[PATCH] D135305: [Clang] Fix using LTO with the new driver in RDC-mode

[Joseph Huber via Phabricator via cfe-commits]

jhuber6 created this revision.
jhuber6 added reviewers: jdoerfert, JonChesterfield, tra, yaxunl.
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Herald added a project: clang.

The new driver supports LTO for RDC-mode compilations. However, this was
not correctly handled for non-LTO compilations. HIP can handle this as
it is fed to `lld` which will perform the LTO itself. CUDA however would
require every work which is wholly useless in non-RDC mode so it should
report an error.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D135305

Files:
  clang/lib/Driver/Driver.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/test/Driver/cuda-bindings.cu
  clang/test/Driver/hip-binding.hip


Index: clang/test/Driver/hip-binding.hip
===================================================================
--- clang/test/Driver/hip-binding.hip
+++ clang/test/Driver/hip-binding.hip
@@ -79,3 +79,24 @@
 // SYNTAX-ONLY: "-cc1" "-triple" "amdgcn-amd-amdhsa"{{.*}}"-fsyntax-only"
 // SYNTAX-ONLY: "-cc1" "-triple" "amdgcn-amd-amdhsa"{{.*}}"-fsyntax-only"
 // SYNTAX-ONLY: "-cc1" "-triple" "x86_64-unknown-linux-gnu"{{.*}}"-fsyntax-only"
+
+//
+// Test the bindings using the new driver in LTO-mode.
+//
+// RUN: %clang -### --target=x86_64-linux-gnu --offload-new-driver -ccc-print-bindings \
+// RUN:        --offload-arch=gfx90a --offload-arch=gfx908 -foffload-lto -fgpu-rdc -c %s 2>&1 \
+// RUN: | FileCheck -check-prefix=LTO %s
+//      LTO: # "amdgcn-amd-amdhsa" - "clang", inputs: ["[[INPUT:.+]]"], output: "[[LTO_908:.+]]"
+// LTO-NEXT: # "amdgcn-amd-amdhsa" - "clang", inputs: ["[[INPUT]]"], output: "[[LTO_90A:.+]]"
+
+//
+// Check to ensure that we can use '-foffload' when not operating in RDC-mode.
+//
+// RUN: %clang -### --target=x86_64-linux-gnu -fno-gpu-rdc --offload-new-driver -ccc-print-bindings \
+// RUN:        -foffload-lto --offload-arch=gfx90a --offload-arch=gfx908 -c %s 2>&1 \
+// RUN: | FileCheck -check-prefix=LTO-NO-RDC %s
+//      LTO-NO-RDC: # "amdgcn-amd-amdhsa" - "clang", inputs: ["[[INPUT:.+]]"], output: "[[LTO_908:.+]]"
+// LTO-NO-RDC-NEXT: # "amdgcn-amd-amdhsa" - "AMDGCN::Linker", inputs: ["[[LTO_908]]"], output: "[[OBJ_908:.+]]"
+// LTO-NO-RDC-NEXT: # "amdgcn-amd-amdhsa" - "clang", inputs: ["[[INPUT]]"], output: "[[LTO_90A:.+]]"
+// LTO-NO-RDC-NEXT: # "amdgcn-amd-amdhsa" - "AMDGCN::Linker", inputs: ["[[LTO_90A]]"], output: "[[OBJ_90A:.+]]"
+// LTO-NO-RDC-NEXT: # "amdgcn-amd-amdhsa" - "AMDGCN::Linker", inputs: ["[[OBJ_908]]", "[[OBJ_90A]]"], output: "[[HIPFB:.+]]"
Index: clang/test/Driver/cuda-bindings.cu
===================================================================
--- clang/test/Driver/cuda-bindings.cu
+++ clang/test/Driver/cuda-bindings.cu
@@ -234,3 +234,20 @@
 // SAVE-TEMPS: "-cc1" "-triple" "nvptx64-nvidia-cuda"{{.*}}"-target-cpu" "sm_52"
 // SAVE-TEMPS: "-cc1" "-triple" "nvptx64-nvidia-cuda"{{.*}}"-target-cpu" "sm_70"
 // SAVE-TEMPS: "-cc1" "-triple" "powerpc64le-ibm-linux-gnu"
+
+//
+// Test the bindings using the new driver in LTO-mode.
+//
+// RUN: %clang -### -target powerpc64le-ibm-linux-gnu --offload-new-driver -ccc-print-bindings \
+// RUN:        --offload-arch=sm_70 --offload-arch=sm_52 -foffload-lto -fgpu-rdc -c %s 2>&1 \
+// RUN: | FileCheck -check-prefix=LTO %s
+//      LTO: # "nvptx64-nvidia-cuda" - "clang", inputs: ["[[INPUT:.+]]"], output: "[[LTO_52:.+]]"
+// LTO-NEXT: # "nvptx64-nvidia-cuda" - "clang", inputs: ["[[INPUT]]"], output: "[[LTO_70:.+]]"
+
+//
+// Check to ensure that we cannot use '-foffload' when not operating in RDC-mode.
+//
+// RUN: %clang -### -target powerpc64le-ibm-linux-gnu -fno-gpu-rdc --offload-new-driver \
+// RUN:        -foffload-lto --offload-arch=sm_70 --offload-arch=sm_52 -c %s 2>&1 \
+// RUN: | FileCheck -check-prefix=LTO-NO-RDC %s
+// LTO-NO-RDC: error: unsupported option '-foffload-lto' for language mode '-fno-gpu-rdc'
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -4842,7 +4842,6 @@
       CmdArgs.push_back("-emit-llvm-uselists");
 
     if (IsUsingLTO) {
-      // Only AMDGPU supports device-side LTO.
       if (IsDeviceOffloadAction && !JA.isDeviceOffloading(Action::OFK_OpenMP) &&
           !Args.hasFlag(options::OPT_offload_new_driver,
                         options::OPT_no_offload_new_driver, false) &&
@@ -4852,6 +4851,12 @@
                                options::OPT_foffload_lto_EQ)
                    ->getAsString(Args)
             << Triple.getTriple();
+      } else if (Triple.isNVPTX() && !IsRDCMode) {
+        D.Diag(diag::err_drv_unsupported_opt_for_language_mode)
+            << Args.getLastArg(options::OPT_foffload_lto,
+                               options::OPT_foffload_lto_EQ)
+                   ->getAsString(Args)
+            << "-fno-gpu-rdc";
       } else {
         assert(LTOMode == LTOK_Full || LTOMode == LTOK_Thin);
         CmdArgs.push_back(Args.MakeArgString(
Index: clang/lib/Driver/Driver.cpp
===================================================================
--- clang/lib/Driver/Driver.cpp
+++ clang/lib/Driver/Driver.cpp
@@ -4375,7 +4375,9 @@
 
     // Compiling HIP in non-RDC mode requires linking each action individually.
     for (Action *&A : DeviceActions) {
-      if (A->getType() != types::TY_Object || Kind != Action::OFK_HIP ||
+      if ((A->getType() != types::TY_Object &&
+           A->getType() != types::TY_LTO_BC) ||
+          Kind != Action::OFK_HIP ||
           Args.hasFlag(options::OPT_fgpu_rdc, options::OPT_fno_gpu_rdc, false))
         continue;
       ActionList LinkerInput = {A};


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