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clang-p2996/clang/lib/Driver/ToolChains/AMDGPUOpenMP.cpp
Joseph Huber 8477a0d769 [OpenMP] Allow compiling multiple target architectures with OpenMP 
This patch adds support for OpenMP to use the `--offload-arch` and
`--no-offload-arch` options. Traditionally, OpenMP has only supported
compiling for a single architecture via the `-Xopenmp-target` option.
Now we can pass in a bound architecture and use that if given, otherwise
we default to the value of the `-march` option as before.

Note that this only applies the basic support, the OpenMP target runtime
does not yet know how to choose between multiple architectures.
Additionally other parts of the offloading toolchain (e.g. LTO) require
the `-march` option, these should be worked out later.

Reviewed By: tra

Differential Revision: https://reviews.llvm.org/D124721
2022-05-06 16:57:16 -04:00

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//===- AMDGPUOpenMP.cpp - AMDGPUOpenMP ToolChain Implementation -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "AMDGPUOpenMP.h"
#include "AMDGPU.h"
#include "CommonArgs.h"
#include "ToolChains/ROCm.h"
#include "clang/Basic/DiagnosticDriver.h"
#include "clang/Driver/Compilation.h"
#include "clang/Driver/Driver.h"
#include "clang/Driver/DriverDiagnostic.h"
#include "clang/Driver/InputInfo.h"
#include "clang/Driver/Options.h"
#include "clang/Driver/Tool.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FormatAdapters.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/Path.h"
using namespace clang::driver;
using namespace clang::driver::toolchains;
using namespace clang::driver::tools;
using namespace clang;
using namespace llvm::opt;
namespace {
static const char *getOutputFileName(Compilation &C, StringRef Base,
const char *Postfix,
const char *Extension) {
const char *OutputFileName;
if (C.getDriver().isSaveTempsEnabled()) {
OutputFileName =
C.getArgs().MakeArgString(Base.str() + Postfix + "." + Extension);
} else {
std::string TmpName =
C.getDriver().GetTemporaryPath(Base.str() + Postfix, Extension);
OutputFileName = C.addTempFile(C.getArgs().MakeArgString(TmpName));
}
return OutputFileName;
}
static void addLLCOptArg(const llvm::opt::ArgList &Args,
llvm::opt::ArgStringList &CmdArgs) {
if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
StringRef OOpt = "0";
if (A->getOption().matches(options::OPT_O4) ||
A->getOption().matches(options::OPT_Ofast))
OOpt = "3";
else if (A->getOption().matches(options::OPT_O0))
OOpt = "0";
else if (A->getOption().matches(options::OPT_O)) {
// Clang and opt support -Os/-Oz; llc only supports -O0, -O1, -O2 and -O3
// so we map -Os/-Oz to -O2.
// Only clang supports -Og, and maps it to -O1.
// We map anything else to -O2.
OOpt = llvm::StringSwitch<const char *>(A->getValue())
.Case("1", "1")
.Case("2", "2")
.Case("3", "3")
.Case("s", "2")
.Case("z", "2")
.Case("g", "1")
.Default("0");
}
CmdArgs.push_back(Args.MakeArgString("-O" + OOpt));
}
}
static bool checkSystemForAMDGPU(const ArgList &Args, const AMDGPUToolChain &TC,
std::string &GPUArch) {
if (auto Err = TC.getSystemGPUArch(Args, GPUArch)) {
std::string ErrMsg =
llvm::formatv("{0}", llvm::fmt_consume(std::move(Err)));
TC.getDriver().Diag(diag::err_drv_undetermined_amdgpu_arch) << ErrMsg;
return false;
}
return true;
}
} // namespace
const char *AMDGCN::OpenMPLinker::constructLLVMLinkCommand(
const toolchains::AMDGPUOpenMPToolChain &AMDGPUOpenMPTC, Compilation &C,
const JobAction &JA, const InputInfoList &Inputs, const ArgList &Args,
StringRef SubArchName, StringRef OutputFilePrefix) const {
ArgStringList CmdArgs;
for (const auto &II : Inputs)
if (II.isFilename())
CmdArgs.push_back(II.getFilename());
bool HasLibm = false;
if (Args.hasArg(options::OPT_l)) {
auto Lm = Args.getAllArgValues(options::OPT_l);
for (auto &Lib : Lm) {
if (Lib == "m") {
HasLibm = true;
break;
}
}
if (HasLibm) {
// This is not certain to work. The device libs added here, and passed to
// llvm-link, are missing attributes that they expect to be inserted when
// passed to mlink-builtin-bitcode. The amdgpu backend does not generate
// conservatively correct code when attributes are missing, so this may
// be the root cause of miscompilations. Passing via mlink-builtin-bitcode
// ultimately hits CodeGenModule::addDefaultFunctionDefinitionAttributes
// on each function, see D28538 for context.
