunHostDepr1(void) { return 2; }
+
+my_enable_if<(OverloadFunHostDepr() > 0), int>::type __attribute__((device))
+DeviceUserOverloadFunHostDepr2(void) { return 2; }
+
+__attribute__((device))
+my_enable_if<(OverloadFunHostDepr() > 0), int>::type constexpr
+DeviceUserOverloadFunHostDeprConstexpr(void) { return 2; }
+
+
+// Analogously for OverloadFunDeviceDepr:
+__attribute__((host)) my_enable_if<(OverloadFunDeviceDepr() > 0), int>::type
+DeviceUserOverloadFunDeviceDepr1(void) { return 2; }
+
+my_enable_if<(OverloadFunDeviceDepr() > 0), int>::type __attribute__((host))
+DeviceUserOverloadFunDeviceDepr2(void) { return 2; }
+
+__attribute__((host))
+my_enable_if<(OverloadFunDeviceDepr() > 0), int>::type constexpr
+DeviceUserOverloadFunDeviceDeprConstexpr(void) { return 2; }
+
+
+// Actual uses of the deprecated overloads should be diagnosed:
+__attribute__((host, device)) my_enable_if<(OverloadFunHostDepr() > 0), int>::type // onhost-warning {{'OverloadFunHostDepr' is deprecated: Host variant}}
+HostDeviceUserOverloadFunHostDepr(void) { return 3; }
+
+__attribute__((host)) my_enable_if<(OverloadFunHostDepr() > 0), int>::type constexpr // onhost-warning {{'OverloadFunHostDepr' is deprecated: Host variant}}
+HostUserOverloadFunHostDeprConstexpr(void) { return 3; }
+
+__attribute__((device)) my_enable_if<(OverloadFunDeviceDepr() > 0), int>::type constexpr // ondevice-warning {{'OverloadFunDeviceDepr' is deprecated: Device variant}}
+HostUserOverloadFunDeviceDeprConstexpr(void) { return 3; }
+
+
+// Making the offending decl a template shouldn't change anything:
+__attribute__((host)) my_enable_if<(TemplateOverloadFun<int>() > 0), int>::type // onhost-warning {{'TemplateOverloadFun<int>' is deprecated: Host variant}}
+HostUserTemplateOverloadFun(void) { return 3; }
+
+__attribute__((device)) my_enable_if<(TemplateOverloadFun<int>() > 0), int>::type
+DeviceUserTemplateOverloadFun(void) { return 3; }
+
+
+// If the constexpr function is actually called from the mismatched context, diagnostics should be issued:
+__attribute__((host))
+my_enable_if<(DeviceOnlyFunDeprecated() > 0), int>::type constexpr // onhost-warning {{'DeviceOnlyFunDeprecated' is deprecated}}
+HostUserDeviceOnlyFunDeprecated(void) { return 3; }
+
+__attribute__((device))
+my_enable_if<(HostOnlyFunDeprecated() > 0), int>::type constexpr // ondevice-warning {{'HostOnlyFunDeprecated' is deprecated}}
+DeviceUserHostOnlyFunDeprecated(void) { return 3; }
+
+// Diagnostics for uses in function bodies should work as expected:
+__attribute__((device, deprecated)) constexpr int DeviceVarConstDepr = 1; // expected-note 0+ {{has been explicitly marked deprecated here}}
+
+__attribute__((host)) void HostUser(void) {
+  use(DeviceVarConstDepr); // expected-warning {{'DeviceVarConstDepr' is deprecated}}
+  use(HostOnlyFunDeprecated()); // expected-warning {{'HostOnlyFunDeprecated' is deprecated}}
+  use(OverloadFunHostDepr()); // expected-warning {{'OverloadFunHostDepr' is deprecated: Host variant}}
+  use(TemplateOverloadFun<int>()); // expected-warning {{'TemplateOverloadFun<int>' is deprecated: Host variant}}
+
+  use(OverloadFunDeviceDepr());
+}
+
+__attribute__((device)) void DeviceUser(void) {
+  use(DeviceVarConstDepr); // expected-warning {{'DeviceVarConstDepr' is deprecated}}
+  use(DeviceOnlyFunDeprecated()); // expected-warning {{'DeviceOnlyFunDeprecated' is deprecated}}
+  use(OverloadFunDeviceDepr()); // expected-warning {{'OverloadFunDeviceDepr' is deprecated: Device variant}}
+
+  use(OverloadFunHostDepr());
+  use(TemplateOverloadFun<int>());
+}