r328362 - [CUDA] Fixed false error reporting in case of calling H->G->HD->D.

[Artem Belevich via cfe-commits]

Author: tra
Date: Fri Mar 23 12:49:03 2018
New Revision: 328362

URL: http://llvm.org/viewvc/llvm-project?rev=328362&view=rev
Log:
[CUDA] Fixed false error reporting in case of calling H->G->HD->D.

Launching a kernel from the host code does not generate code for the
kernel itself. This fixes an issue with clang erroneously reporting
an error for a HD->D call from within the kernel.

Differential Revision: https://reviews.llvm.org/D44837

Modified:
    cfe/trunk/lib/Sema/SemaCUDA.cpp
    cfe/trunk/test/SemaCUDA/call-device-fn-from-host.cu

Modified: cfe/trunk/lib/Sema/SemaCUDA.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaCUDA.cpp?rev=328362&r1=328361&r2=328362&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaCUDA.cpp (original)
+++ cfe/trunk/lib/Sema/SemaCUDA.cpp Fri Mar 23 12:49:03 2018
@@ -790,9 +790,12 @@ bool Sema::CheckCUDACall(SourceLocation
   // If the caller is known-emitted, mark the callee as known-emitted.
   // Otherwise, mark the call in our call graph so we can traverse it later.
   bool CallerKnownEmitted = IsKnownEmitted(*this, Caller);
-  if (CallerKnownEmitted)
-    MarkKnownEmitted(*this, Caller, Callee, Loc);
-  else {
+  if (CallerKnownEmitted) {
+    // Host-side references to a __global__ function refer to the stub, so the
+    // function itself is never emitted and therefore should not be marked.
+    if (getLangOpts().CUDAIsDevice || IdentifyCUDATarget(Callee) != CFT_Global)
+      MarkKnownEmitted(*this, Caller, Callee, Loc);
+  } else {
     // If we have
     //   host fn calls kernel fn calls host+device,
     // the HD function does not get instantiated on the host.  We model this by

Modified: cfe/trunk/test/SemaCUDA/call-device-fn-from-host.cu
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCUDA/call-device-fn-from-host.cu?rev=328362&r1=328361&r2=328362&view=diff
==============================================================================
--- cfe/trunk/test/SemaCUDA/call-device-fn-from-host.cu (original)
+++ cfe/trunk/test/SemaCUDA/call-device-fn-from-host.cu Fri Mar 23 12:49:03 2018
@@ -83,3 +83,10 @@ template <typename T>
 __host__ __device__ void fn_ptr_template() {
   auto* ptr = &device_fn;  // Not an error because the template isn't instantiated.
 }
+
+// Launching a kernel from a host function does not result in code generation
+// for it, so calling HD function which calls a D function should not trigger
+// errors.
+static __host__ __device__ void hd_func() { device_fn(); }
+__global__ void kernel() { hd_func(); }
+void host_func(void) { kernel<<<1, 1>>>(); }