[PATCH] D100609: [Offload][OpenMP][CUDA] Allow fembed-bitcode for device offload

[Johannes Doerfert via Phabricator via cfe-commits]

jdoerfert created this revision.
jdoerfert added a reviewer: tra.
Herald added subscribers: guansong, yaxunl.
Herald added a reviewer: bollu.
jdoerfert requested review of this revision.
Herald added a subscriber: sstefan1.
Herald added a project: clang.

This is a fix for the problem reported here:
https://lists.llvm.org/pipermail/llvm-dev/2021-March/149529.html

That is, the target information was missing when we embedded bitcode and
that caused the NVPTX backend to fail.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D100609

Files:
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/test/Driver/embed-bitcode-nvptx.cu


Index: clang/test/Driver/embed-bitcode-nvptx.cu
===================================================================
--- /dev/null
+++ clang/test/Driver/embed-bitcode-nvptx.cu
@@ -0,0 +1,8 @@
+// RUN: %clang -Xclang -triple -Xclang nvptx64 -S -Xclang -target-feature -Xclang +ptx70 -fembed-bitcode=all --cuda-device-only -nocudalib -nocudainc %s -o - | FileCheck %s
+// REQUIRES: nvptx-registered-target
+//
+// CHECK:.global .align 1 .b8 llvm_$_embedded_$_module[
+
+__device__ void foo(int mask) {
+  __nvvm_bar_warp_sync(mask);
+}
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -4295,6 +4295,9 @@
   // Select the appropriate action.
   RewriteKind rewriteKind = RK_None;
 
+  bool isDeviceOffloadAction = !(JA.isDeviceOffloading(Action::OFK_None) ||
+                                  JA.isDeviceOffloading(Action::OFK_Host));
+
   // If CollectArgsForIntegratedAssembler() isn't called below, claim the args
   // it claims when not running an assembler. Otherwise, clang would emit
   // "argument unused" warnings for assembler flags when e.g. adding "-E" to
@@ -4401,9 +4404,6 @@
       CmdArgs.push_back("-emit-llvm-uselists");
 
     // Device-side jobs do not support LTO.
-    bool isDeviceOffloadAction = !(JA.isDeviceOffloading(Action::OFK_None) ||
-                                   JA.isDeviceOffloading(Action::OFK_Host));
-
     if (D.isUsingLTO() && !isDeviceOffloadAction) {
       Args.AddLastArg(CmdArgs, options::OPT_flto, options::OPT_flto_EQ);
       CmdArgs.push_back("-flto-unit");
@@ -4436,7 +4436,15 @@
     // Add flags implied by -fembed-bitcode.
     Args.AddLastArg(CmdArgs, options::OPT_fembed_bitcode_EQ);
     // Disable all llvm IR level optimizations.
-    CmdArgs.push_back("-disable-llvm-passes");
+    if (!isDeviceOffloadAction) {
+      CmdArgs.push_back("-disable-llvm-passes");
+    } else  {
+      std::string CPU = getCPUName(Args, Triple, /*FromAs*/ false);
+      if (!CPU.empty()) {
+        CmdArgs.push_back("-target-cpu");
+        CmdArgs.push_back(Args.MakeArgString(CPU));
+      }
+    }
 
     // Render target options.
     TC.addClangTargetOptions(Args, CmdArgs, JA.getOffloadingDeviceKind());


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