[llvm] 43fd244 - Reland "[AMDGPU] Add AMDGPU-specific module splitting (#89245)"
via llvm-commits
llvm-commits at lists.llvm.org
Mon May 27 01:43:06 PDT 2024
Author: Pierre van Houtryve
Date: 2024-05-27T10:43:00+02:00
New Revision: 43fd244b3d5c08bfd3aad0913b0fe84339842f4e
URL: https://github.com/llvm/llvm-project/commit/43fd244b3d5c08bfd3aad0913b0fe84339842f4e
DIFF: https://github.com/llvm/llvm-project/commit/43fd244b3d5c08bfd3aad0913b0fe84339842f4e.diff
LOG: Reland "[AMDGPU] Add AMDGPU-specific module splitting (#89245)"
(with fix for ubsan)
This enables the --lto-partitions option to work more consistently.
This module splitting logic is fully aware of AMDGPU modules and their
specificities and takes advantage of
them to split modules in a way that avoids compilation issue (such as
resource usage being incorrectly represented).
This also includes a logging system that's more elaborate than just
LLVM_DEBUG which allows
printing logs to uniquely named files, and optionally with all value
names hidden so they can be safely shared without leaking informatiton
about the source. Logs can also be enabled through an environment
variable, which avoids the sometimes complicated process of passing a
-mllvm option all the way from clang driver to the offload linker that
handles full LTO codegen.
Added:
llvm/lib/Target/AMDGPU/AMDGPUSplitModule.cpp
llvm/lib/Target/AMDGPU/AMDGPUSplitModule.h
llvm/test/tools/llvm-split/AMDGPU/address-taken-externalize-with-call.ll
llvm/test/tools/llvm-split/AMDGPU/address-taken-externalize.ll
llvm/test/tools/llvm-split/AMDGPU/debug-name-hiding.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-alias-dependencies.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-cost-ranking.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-dependencies.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-duplication.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-external.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-indirect.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-overridable.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-global-variables-noexternal.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-global-variables.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-load-balancing.ll
llvm/test/tools/llvm-split/AMDGPU/kernels-no-dependencies.ll
llvm/test/tools/llvm-split/AMDGPU/large-kernels-merging.ll
llvm/test/tools/llvm-split/AMDGPU/lit.local.cfg
Modified:
llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
llvm/lib/Target/AMDGPU/CMakeLists.txt
Removed:
################################################################################
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUSplitModule.cpp b/llvm/lib/Target/AMDGPU/AMDGPUSplitModule.cpp
new file mode 100644
index 00000000000000..dab773f28752d2
--- /dev/null
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSplitModule.cpp
@@ -0,0 +1,744 @@
+//===- AMDGPUSplitModule.cpp ----------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file Implements a module splitting algorithm designed to support the
+/// FullLTO --lto-partitions option for parallel codegen. This is completely
+///
diff erent from the common SplitModule pass, as this system is designed with
+/// AMDGPU in mind.
+///
+/// The basic idea of this module splitting implementation is the same as
+/// SplitModule: load-balance the module's functions across a set of N
+/// partitions to allow parallel codegen. However, it does it very
+///
diff erently than the target-agnostic variant:
+/// - Kernels are used as the module's "roots".
+/// They're known entry points on AMDGPU, and everything else is often
+/// internal only.
+/// - Each kernel has a set of dependencies, and when a kernel and its
+/// dependencies is considered "big", we try to put it in a partition where
+/// most dependencies are already imported, to avoid duplicating large
+/// amounts of code.
+/// - There's special care for indirect calls in order to ensure
+/// AMDGPUResourceUsageAnalysis can work correctly.
+///
+/// This file also includes a more elaborate logging system to enable
+/// users to easily generate logs that (if desired) do not include any value
+/// names, in order to not leak information about the source file.
+/// Such logs are very helpful to understand and fix potential issues with
+/// module splitting.
+
+#include "AMDGPUSplitModule.h"
+#include "AMDGPUTargetMachine.h"
+#include "Utils/AMDGPUBaseInfo.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Analysis/CallGraph.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/User.h"
+#include "llvm/IR/Value.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Process.h"
+#include "llvm/Support/SHA256.h"
+#include "llvm/Support/Threading.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+#include <algorithm>
+#include <cassert>
+#include <iterator>
+#include <memory>
+#include <utility>
+#include <vector>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "amdgpu-split-module"
+
+namespace {
+
+static cl::opt<float> LargeKernelFactor(
+ "amdgpu-module-splitting-large-kernel-threshold", cl::init(2.0f),
+ cl::Hidden,
+ cl::desc(
+ "consider a kernel as large and needing special treatment when it "
+ "exceeds the average cost of a partition by this factor; e;g. 2.0 "
+ "means if the kernel and its dependencies is 2 times bigger than "
+ "an average partition; 0 disables large kernels handling entirely"));
+
+static cl::opt<float> LargeKernelOverlapForMerge(
+ "amdgpu-module-splitting-large-kernel-merge-overlap", cl::init(0.8f),
+ cl::Hidden,
+ cl::desc("defines how much overlap between two large kernel's dependencies "
+ "is needed to put them in the same partition"));
+
+static cl::opt<bool> NoExternalizeGlobals(
+ "amdgpu-module-splitting-no-externalize-globals", cl::Hidden,
+ cl::desc("disables externalization of global variable with local linkage; "
+ "may cause globals to be duplicated which increases binary size"));
+
+static cl::opt<std::string>
+ LogDirOpt("amdgpu-module-splitting-log-dir", cl::Hidden,
+ cl::desc("output directory for AMDGPU module splitting logs"));
+
+static cl::opt<bool>
+ LogPrivate("amdgpu-module-splitting-log-private", cl::Hidden,
+ cl::desc("hash value names before printing them in the AMDGPU "
+ "module splitting logs"));
+
+using CostType = InstructionCost::CostType;
+using PartitionID = unsigned;
+
+static bool isEntryPoint(const Function *F) {
+ return AMDGPU::isEntryFunctionCC(F->getCallingConv());
+}
+
+static std::string getName(const Value &V) {
+ static bool HideNames;
+
+ static llvm::once_flag HideNameInitFlag;
+ llvm::call_once(HideNameInitFlag, [&]() {
+ if (LogPrivate.getNumOccurrences())
+ HideNames = LogPrivate;
+ else {
+ const auto EV = sys::Process::GetEnv("AMD_SPLIT_MODULE_LOG_PRIVATE");
+ HideNames = (EV.value_or("0") != "0");
+ }
+ });
+
+ if (!HideNames)
+ return V.getName().str();
+ return toHex(SHA256::hash(arrayRefFromStringRef(V.getName())),
+ /*LowerCase=*/true);
+}
+
+/// Main logging helper.
