https://github.com/yxsamliu created 
https://github.com/llvm/llvm-project/pull/75357

Make changes to clang driver and HIPAMD to allow compile HIP programs to SPIRV 
with HIPAMD toolchain.

>From 953685cdefdb12d5e477b107e88a1c3389eb2bb5 Mon Sep 17 00:00:00 2001
From: "Yaxun (Sam) Liu" <yaxun....@amd.com>
Date: Wed, 13 Dec 2023 11:30:13 -0500
Subject: [PATCH] Add SPIRV support to HIPAMD toolchain

Make changes to clang driver and HIPAMD to allow compile
HIP programs to SPIRV with HIPAMD toolchain.
---
 clang/docs/HIPSupport.rst                  | 28 ++++++++++++++++++++++
 clang/lib/Basic/TargetID.cpp               |  5 +++-
 clang/lib/Driver/Driver.cpp                |  3 ++-
 clang/lib/Driver/ToolChain.cpp             |  4 ++++
 clang/lib/Driver/ToolChains/AMDGPU.cpp     |  5 ++--
 clang/lib/Driver/ToolChains/HIPAMD.cpp     |  8 +++++++
 clang/test/Driver/hip-phases.hip           | 16 +++++++++----
 clang/test/Driver/hip-toolchain-no-rdc.hip | 17 +++++++++++++
 8 files changed, 77 insertions(+), 9 deletions(-)

diff --git a/clang/docs/HIPSupport.rst b/clang/docs/HIPSupport.rst
index 84cee45e83ba3c..803dd5ab2b8545 100644
--- a/clang/docs/HIPSupport.rst
+++ b/clang/docs/HIPSupport.rst
@@ -266,3 +266,31 @@ Example Usage
       Base* basePtr = &obj;
       basePtr->virtualFunction(); // Allowed since obj is constructed in 
device code
    }
+
+SPIRV Support on HIPAMD ToolChain
+=================================
+
+SPIRV is a target-neutral device executable format. The support for SPIRV in 
the ROCm and HIPAMD toolchain is under active development.
+
+Compilation Process
+-------------------
+
+When compiling HIP programs with the intent of utilizing SPIRV, the process 
diverges from the traditional compilation flow:
+
+Using ``--offload-arch=generic``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- **Target Triple**: The ``--offload-arch=generic`` flag instructs the 
compiler to use the target triple ``spirv64-unknown-unknown``. This approach 
does not generate ISA (Instruction Set Architecture) for a specific GPU 
architecture.
+
+- **LLVM IR Translation**: The program is compiled to LLVM Intermediate 
Representation (IR), which is subsequently translated into SPIRV.
+
+- **Clang Offload Bundler**: The resulting SPIRV is embedded in the Clang 
offload bundler with the bundle ID ``hipv4-hip-amdgcn-amd-amdhsa-generic``.
+
+Mixed with Normal ``--offload-arch``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- **ISA Generation**: Alongside SPIRV, the compiler can also generate ISA for 
specific GPU architectures when normal ``--offload-arch`` options are used.
+
+- **Runtime Behavior**: The HIP runtime prioritizes the use of ISA for a 
specific GPU if available. In its absence, and if SPIRV is available, the 
runtime will JIT (Just-In-Time) compile SPIRV into ISA.
+
+This approach allows for greater flexibility and portability in HIP 
programming, particularly in environments where the specific GPU architecture 
may vary or be unknown at compile time. The ability to mix SPIRV with specific 
ISA generation also provides a balanced solution for optimizing performance 
while maintaining portability.
diff --git a/clang/lib/Basic/TargetID.cpp b/clang/lib/Basic/TargetID.cpp
index 3c06d9bad1dc0d..06c8830de57be8 100644
--- a/clang/lib/Basic/TargetID.cpp
+++ b/clang/lib/Basic/TargetID.cpp
@@ -46,8 +46,11 @@ getAllPossibleTargetIDFeatures(const llvm::Triple &T,
 /// Returns canonical processor name or empty string if \p Processor is 
invalid.
 static llvm::StringRef getCanonicalProcessorName(const llvm::Triple &T,
                                                  llvm::StringRef Processor) {
-  if (T.isAMDGPU())
+  if (T.isAMDGPU()) {
+    if (Processor == "generic")
+      return Processor;
     return llvm::AMDGPU::getCanonicalArchName(T, Processor);
+  }
   return Processor;
 }
 