// Potential workarounds:
// - unconditionally link all of the device libs to every translation
// unit in clang via mlink-builtin-bitcode
// - build a libm bitcode file as part of the DeviceRTL and explictly
// mlink-builtin-bitcode the rocm device libs components at build time
// - drop this llvm-link fork in favour or some calls into LLVM, chosen
// to do basically the same work as llvm-link but with that call first
// - write an opt pass that sets that on every function it sees and pipe
// the device-libs bitcode through that on the way to this llvm-link
SmallVector<std::string, 12> BCLibs =
AMDGPUOpenMPTC.getCommonDeviceLibNames(Args, SubArchName.str());
llvm::for_each(BCLibs, [&](StringRef BCFile) {
CmdArgs.push_back(Args.MakeArgString(BCFile));
});
}
}
AddStaticDeviceLibsLinking(C, *this, JA, Inputs, Args, CmdArgs, "amdgcn",
SubArchName, /*isBitCodeSDL=*/true,
/*postClangLink=*/false);
// Add an intermediate output file.
CmdArgs.push_back("-o");
const char *OutputFileName =
getOutputFileName(C, OutputFilePrefix, "-linked", "bc");
CmdArgs.push_back(OutputFileName);
const char *Exec =
Args.MakeArgString(getToolChain().GetProgramPath("llvm-link"));
C.addCommand(std::make_unique<Command>(
JA, *this, ResponseFileSupport::AtFileCurCP(), Exec, CmdArgs, Inputs,
InputInfo(&JA, Args.MakeArgString(OutputFileName))));
// If we linked in libm definitions late we run another round of optimizations
// to inline the definitions and fold what is foldable.
if (HasLibm) {
ArgStringList OptCmdArgs;
const char *OptOutputFileName =
getOutputFileName(C, OutputFilePrefix, "-linked-opt", "bc");
addLLCOptArg(Args, OptCmdArgs);
OptCmdArgs.push_back(OutputFileName);
OptCmdArgs.push_back("-o");
OptCmdArgs.push_back(OptOutputFileName);
const char *OptExec =
Args.MakeArgString(getToolChain().GetProgramPath("opt"));
C.addCommand(std::make_unique<Command>(
JA, *this, ResponseFileSupport::AtFileCurCP(), OptExec, OptCmdArgs,
InputInfo(&JA, Args.MakeArgString(OutputFileName)),
InputInfo(&JA, Args.MakeArgString(OptOutputFileName))));
OutputFileName = OptOutputFileName;
}
return OutputFileName;
}
const char *AMDGCN::OpenMPLinker::constructLlcCommand(
Compilation &C, const JobAction &JA, const InputInfoList &Inputs,
const llvm::opt::ArgList &Args, llvm::StringRef SubArchName,
llvm::StringRef OutputFilePrefix, const char *InputFileName,
bool OutputIsAsm) const {
// Construct llc command.
ArgStringList LlcArgs;
// The input to llc is the output from opt.