+///
+/// Logging can be configured by the following environment variable.
+/// AMD_SPLIT_MODULE_LOG_DIR=<filepath>
+/// If set, uses <filepath> as the directory to write logfiles to
+/// each time module splitting is used.
+/// AMD_SPLIT_MODULE_LOG_PRIVATE
+/// If set to anything other than zero, all names are hidden.
+///
+/// Both environment variables have corresponding CL options which
+/// takes priority over them.
+///
+/// Any output printed to the log files is also printed to dbgs() when -debug is
+/// used and LLVM_DEBUG is defined.
+///
+/// This approach has a small disadvantage over LLVM_DEBUG though: logging logic
+/// cannot be removed from the code (by building without debug). This probably
+/// has a small performance cost because if some computation/formatting is
+/// needed for logging purpose, it may be done everytime only to be ignored
+/// by the logger.
+///
+/// As this pass only runs once and is not doing anything computationally
+/// expensive, this is likely a reasonable trade-off.
+///
+/// If some computation should really be avoided when unused, users of the class
+/// can check whether any logging will occur by using the bool operator.
+///
+/// \code
+/// if (SML) {
+/// // Executes only if logging to a file or if -debug is available and
+/// used.
+/// }
+/// \endcode
+class SplitModuleLogger {
+public:
+ SplitModuleLogger(const Module &M) {
+ std::string LogDir = LogDirOpt;
+ if (LogDir.empty())
+ LogDir = sys::Process::GetEnv("AMD_SPLIT_MODULE_LOG_DIR").value_or("");
+
+ // No log dir specified means we don't need to log to a file.
+ // We may still log to dbgs(), though.
+ if (LogDir.empty())
+ return;
+
+ // If a log directory is specified, create a new file with a unique name in
+ // that directory.
+ int Fd;
+ SmallString<0> PathTemplate;
+ SmallString<0> RealPath;
+ sys::path::append(PathTemplate, LogDir, "Module-%%-%%-%%-%%-%%-%%-%%.txt");
+ if (auto Err =
+ sys::fs::createUniqueFile(PathTemplate.str(), Fd, RealPath)) {
+ report_fatal_error("Failed to create log file at '" + Twine(LogDir) +
+ "': " + Err.message(),
+ /*CrashDiag=*/false);
+ }
+
+ FileOS = std::make_unique<raw_fd_ostream>(Fd, /*shouldClose=*/true);
+ }
+
+ bool hasLogFile() const { return FileOS != nullptr; }
+
+ raw_ostream &logfile() {
+ assert(FileOS && "no logfile!");
+ return *FileOS;
+ }
+
+ /// \returns true if this SML will log anything either to a file or dbgs().
+ /// Can be used to avoid expensive computations that are ignored when logging
+ /// is disabled.
+ operator bool() const {
+ return hasLogFile() || (DebugFlag && isCurrentDebugType(DEBUG_TYPE));
+ }
+
+private:
+ std::unique_ptr<raw_fd_ostream> FileOS;
+};
+
+template <typename Ty>
+static SplitModuleLogger &operator<<(SplitModuleLogger &SML, const Ty &Val) {
+ static_assert(
+ !std::is_same_v<Ty, Value>,
+ "do not print values to logs directly, use handleName instead!");
+ LLVM_DEBUG(dbgs() << Val);
+ if (SML.hasLogFile())
+ SML.logfile() << Val;
+ return SML;
+}
+
+/// Calculate the cost of each function in \p M
+/// \param SML Log Helper
+/// \param TM TargetMachine instance used to retrieve TargetTransformInfo.
+/// \param M Module to analyze.
+/// \param CostMap[out] Resulting Function -> Cost map.
+/// \return The module's total cost.
+static CostType
+calculateFunctionCosts(SplitModuleLogger &SML, const AMDGPUTargetMachine &TM,
+ Module &M,
+ DenseMap<const Function *, CostType> &CostMap) {
+ CostType ModuleCost = 0;
+ CostType KernelCost = 0;
+
+ for (auto &Fn : M) {
+ if (Fn.isDeclaration())
+ continue;
+
+ CostType FnCost = 0;
+ TargetTransformInfo TTI = TM.getTargetTransformInfo(Fn);
+
+ for (const auto &BB : Fn) {
+ for (const auto &I : BB) {
+ auto Cost =
+ TTI.getInstructionCost(&I, TargetTransformInfo::TCK_CodeSize);
+ assert(Cost != InstructionCost::getMax());
+ // Assume expensive if we can't tell the cost of an instruction.