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index e241706b9082ee..538820246cb3ca 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -3438,7 +3438,8 @@ class OffloadingActionBuilder final {
             // compiler phases, including backend and assemble phases.
             ActionList AL;
             Action *BackendAction = nullptr;
-            if (ToolChains.front()->getTriple().isSPIRV()) {
+            if (ToolChains.front()->getTriple().isSPIRV() ||
+                StringRef(GpuArchList[I]) == "generic") {
               // Emit LLVM bitcode for SPIR-V targets. SPIR-V device tool chain
               // (HIPSPVToolChain) runs post-link LLVM IR passes.
               types::ID Output = Args.hasArg(options::OPT_S)
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index ab19166f18c2dc..6613a843c4ad3a 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -1008,6 +1008,10 @@ std::string ToolChain::ComputeLLVMTriple(const ArgList 
&Args,
     tools::arm::setFloatABIInTriple(getDriver(), Args, Triple);
     return Triple.getTriple();
   }
+  case llvm::Triple::amdgcn:
+    if (Args.getLastArgValue(options::OPT_mcpu_EQ) == "generic")
+      return "spirv64-unknown-unknown";
+    return getTripleString();
   }
 }
 
diff --git a/clang/lib/Driver/ToolChains/AMDGPU.cpp 
b/clang/lib/Driver/ToolChains/AMDGPU.cpp
index cad206ea4df1bc..5e83136d402f88 100644
--- a/clang/lib/Driver/ToolChains/AMDGPU.cpp
+++ b/clang/lib/Driver/ToolChains/AMDGPU.cpp
@@ -930,7 +930,7 @@ bool RocmInstallationDetector::checkCommonBitcodeLibs(
     D.Diag(diag::err_drv_no_rocm_device_lib) << 0;
     return false;
   }
-  if (LibDeviceFile.empty()) {
+  if (!GPUArch.empty() && LibDeviceFile.empty()) {
     D.Diag(diag::err_drv_no_rocm_device_lib) << 1 << GPUArch;
     return false;
   }
@@ -958,7 +958,8 @@ RocmInstallationDetector::getCommonBitcodeLibs(
   AddBCLib(getFiniteOnlyPath(FiniteOnly || FastRelaxedMath));
   AddBCLib(getCorrectlyRoundedSqrtPath(CorrectSqrt));
   AddBCLib(getWavefrontSize64Path(Wave64));
-  AddBCLib(LibDeviceFile);
+  if (!LibDeviceFile.empty())
+    AddBCLib(LibDeviceFile);
   auto ABIVerPath = getABIVersionPath(ABIVer);
   if (!ABIVerPath.empty())
     AddBCLib(ABIVerPath);
diff --git a/clang/lib/Driver/ToolChains/HIPAMD.cpp 
b/clang/lib/Driver/ToolChains/HIPAMD.cpp
index ccb36a6c846c80..95c820715a7622 100644
--- a/clang/lib/Driver/ToolChains/HIPAMD.cpp
+++ b/clang/lib/Driver/ToolChains/HIPAMD.cpp
@@ -10,6 +10,7 @@
 #include "AMDGPU.h"
 #include "CommonArgs.h"
 #include "HIPUtility.h"
+#include "SPIRV.h"
 #include "clang/Basic/Cuda.h"
 #include "clang/Basic/TargetID.h"
 #include "clang/Driver/Compilation.h"
@@ -209,6 +210,13 @@ void AMDGCN::Linker::ConstructJob(Compilation &C, const 
JobAction &JA,
   if (JA.getType() == types::TY_LLVM_BC)
     return constructLlvmLinkCommand(C, JA, Inputs, Output, Args);
 
+  if (Args.getLastArgValue(options::OPT_mcpu_EQ) == "generic") {
+    llvm::opt::ArgStringList TrArgs{"--spirv-max-version=1.1",
+                                    "--spirv-ext=+all"};
+    return SPIRV::constructTranslateCommand(C, *this, JA, Output, Inputs[0],
+                                            TrArgs);
+  }
+
   return constructLldCommand(C, JA, Inputs, Output, Args);
 }
 
diff --git a/clang/test/Driver/hip-phases.hip b/clang/test/Driver/hip-phases.hip
index e976583820ccf7..b7660652937b2e 100644
--- a/clang/test/Driver/hip-phases.hip
+++ b/clang/test/Driver/hip-phases.hip
@@ -11,10 +11,13 @@
 //
 // RUN: %clang -x hip --target=x86_64-unknown-linux-gnu -ccc-print-phases \
 // RUN: --cuda-gpu-arch=gfx803 %s 2>&1 \
-// RUN: | FileCheck -check-prefixes=BIN,NRD,OLD %s
+// RUN: | FileCheck -check-prefixes=BIN,NRD,OLD,GFX803 %s
 // RUN: %clang -x hip --target=x86_64-unknown-linux-gnu -ccc-print-phases \
 // RUN: --offload-new-driver --cuda-gpu-arch=gfx803 %s 2>&1 \
-// RUN: | FileCheck -check-prefixes=BIN,NRD,NEW %s
+// RUN: | FileCheck -check-prefixes=BIN,NRD,NEW,GFX803 %s
+// RUN: %clang -x hip --target=x86_64-unknown-linux-gnu -ccc-print-phases \
+// RUN: --offload-arch=generic %s 2>&1 \
+// RUN: | FileCheck -check-prefixes=BIN,NRD,OLD,GENERIC %s
 //
 // RUN: %clang -x hip --target=x86_64-unknown-linux-gnu -ccc-print-phases \
 // RUN: --cuda-gpu-arch=gfx803 -fgpu-rdc %s 2>&1 \
@@ -26,11 +29,14 @@
 // RDC-DAG: [[P12:[0-9]+]]: backend, {[[P2]]}, assembler, (host-[[T]])
 // RDC-DAG: [[P13:[0-9]+]]: assembler, {[[P12]]}, object, (host-[[T]])
 