LlcArgs.push_back(InputFileName);
// Pass optimization arg to llc.
addLLCOptArg(Args, LlcArgs);
LlcArgs.push_back("-mtriple=amdgcn-amd-amdhsa");
LlcArgs.push_back(Args.MakeArgString("-mcpu=" + SubArchName));
LlcArgs.push_back(
Args.MakeArgString(Twine("-filetype=") + (OutputIsAsm ? "asm" : "obj")));
for (const Arg *A : Args.filtered(options::OPT_mllvm)) {
LlcArgs.push_back(A->getValue(0));
}
// Add output filename
LlcArgs.push_back("-o");
const char *LlcOutputFile =
getOutputFileName(C, OutputFilePrefix, "", OutputIsAsm ? "s" : "o");
LlcArgs.push_back(LlcOutputFile);
const char *Llc = Args.MakeArgString(getToolChain().GetProgramPath("llc"));
C.addCommand(std::make_unique<Command>(
JA, *this, ResponseFileSupport::AtFileCurCP(), Llc, LlcArgs, Inputs,
InputInfo(&JA, Args.MakeArgString(LlcOutputFile))));
return LlcOutputFile;
}
void AMDGCN::OpenMPLinker::constructLldCommand(
Compilation &C, const JobAction &JA, const InputInfoList &Inputs,
const InputInfo &Output, const llvm::opt::ArgList &Args,
const char *InputFileName) const {
// Construct lld command.
// The output from ld.lld is an HSA code object file.
ArgStringList LldArgs{"-flavor", "gnu", "--no-undefined",
"-shared", "-o", Output.getFilename(),
InputFileName};
const char *Lld = Args.MakeArgString(getToolChain().GetProgramPath("lld"));
C.addCommand(std::make_unique<Command>(
JA, *this, ResponseFileSupport::AtFileCurCP(), Lld, LldArgs, Inputs,
InputInfo(&JA, Args.MakeArgString(Output.getFilename()))));
}
// For amdgcn the inputs of the linker job are device bitcode and output is
// object file. It calls llvm-link, opt, llc, then lld steps.
void AMDGCN::OpenMPLinker::ConstructJob(Compilation &C, const JobAction &JA,
const InputInfo &Output,
const InputInfoList &Inputs,
const ArgList &Args,
const char *LinkingOutput) const {
const ToolChain &TC = getToolChain();
assert(getToolChain().getTriple().isAMDGCN() && "Unsupported target");
const toolchains::AMDGPUOpenMPToolChain &AMDGPUOpenMPTC =
static_cast<const toolchains::AMDGPUOpenMPToolChain &>(TC);
std::string GPUArch = Args.getLastArgValue(options::OPT_march_EQ).str();
if (GPUArch.empty()) {
if (!checkSystemForAMDGPU(Args, AMDGPUOpenMPTC, GPUArch))
return;
}
// Prefix for temporary file name.
std::string Prefix;
for (const auto &II : Inputs)
if (II.isFilename())
Prefix = llvm::sys::path::stem(II.getFilename()).str() + "-" + GPUArch;
assert(Prefix.length() && "no linker inputs are files ");
// Each command outputs different files.
const char *LLVMLinkCommand = constructLLVMLinkCommand(
AMDGPUOpenMPTC, C, JA, Inputs, Args, GPUArch, Prefix);
// Produce readable assembly if save-temps is enabled.
if (C.getDriver().isSaveTempsEnabled())
constructLlcCommand(C, JA, Inputs, Args, GPUArch, Prefix, LLVMLinkCommand,
/*OutputIsAsm=*/true);
const char *LlcCommand = constructLlcCommand(C, JA, Inputs, Args, GPUArch,
Prefix, LLVMLinkCommand);
constructLldCommand(C, JA, Inputs, Output, Args, LlcCommand);
}
AMDGPUOpenMPToolChain::AMDGPUOpenMPToolChain(const Driver &D,
const llvm::Triple &Triple,
const ToolChain &HostTC,
const ArgList &Args)
: ROCMToolChain(D, Triple, Args), HostTC(HostTC) {
// Lookup binaries into the driver directory, this is used to
// discover the clang-offload-bundler executable.