+ CostType CostVal =
+ Cost.getValue().value_or(TargetTransformInfo::TCC_Expensive);
+ assert((FnCost + CostVal) >= FnCost && "Overflow!");
+ FnCost += CostVal;
+ }
+ }
+
+ assert(FnCost != 0);
+
+ CostMap[&Fn] = FnCost;
+ assert((ModuleCost + FnCost) >= ModuleCost && "Overflow!");
+ ModuleCost += FnCost;
+
+ if (isEntryPoint(&Fn))
+ KernelCost += FnCost;
+ }
+
+ CostType FnCost = (ModuleCost - KernelCost);
+ SML << "=> Total Module Cost: " << ModuleCost << '\n'
+ << " => KernelCost: " << KernelCost << " ("
+ << format("%0.2f", (float(KernelCost) / ModuleCost) * 100) << "%)\n"
+ << " => FnsCost: " << FnCost << " ("
+ << format("%0.2f", (float(FnCost) / ModuleCost) * 100) << "%)\n";
+
+ return ModuleCost;
+}
+
+static bool canBeIndirectlyCalled(const Function &F) {
+ if (F.isDeclaration() || isEntryPoint(&F))
+ return false;
+ return !F.hasLocalLinkage() ||
+ F.hasAddressTaken(/*PutOffender=*/nullptr,
+ /*IgnoreCallbackUses=*/false,
+ /*IgnoreAssumeLikeCalls=*/true,
+ /*IgnoreLLVMUsed=*/true,
+ /*IgnoreARCAttachedCall=*/false,
+ /*IgnoreCastedDirectCall=*/true);
+}
+
+/// When a kernel or any of its callees performs an indirect call, this function
+/// takes over \ref addAllDependencies and adds all potentially callable
+/// functions to \p Fns so they can be counted as dependencies of the kernel.
+///
+/// This is needed due to how AMDGPUResourceUsageAnalysis operates: in the
+/// presence of an indirect call, the function's resource usage is the same as
+/// the most expensive function in the module.
+/// \param M The module.
+/// \param Fns[out] Resulting list of functions.
+static void addAllIndirectCallDependencies(const Module &M,
+ DenseSet<const Function *> &Fns) {
+ for (const auto &Fn : M) {
+ if (canBeIndirectlyCalled(Fn))
+ Fns.insert(&Fn);
+ }
+}
+
+/// Adds the functions that \p Fn may call to \p Fns, then recurses into each
+/// callee until all reachable functions have been gathered.
+///
+/// \param SML Log Helper
+/// \param CG Call graph for \p Fn's module.
+/// \param Fn Current function to look at.
+/// \param Fns[out] Resulting list of functions.
+/// \param HadIndirectCall[out] Set to true if an indirect call was seen at some
+/// point, either in \p Fn or in one of the function it calls. When that
+/// happens, we fall back to adding all callable functions inside \p Fn's module
+/// to \p Fns.
+static void addAllDependencies(SplitModuleLogger &SML, const CallGraph &CG,
+ const Function &Fn,
+ DenseSet<const Function *> &Fns,
+ bool &HadIndirectCall) {
+ assert(!Fn.isDeclaration());
+
+ const Module &M = *Fn.getParent();
+ SmallVector<const Function *> WorkList({&Fn});
+ while (!WorkList.empty()) {
+ const auto &CurFn = *WorkList.pop_back_val();
+ assert(!CurFn.isDeclaration());
+
+ // Scan for an indirect call. If such a call is found, we have to
+ // conservatively assume this can call all non-entrypoint functions in the
+ // module.
+
+ for (auto &CGEntry : *CG[&CurFn]) {
+ auto *CGNode = CGEntry.second;
+ auto *Callee = CGNode->getFunction();
+ if (!Callee) {
+ // Functions have an edge towards CallsExternalNode if they're external
+ // declarations, or if they do an indirect call. As we only process
+ // definitions here, we know this means the function has an indirect
+ // call. We then have to conservatively assume this can call all
+ // non-entrypoint functions in the module.
+ if (CGNode != CG.getCallsExternalNode())
+ continue; // this is another function-less node we don't care about.
+
+ SML << "Indirect call detected in " << getName(CurFn)
+ << " - treating all non-entrypoint functions as "
+ "potential dependencies\n";
+
+ // TODO: Print an ORE as well ?
+ addAllIndirectCallDependencies(M, Fns);
+ HadIndirectCall = true;
+ return;
+ }
+
+ if (Callee->isDeclaration())
+ continue;
+
+ auto [It, Inserted] = Fns.insert(Callee);
+ if (Inserted)
+ WorkList.push_back(Callee);
+ }
+ }
+}
+
+/// Contains information about a kernel and its dependencies.
+struct KernelWithDependencies {
+ KernelWithDependencies(SplitModuleLogger &SML, CallGraph &CG,
+ const DenseMap<const Function *, CostType> &FnCosts,
+ const Function *Fn)
+ : Fn(Fn) {
+ addAllDependencies(SML, CG, *Fn, Dependencies, HasIndirectCall);
+ TotalCost = FnCosts.at(Fn);
+ for (const auto *Dep : Dependencies) {
+ TotalCost += FnCosts.at(Dep);
+
+ // We cannot duplicate functions with external linkage, or functions that
+ // may be overriden at runtime.
+ HasNonDuplicatableDependecy |=
+ (Dep->hasExternalLinkage() || !Dep->isDefinitionExact());
+ }
+ }
+
+ const Function *Fn = nullptr;
+ DenseSet<const Function *> Dependencies;
+ /// Whether \p Fn or any of its \ref Dependencies contains an indirect call.
+ bool HasIndirectCall = false;
+ /// Whether any of \p Fn's dependencies cannot be duplicated.
+ bool HasNonDuplicatableDependecy = false;
+
+ CostType TotalCost = 0;
+
+ /// \returns true if this kernel and its dependencies can be considered large
+ /// according to \p Threshold.
+ bool isLarge(CostType Threshold) const {
+ return TotalCost > Threshold && !Dependencies.empty();
+ }
+};
+
+/// Calculates how much overlap there is between \p A and \p B.
+/// \return A number between 0.0 and 1.0, where 1.0 means A == B and 0.0 means A
+/// and B have no shared elements. Kernels do not count in overlap calculation.