-// BIN-DAG: [[P3:[0-9]+]]: input, "{{.*}}hip-phases.hip", [[T]], 
(device-[[T]], [[ARCH:gfx803]])
+// GFX803-DAG: [[P3:[0-9]+]]: input, "{{.*}}hip-phases.hip", [[T]], 
(device-[[T]], [[ARCH:gfx803]])
+// RDC-DAG: [[P3:[0-9]+]]: input, "{{.*}}hip-phases.hip", [[T]], 
(device-[[T]], [[ARCH:gfx803]])
+// GENERIC-DAG: [[P3:[0-9]+]]: input, "{{.*}}hip-phases.hip", [[T]], 
(device-[[T]], [[ARCH:generic]])
 // BIN-DAG: [[P4:[0-9]+]]: preprocessor, {[[P3]]}, [[T]]-cpp-output, 
(device-[[T]], [[ARCH]])
 // BIN-DAG: [[P5:[0-9]+]]: compiler, {[[P4]]}, ir, (device-[[T]], [[ARCH]])
-// NRD-DAG: [[P6:[0-9]+]]: backend, {[[P5]]}, assembler, (device-[[T]], 
[[ARCH]])
-// NRD-DAG: [[P7:[0-9]+]]: assembler, {[[P6]]}, object, (device-[[T]], 
[[ARCH]])
+// GFX803-DAG: [[P6:[0-9]+]]: backend, {[[P5]]}, assembler, (device-[[T]], 
[[ARCH]])
+// GFX803-DAG: [[P7:[0-9]+]]: assembler, {[[P6]]}, object, (device-[[T]], 
[[ARCH]])
+// GENERIC-DAG: [[P7:[0-9]+]]: backend, {[[P5]]}, ir, (device-[[T]], [[ARCH]])
 // RDC-DAG: [[P7:[0-9]+]]: backend, {[[P5]]}, ir, (device-[[T]], [[ARCH]])
 // BIN-DAG: [[P8:[0-9]+]]: linker, {[[P7]]}, image, (device-[[T]], [[ARCH]])
 // BIN-DAG: [[P9:[0-9]+]]: offload, "device-[[T]] 
(amdgcn-amd-amdhsa:[[ARCH]])" {[[P8]]}, image
diff --git a/clang/test/Driver/hip-toolchain-no-rdc.hip 
b/clang/test/Driver/hip-toolchain-no-rdc.hip
index e72df739b64b1b..dbd65f21f61192 100644
--- a/clang/test/Driver/hip-toolchain-no-rdc.hip
+++ b/clang/test/Driver/hip-toolchain-no-rdc.hip
@@ -39,6 +39,11 @@
 // RUN:   %t/a.o %t/b.o \
 // RUN: 2>&1 | FileCheck -check-prefixes=LKONLY %s
 
+// RUN: %clang -### --target=x86_64-linux-gnu \
+// RUN:   --offload-arch=generic --offload-arch=gfx900 \
+// RUN:   %s -nogpuinc -nogpulib \
+// RUN: 2>&1 | FileCheck -check-prefixes=GENERIC %s
+
 //
 // Compile device code in a.cu to code object for gfx803.
 //
@@ -180,3 +185,15 @@
 // LKONLY-NOT: {{".*/llc"}}
 // LKONLY: [[LD:".*ld.*"]] {{.*}} "{{.*/a.o}}" "{{.*/b.o}}"
 // LKONLY-NOT: "-T" "{{.*}}.lk"
+
+//
+// Check mixed SPIRV and GPU arch.
+//
+
+// GENERIC: "-cc1" "-triple" "spirv64-unknown-unknown" {{.*}}"-emit-llvm-bc" 
{{.*}} "-o" "[[GEN_BC:.*bc]]"
+// GENERIC: {{".*llvm-spirv"}} "--spirv-max-version=1.1" "--spirv-ext=+all" 
"[[GEN_BC]]" "-o" "[[GEN_SPV:.*out]]"
+// GENERIC: "-cc1" "-triple" "amdgcn-amd-amdhsa" {{.*}}"-emit-obj" 
{{.*}}"-target-cpu" "gfx900"{{.*}} "-o" "[[GFX900_OBJ:.*o]]"
+// GENERIC: {{".*lld"}} {{.*}}"-plugin-opt=mcpu=gfx900" {{.*}} "-o" 
"[[GFX900_CO:.*out]]" {{.*}}"[[GFX900_OBJ]]"
+// GENERIC: {{".*clang-offload-bundler"}} "-type=o"
+// GENERIC-SAME: 
"-targets={{.*}}hipv4-amdgcn-amd-amdhsa--generic,hipv4-amdgcn-amd-amdhsa--gfx900"
+// GENERIC-SAME: "-input=[[GEN_SPV]]" "-input=[[GFX900_CO]]"

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