getProgramPaths().push_back(getDriver().Dir);
}
void AMDGPUOpenMPToolChain::addClangTargetOptions(
const llvm::opt::ArgList &DriverArgs, llvm::opt::ArgStringList &CC1Args,
Action::OffloadKind DeviceOffloadingKind) const {
HostTC.addClangTargetOptions(DriverArgs, CC1Args, DeviceOffloadingKind);
std::string GPUArch = DriverArgs.getLastArgValue(options::OPT_march_EQ).str();
if (GPUArch.empty()) {
if (!checkSystemForAMDGPU(DriverArgs, *this, GPUArch))
return;
}
assert(DeviceOffloadingKind == Action::OFK_OpenMP &&
"Only OpenMP offloading kinds are supported.");
CC1Args.push_back("-target-cpu");
CC1Args.push_back(DriverArgs.MakeArgStringRef(GPUArch));
CC1Args.push_back("-fcuda-is-device");
if (DriverArgs.hasArg(options::OPT_nogpulib))
return;
// Link the bitcode library late if we're using device LTO.
if (getDriver().isUsingLTO(/* IsOffload */ true))
return;
addOpenMPDeviceRTL(getDriver(), DriverArgs, CC1Args, GPUArch, getTriple());
}
llvm::opt::DerivedArgList *AMDGPUOpenMPToolChain::TranslateArgs(
const llvm::opt::DerivedArgList &Args, StringRef BoundArch,
Action::OffloadKind DeviceOffloadKind) const {
DerivedArgList *DAL =
HostTC.TranslateArgs(Args, BoundArch, DeviceOffloadKind);
if (!DAL)
DAL = new DerivedArgList(Args.getBaseArgs());
const OptTable &Opts = getDriver().getOpts();
if (DeviceOffloadKind == Action::OFK_OpenMP) {
for (Arg *A : Args)
if (!llvm::is_contained(*DAL, A))
DAL->append(A);
if (!DAL->hasArg(options::OPT_march_EQ)) {
std::string Arch = BoundArch.str();
if (BoundArch.empty())
checkSystemForAMDGPU(Args, *this, Arch);
DAL->AddJoinedArg(nullptr, Opts.getOption(options::OPT_march_EQ), Arch);
}
return DAL;
}
for (Arg *A : Args) {
DAL->append(A);
}
if (!BoundArch.empty()) {
DAL->eraseArg(options::OPT_march_EQ);
DAL->AddJoinedArg(nullptr, Opts.getOption(options::OPT_march_EQ),
BoundArch);
}
return DAL;
}
Tool *AMDGPUOpenMPToolChain::buildLinker() const {
assert(getTriple().isAMDGCN());
return new tools::AMDGCN::OpenMPLinker(*this);
}
void AMDGPUOpenMPToolChain::addClangWarningOptions(
ArgStringList &CC1Args) const {
HostTC.addClangWarningOptions(CC1Args);
}
ToolChain::CXXStdlibType
AMDGPUOpenMPToolChain::GetCXXStdlibType(const ArgList &Args) const {
return HostTC.GetCXXStdlibType(Args);
}
void AMDGPUOpenMPToolChain::AddClangSystemIncludeArgs(
const ArgList &DriverArgs, ArgStringList &CC1Args) const {
HostTC.AddClangSystemIncludeArgs(DriverArgs, CC1Args);
}
void AMDGPUOpenMPToolChain::AddIAMCUIncludeArgs(const ArgList &Args,
ArgStringList &CC1Args) const {
HostTC.AddIAMCUIncludeArgs(Args, CC1Args);
}
SanitizerMask AMDGPUOpenMPToolChain::getSupportedSanitizers() const {
// The AMDGPUOpenMPToolChain only supports sanitizers in the sense that it
// allows sanitizer arguments on the command line if they are supported by the
// host toolchain. The AMDGPUOpenMPToolChain will actually ignore any command
// line arguments for any of these "supported" sanitizers. That means that no
// sanitization of device code is actually supported at this time.
//
// This behavior is necessary because the host and device toolchains
// invocations often share the command line, so the device toolchain must
// tolerate flags meant only for the host toolchain.
return HostTC.getSupportedSanitizers();
}
VersionTuple
AMDGPUOpenMPToolChain::computeMSVCVersion(const Driver *D,
const ArgList &Args) const {
return HostTC.computeMSVCVersion(D, Args);
}
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