+static float calculateOverlap(const DenseSet<const Function *> &A,
+ const DenseSet<const Function *> &B) {
+ DenseSet<const Function *> Total;
+ for (const auto *F : A) {
+ if (!isEntryPoint(F))
+ Total.insert(F);
+ }
+
+ if (Total.empty())
+ return 0.0f;
+
+ unsigned NumCommon = 0;
+ for (const auto *F : B) {
+ if (isEntryPoint(F))
+ continue;
+
+ auto [It, Inserted] = Total.insert(F);
+ if (!Inserted)
+ ++NumCommon;
+ }
+
+ return static_cast<float>(NumCommon) / Total.size();
+}
+
+/// Performs all of the partitioning work on \p M.
+/// \param SML Log Helper
+/// \param M Module to partition.
+/// \param NumParts Number of partitions to create.
+/// \param ModuleCost Total cost of all functions in \p M.
+/// \param FnCosts Map of Function -> Cost
+/// \param WorkList Kernels and their dependencies to process in order.
+/// \returns The created partitions (a vector of size \p NumParts )
+static std::vector<DenseSet<const Function *>>
+doPartitioning(SplitModuleLogger &SML, Module &M, unsigned NumParts,
+ CostType ModuleCost,
+ const DenseMap<const Function *, CostType> &FnCosts,
+ const SmallVector<KernelWithDependencies> &WorkList) {
+
+ SML << "\n--Partitioning Starts--\n";
+
+ // Calculate a "large kernel threshold". When more than one kernel's total
+ // import cost exceeds this value, we will try to merge it with other,
+ // similarly large kernels.
+ //
+ // e.g. let two kernels X and Y have a import cost of ~10% of the module, we
+ // assign X to a partition as usual, but when we get to Y, we check if it's
+ // worth also putting it in Y's partition.
+ const CostType LargeKernelThreshold =
+ LargeKernelFactor ? CostType(((ModuleCost / NumParts) * LargeKernelFactor))
+ : std::numeric_limits<CostType>::max();
+
+ std::vector<DenseSet<const Function *>> Partitions;
+ Partitions.resize(NumParts);
+
+ // Assign a partition to each kernel, and try to keep the partitions more or
+ // less balanced. We do that through a priority queue sorted in reverse, so we
+ // can always look at the partition with the least content.
+ //
+ // There are some cases where we will be deliberately unbalanced though.
+ // - Large kernels: we try to merge with existing partitions to reduce code
+ // duplication.
+ // - Kernels with indirect or external calls always go in the first partition
+ // (P0).
+ auto ComparePartitions = [](const std::pair<PartitionID, CostType> &a,
+ const std::pair<PartitionID, CostType> &b) {
+ // When two partitions have the same cost, assign to the one with the
+ // biggest ID first. This allows us to put things in P0 last, because P0 may
+ // have other stuff added later.
+ if (a.second == b.second)
+ return a.first < b.first;
+ return a.second > b.second;
+ };
+
+ // We can't use priority_queue here because we need to be able to access any
+ // element. This makes this a bit inefficient as we need to sort it again
+ // everytime we change it, but it's a very small array anyway (likely under 64
+ // partitions) so it's a cheap operation.
+ std::vector<std::pair<PartitionID, CostType>> BalancingQueue;
+ for (unsigned I = 0; I < NumParts; ++I)
+ BalancingQueue.push_back(std::make_pair(I, 0));
+
+ // Helper function to handle assigning a kernel to a partition. This takes
+ // care of updating the balancing queue.
+ const auto AssignToPartition = [&](PartitionID PID,
+ const KernelWithDependencies &KWD) {
+ auto &FnsInPart = Partitions[PID];
+ FnsInPart.insert(KWD.Fn);
+ FnsInPart.insert(KWD.Dependencies.begin(), KWD.Dependencies.end());
+
+ SML << "assign " << getName(*KWD.Fn) << " to P" << PID << "\n -> ";
+ if (!KWD.Dependencies.empty()) {
+ SML << KWD.Dependencies.size() << " dependencies added\n";
+ };
+
+ // Update the balancing queue. we scan backwards because in the common case
+ // the partition is at the end.
+ for (auto &[QueuePID, Cost] : reverse(BalancingQueue)) {
+ if (QueuePID == PID) {
+ CostType NewCost = 0;
+ for (auto *Fn : Partitions[PID])
+ NewCost += FnCosts.at(Fn);
+
+ SML << "[Updating P" << PID << " Cost]:" << Cost << " -> " << NewCost;
+ if (Cost) {
+ SML << " (" << unsigned(((float(NewCost) / Cost) - 1) * 100)
+ << "% increase)";
+ }
+ SML << '\n';
+
+ Cost = NewCost;
+ }
+ }
+
+ sort(BalancingQueue, ComparePartitions);
+ };
+
+ for (auto &CurKernel : WorkList) {
+ // When a kernel has indirect calls, it must stay in the first partition
+ // alongside every reachable non-entry function. This is a nightmare case
+ // for splitting as it severely limits what we can do.
+ if (CurKernel.HasIndirectCall) {
+ SML << "Kernel with indirect call(s): " << getName(*CurKernel.Fn)
+ << " defaulting to P0\n";
+ AssignToPartition(0, CurKernel);
+ continue;
+ }
+
+ // When a kernel has non duplicatable dependencies, we have to keep it in
+ // the first partition as well. This is a conservative approach, a
+ // finer-grained approach could keep track of which dependencies are
+ // non-duplicatable exactly and just make sure they're grouped together.
+ if (CurKernel.HasNonDuplicatableDependecy) {
+ SML << "Kernel with externally visible dependency "
+ << getName(*CurKernel.Fn) << " defaulting to P0\n";
+ AssignToPartition(0, CurKernel);
+ continue;
+ }
+
+ // Be smart with large kernels to avoid duplicating their dependencies.
+ if (CurKernel.isLarge(LargeKernelThreshold)) {
+ assert(LargeKernelOverlapForMerge >= 0.0f &&
+ LargeKernelOverlapForMerge <= 1.0f);
+ SML << "Large Kernel: " << getName(*CurKernel.Fn)
+ << " - looking for partition with at least "
+ << format("%0.2f", LargeKernelOverlapForMerge * 100) << "% overlap\n";
+
+ bool Assigned = false;
+ for (const auto &[PID, Fns] : enumerate(Partitions)) {
+ float Overlap = calculateOverlap(CurKernel.Dependencies, Fns);
+ SML << " => " << format("%0.2f", Overlap * 100) << "% overlap with P"
+ << PID << '\n';
+ if (Overlap > LargeKernelOverlapForMerge) {
+ SML << " selecting P" << PID << '\n';
+ AssignToPartition(PID, CurKernel);
+ Assigned = true;
+ }
+ }
+
+ if (Assigned)
+ continue;
+ }
+
+ // Normal "load-balancing", assign to partition with least pressure.
+ auto [PID, CurCost] = BalancingQueue.back();
+ AssignToPartition(PID, CurKernel);
+ }
+
+ // Work is mostly done now, verify the partioning and add all functions we may
+ // have missed (= unreachable, or we don't understand how they're reached) to
+ // P0.
+ DenseSet<const Function *> AllFunctions;
+ for (const auto &[Idx, Part] : enumerate(Partitions)) {
+ CostType Cost = 0;
+ for (auto *Fn : Part) {
+ // external linkage functions should exclusively be in the first partition
+ // at this stage. In theory, we should only ever see external linkage
+ // functions here if they're kernels, or if they've been added due to a
+ // kernel using indirect calls somewhere in its CallGraph.
+ assert(Idx == 0 || (!Fn->hasExternalLinkage() || isEntryPoint(Fn)));
+ Cost += FnCosts.at(Fn);
+ }
+ SML << "P" << Idx << " has a total cost of " << Cost << " ("
+ << format("%0.2f", (float(Cost) / ModuleCost) * 100)
+ << "% of source module)\n";
+ AllFunctions.insert(Part.begin(), Part.end());
+ }
+
+ // Add missed functions to P0. This will take care of adding things like
+ // external functions with no callers in the module to P0. This should be
+ // fairly rare as AMDGPU internalizes everything in most cases, so unused
+ // internal functions would get removed.
+ for (auto &Fn : M) {
+ if (!Fn.isDeclaration() && !AllFunctions.contains(&Fn)) {
+ SML << getName(Fn) << " has no partition assigned, defaulting to P0\n";
+ Partitions[0].insert(&Fn);
+ }
+ }
+
+ SML << "--Partitioning Done--\n\n";
+
+ return Partitions;
+}
+
+static void externalize(GlobalValue &GV) {
+ if (GV.hasLocalLinkage()) {
+ GV.setLinkage(GlobalValue::ExternalLinkage);
+ GV.setVisibility(GlobalValue::HiddenVisibility);
+ }
+
+ // Unnamed entities must be named consistently between modules. setName will
+ // give a distinct name to each such entity.
+ if (!GV.hasName())
+ GV.setName("__llvmsplit_unnamed");
+}
+} // end anonymous namespace
+
+void llvm::splitAMDGPUModule(
+ const AMDGPUTargetMachine &TM, Module &M, unsigned N,
+ function_ref<void(std::unique_ptr<Module> MPart)> ModuleCallback) {
+
+ SplitModuleLogger SML(M);
+
+ CallGraph CG(M);
+
+ // Externalize functions whose address are taken.
+ //
+ // This is needed because partitioning is purely based on calls, but sometimes
+ // a kernel/function may just look at the address of another local function
+ // and not do anything (no calls). After partitioning, that local function may
+ // end up in a
diff erent module (so it's just a declaration in the module
+ // where its address is taken), which emits a "undefined hidden symbol" linker
+ // error.
+ //
+ // Additionally, it guides partitioning to not duplicate this function if it's
+ // called directly at some point.
+ for (auto &Fn : M) {
+ if (Fn.hasAddressTaken()) {
+ if (Fn.hasLocalLinkage()) {
+ SML << "[externalize] " << Fn.getName()
+ << " because its address is taken\n";
+ }
+ externalize(Fn);
+ }
+ }
+
+ // Externalize local GVs, which avoids duplicating their initializers, which
+ // in turns helps keep code size in check.
+ if (!NoExternalizeGlobals) {
+ for (auto &GV : M.globals()) {
+ if (GV.hasLocalLinkage())
+ SML << "[externalize] GV " << GV.getName() << '\n';
+ externalize(GV);
+ }
+ }
+
+ // Start by calculating the cost of every function in the module, as well as
+ // the module's overall cost.
+ DenseMap<const Function *, CostType> FnCosts;
+ const CostType ModuleCost = calculateFunctionCosts(SML, TM, M, FnCosts);
+
+ // Gather every kernel into a WorkList, then sort it by descending total cost
+ // of the kernel so the biggest kernels are seen first.
+ SmallVector<KernelWithDependencies> WorkList;
+ for (auto &Fn : M) {
+ if (isEntryPoint(&Fn) && !Fn.isDeclaration())
+ WorkList.emplace_back(SML, CG, FnCosts, &Fn);
+ }
+ sort(WorkList, [&](auto &A, auto &B) {
+ // Sort by total cost, and if the total cost is identical, sort
+ // alphabetically.
+ if (A.TotalCost == B.TotalCost)
+ return A.Fn->getName() < B.Fn->getName();
+ return A.TotalCost > B.TotalCost;
+ });
+
+ if (SML) {
+ SML << "Worklist\n";
+ for (const auto &KWD : WorkList) {
+ SML << "[Kernel] " << getName(*KWD.Fn) << " (totalCost:" << KWD.TotalCost
+ << " indirect:" << KWD.HasIndirectCall
+ << " hasNonDuplicatableDep:" << KWD.HasNonDuplicatableDependecy
+ << ")\n";
+ for (const auto *Dep : KWD.Dependencies)
+ SML << " [Dep] " << getName(*Dep) << '\n';
+ }
+ }
+
+ // This performs all of the partitioning work.
+ auto Partitions = doPartitioning(SML, M, N, ModuleCost, FnCosts, WorkList);
+ assert(Partitions.size() == N);
+
+ // If we didn't externalize GVs, then local GVs need to be conservatively
+ // imported into every module (including their initializers), and then cleaned
+ // up afterwards.
+ const auto NeedsConservativeImport = [&](const GlobalValue *GV) {
+ // We conservatively import private/internal GVs into every module and clean
+ // them up afterwards.
+ const auto *Var = dyn_cast<GlobalVariable>(GV);
+ return Var && Var->hasLocalLinkage();
+ };
+
+ SML << "Creating " << N << " modules...\n";
+ unsigned TotalFnImpls = 0;
+ for (unsigned I = 0; I < N; ++I) {
+ const auto &FnsInPart = Partitions[I];
+
+ ValueToValueMapTy VMap;
+ std::unique_ptr<Module> MPart(
+ CloneModule(M, VMap, [&](const GlobalValue *GV) {
+ // Functions go in their assigned partition.
+ if (const auto *Fn = dyn_cast<Function>(GV)) {
+// Check we don't import an external linkage function in any
+// partition other than P0.
+#ifndef NDEBUG
+ if (Fn->hasExternalLinkage() && !isEntryPoint(Fn)) {
+ assert((I == 0) == FnsInPart.contains(Fn));
+ }
+#endif
+ return FnsInPart.contains(Fn);
+ }
+
+ if (NeedsConservativeImport(GV))
+ return true;
+
+ // Everything else goes in the first partition.
+ return I == 0;
+ }));
+
+ // Clean-up conservatively imported GVs without any users.
+ for (auto &GV : make_early_inc_range(MPart->globals())) {
+ if (NeedsConservativeImport(&GV) && GV.use_empty())
+ GV.eraseFromParent();
+ }
+
+ unsigned NumAllFns = 0, NumKernels = 0;
+ for (auto &Cur : *MPart) {
+ if (!Cur.isDeclaration()) {
+ ++NumAllFns;
+ if (isEntryPoint(&Cur))
+ ++NumKernels;
+ }
+ }
+ TotalFnImpls += NumAllFns;
+ SML << " - Module " << I << " with " << NumAllFns << " functions ("
+ << NumKernels << " kernels)\n";
+ ModuleCallback(std::move(MPart));
+ }
+
+ SML << TotalFnImpls << " function definitions across all modules ("
+ << format("%0.2f", (float(TotalFnImpls) / FnCosts.size()) * 100)
+ << "% of original module)\n";
+}
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUSplitModule.h b/llvm/lib/Target/AMDGPU/AMDGPUSplitModule.h
new file mode 100644
index 00000000000000..6171643bd4adc4
--- /dev/null
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSplitModule.h
@@ -0,0 +1,30 @@
+//===- AMDGPUSplitModule.h -------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TARGET_AMDGPUSPLITMODULE_H
+#define LLVM_TARGET_AMDGPUSPLITMODULE_H
+
+#include "llvm/ADT/STLFunctionalExtras.h"
+#include <memory>
+
+namespace llvm {
+
+class Module;
+class AMDGPUTargetMachine;
+
+/// Splits the module M into N linkable partitions. The function ModuleCallback
+/// is called N times passing each individual partition as the MPart argument.
+void splitAMDGPUModule(
+ const AMDGPUTargetMachine &TM, Module &M, unsigned N,
+ function_ref<void(std::unique_ptr<Module> MPart)> ModuleCallback);
+
+} // end namespace llvm
+
+#endif // LLVM_TARGET_AMDGPUSPLITMODULE_H
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index 20329dea602759..dbbfe34a638635 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -21,6 +21,7 @@
#include "AMDGPUIGroupLP.h"
#include "AMDGPUMacroFusion.h"
#include "AMDGPURegBankSelect.h"
+#include "AMDGPUSplitModule.h"
#include "AMDGPUTargetObjectFile.h"
#include "AMDGPUTargetTransformInfo.h"
#include "AMDGPUUnifyDivergentExitNodes.h"
@@ -815,6 +816,13 @@ AMDGPUTargetMachine::getAddressSpaceForPseudoSourceKind(unsigned Kind) const {
return AMDGPUAS::FLAT_ADDRESS;
}
+bool AMDGPUTargetMachine::splitModule(
+ Module &M, unsigned NumParts,
+ function_ref<void(std::unique_ptr<Module> MPart)> ModuleCallback) const {
+ splitAMDGPUModule(*this, M, NumParts, ModuleCallback);
+ return true;
+}
+
//===----------------------------------------------------------------------===//
// GCN Target Machine (SI+)
//===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
index e48cb8fdc65769..2cfd232483a8a1 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
@@ -73,6 +73,10 @@ class AMDGPUTargetMachine : public LLVMTargetMachine {
getPredicatedAddrSpace(const Value *V) const override;
unsigned getAddressSpaceForPseudoSourceKind(unsigned Kind) const override;
+
+ bool splitModule(Module &M, unsigned NumParts,
+ function_ref<void(std::unique_ptr<Module> MPart)>
+ ModuleCallback) const override;
};
//===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/AMDGPU/CMakeLists.txt b/llvm/lib/Target/AMDGPU/CMakeLists.txt
index ead81b402eb767..c992352cb78da7 100644
--- a/llvm/lib/Target/AMDGPU/CMakeLists.txt
+++ b/llvm/lib/Target/AMDGPU/CMakeLists.txt
@@ -98,6 +98,7 @@ add_llvm_target(AMDGPUCodeGen
AMDGPURewriteOutArguments.cpp
AMDGPURewriteUndefForPHI.cpp
AMDGPUSetWavePriority.cpp
+ AMDGPUSplitModule.cpp
AMDGPUSubtarget.cpp
AMDGPUTargetMachine.cpp
AMDGPUTargetObjectFile.cpp
diff --git a/llvm/test/tools/llvm-split/AMDGPU/address-taken-externalize-with-call.ll b/llvm/test/tools/llvm-split/AMDGPU/address-taken-externalize-with-call.ll
new file mode 100644
index 00000000000000..8b76237efa3253
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/address-taken-externalize-with-call.ll
@@ -0,0 +1,46 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa -amdgpu-module-splitting-large-kernel-threshold=0
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; 3 kernels:
+; - A does a direct call to HelperA
+; - B is storing @HelperA
+; - C does a direct call to HelperA
+;
+; The helper functions will get externalized, which will force A and C into P0 as
+; external functions cannot be duplicated.
+
+; CHECK0: define hidden void @HelperA()
+; CHECK0: define amdgpu_kernel void @A()
+; CHECK0: declare amdgpu_kernel void @B(ptr)
+; CHECK0: define amdgpu_kernel void @C()
+
+; CHECK1: declare hidden void @HelperA()
+; CHECK1: declare amdgpu_kernel void @A()
+; CHECK1: declare amdgpu_kernel void @B(ptr)
+; CHECK1: declare amdgpu_kernel void @C()
+
+; CHECK2: declare hidden void @HelperA()
+; CHECK2: declare amdgpu_kernel void @A()
+; CHECK2: define amdgpu_kernel void @B(ptr %dst)
+; CHECK2: declare amdgpu_kernel void @C()
+
+define internal void @HelperA() {
+ ret void
+}
+
+define amdgpu_kernel void @A() {
+ call void @HelperA()
+ ret void
+}
+
+define amdgpu_kernel void @B(ptr %dst) {
+ store ptr @HelperA, ptr %dst
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ call void @HelperA()
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/address-taken-externalize.ll b/llvm/test/tools/llvm-split/AMDGPU/address-taken-externalize.ll
new file mode 100644
index 00000000000000..46d7d9783aeae0
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/address-taken-externalize.ll
@@ -0,0 +1,37 @@
+; RUN: llvm-split -o %t %s -j 2 -mtriple amdgcn-amd-amdhsa -amdgpu-module-splitting-large-kernel-threshold=0
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+
+; 2 kernels:
+; - A is isolated
+; - B is storing @HelperA/B's address
+;
+; The helper functions should get externalized (become hidden w/ external linkage)
+
+; CHECK0: define hidden void @HelperA()
+; CHECK0: define hidden void @HelperB()
+; CHECK0: define amdgpu_kernel void @A()
+; CHECK0: declare amdgpu_kernel void @B(i1, ptr)
+
+; CHECK1: declare hidden void @HelperA()
+; CHECK1: declare hidden void @HelperB()
+; CHECK1: declare amdgpu_kernel void @A()
+; CHECK1: define amdgpu_kernel void @B(i1 %cond, ptr %dst)
+
+define internal void @HelperA() {
+ ret void
+}
+
+define internal void @HelperB() {
+ ret void
+}
+
+define amdgpu_kernel void @A() {
+ ret void
+}
+
+define amdgpu_kernel void @B(i1 %cond, ptr %dst) {
+ %addr = select i1 %cond, ptr @HelperA, ptr @HelperB
+ store ptr %addr, ptr %dst
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/debug-name-hiding.ll b/llvm/test/tools/llvm-split/AMDGPU/debug-name-hiding.ll
new file mode 100644
index 00000000000000..6a07ed51ba1beb
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/debug-name-hiding.ll
@@ -0,0 +1,20 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa -debug -amdgpu-module-splitting-log-private 2>&1 | FileCheck %s --implicit-check-not=MyCustomKernel
+; REQUIRES: asserts
+
+; SHA256 of the kernel names.
+
+; CHECK: a097723d21cf9f35d90e6fb7881995ac8c398b3366a6c97efc657404f9fe301c
+; CHECK: 626bc23242de8fcfda7f0e66318d29455c081df6b5380e64d14703c95fcbcd59
+; CHECK: c38d90a7ca71dc5d694bb9e093dadcdedfc4cb4adf7ed7e46d42fe95a0b4ef55
+
+define amdgpu_kernel void @MyCustomKernel0() {
+ ret void
+}
+
+define amdgpu_kernel void @MyCustomKernel1() {
+ ret void
+}
+
+define amdgpu_kernel void @MyCustomKernel2() {
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-alias-dependencies.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-alias-dependencies.ll
new file mode 100644
index 00000000000000..c2746d1398924c
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-alias-dependencies.ll
@@ -0,0 +1,45 @@
+; RUN: llvm-split -o %t %s -j 2 -mtriple amdgcn-amd-amdhsa
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+
+; 3 kernels:
+; - A calls nothing
+; - B calls @PerryThePlatypus
+; - C calls @Perry, an alias of @PerryThePlatypus
+;
+; We should see through the alias and put B/C in the same
+; partition.
+;
+; Additionally, @PerryThePlatypus gets externalized as
+; the alias counts as taking its address.
+
+; CHECK0-NOT: define
+; CHECK0: @Perry = internal alias ptr (), ptr @PerryThePlatypus
+; CHECK0: define hidden void @PerryThePlatypus()
+; CHECK0: define amdgpu_kernel void @B
+; CHECK0: define amdgpu_kernel void @C
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: define amdgpu_kernel void @A
+; CHECK1-NOT: define
+
+ at Perry = internal alias ptr(), ptr @PerryThePlatypus
+
+define internal void @PerryThePlatypus() {
+ ret void
+}
+
+define amdgpu_kernel void @A() {
+ ret void
+}
+
+define amdgpu_kernel void @B() {
+ call void @PerryThePlatypus()
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ call void @Perry()
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-cost-ranking.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-cost-ranking.ll
new file mode 100644
index 00000000000000..4635264aefb39a
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-cost-ranking.ll
@@ -0,0 +1,54 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; 3 kernels with each their own dependencies should go into 3
+; distinct partitions. The most expensive kernel should be
+; seen first and go into the last partition.
+
+; CHECK0-NOT: define
+; CHECK0: define amdgpu_kernel void @C
+; CHECK0: define internal void @HelperC
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: define amdgpu_kernel void @A
+; CHECK1: define internal void @HelperA
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: define amdgpu_kernel void @B
+; CHECK2: define internal void @HelperB
+; CHECK2-NOT: define
+
+
+define amdgpu_kernel void @A() {
+ call void @HelperA()
+ ret void
+}
+
+define internal void @HelperA() {
+ ret void
+}
+
+define amdgpu_kernel void @B(ptr %x) {
+ store i64 42, ptr %x
+ store i64 43, ptr %x
+ store i64 44, ptr %x
+ call void @HelperB()
+ ret void
+}
+
+define internal void @HelperB() {
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ call void @HelperC()
+ ret void
+}
+
+define internal void @HelperC() {
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-dependencies.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-dependencies.ll
new file mode 100644
index 00000000000000..bea527f15bbaaf
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-dependencies.ll
@@ -0,0 +1,50 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; 3 kernels with each their own dependencies should go into 3
+; distinct partitions.
+
+; CHECK0-NOT: define
+; CHECK0: define amdgpu_kernel void @C
+; CHECK0: define internal void @HelperC
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: define amdgpu_kernel void @B
+; CHECK1: define internal void @HelperB
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: define amdgpu_kernel void @A
+; CHECK2: define internal void @HelperA
+; CHECK2-NOT: define
+
+
+define amdgpu_kernel void @A() {
+ call void @HelperA()
+ ret void
+}
+
+define internal void @HelperA() {
+ ret void
+}
+
+define amdgpu_kernel void @B() {
+ call void @HelperB()
+ ret void
+}
+
+define internal void @HelperB() {
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ call void @HelperC()
+ ret void
+}
+
+define internal void @HelperC() {
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-duplication.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-duplication.ll
new file mode 100644
index 00000000000000..64839f8d8456ad
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-duplication.ll
@@ -0,0 +1,41 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; 3 kernels share a common helper, that helper should be
+; cloned in all partitions.
+
+; CHECK0-NOT: define
+; CHECK0: define internal void @Helper
+; CHECK0: define amdgpu_kernel void @C
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: define internal void @Helper
+; CHECK1: define amdgpu_kernel void @B
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: define internal void @Helper
+; CHECK2: define amdgpu_kernel void @A
+; CHECK2-NOT: define
+
+define internal void @Helper() {
+ ret void
+}
+
+define amdgpu_kernel void @A() {
+ call void @Helper()
+ ret void
+}
+
+define amdgpu_kernel void @B() {
+ call void @Helper()
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ call void @Helper()
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-external.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-external.ll
new file mode 100644
index 00000000000000..435e97a5813400
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-external.ll
@@ -0,0 +1,64 @@
+; RUN: llvm-split -o %t %s -j 4 -mtriple amdgcn-amd-amdhsa
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+; RUN: llvm-dis -o - %t3 | FileCheck --check-prefix=CHECK3 %s
+
+; Both overridable helper should go in P0.
+
+; CHECK0-NOT: define
+; CHECK0: define available_externally void @OverridableHelper0()
+; CHECK0: define internal void @OverridableHelper1()
+; CHECK0: define amdgpu_kernel void @A
+; CHECK0: define amdgpu_kernel void @B
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: define internal void @PrivateHelper1()
+; CHECK2: define amdgpu_kernel void @D
+; CHECK2-NOT: define
+
+; CHECK3-NOT: define
+; CHECK3: define internal void @PrivateHelper0()
+; CHECK3: define amdgpu_kernel void @C
+; CHECK3-NOT: define
+
+define available_externally void @OverridableHelper0() {
+ ret void
+}
+
+define internal void @OverridableHelper1() #0 {
+ ret void
+}
+
+define internal void @PrivateHelper0() {
+ ret void
+}
+
+define internal void @PrivateHelper1() {
+ ret void
+}
+
+define amdgpu_kernel void @A() {
+ call void @OverridableHelper0()
+ ret void
+}
+
+define amdgpu_kernel void @B() {
+ call void @OverridableHelper1()
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ call void @PrivateHelper0()
+ ret void
+}
+
+define amdgpu_kernel void @D() {
+ call void @PrivateHelper1()
+ ret void
+}
+
+attributes #0 = { nobuiltin }
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-indirect.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-indirect.ll
new file mode 100644
index 00000000000000..9701ac35ce54ee
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-indirect.ll
@@ -0,0 +1,76 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; We have 4 kernels:
+; - Each kernel has an internal helper
+; - @A and @B's helpers does an indirect call.
+;
+; We default to putting A/B in P0, alongside a copy
+; of all helpers who have their address taken.
+; The other kernels can still go into separate partitions.
+
+; CHECK0-NOT: define
+; CHECK0: define hidden void @HelperA
+; CHECK0: define hidden void @HelperB
+; CHECK0: define hidden void @CallCandidate
+; CHECK0-NOT: define {{.*}} @HelperC
+; CHECK0-NOT: define {{.*}} @HelperD
+; CHECK0: define amdgpu_kernel void @A
+; CHECK0: define amdgpu_kernel void @B
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: define internal void @HelperD
+; CHECK1: define amdgpu_kernel void @D
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: define internal void @HelperC
+; CHECK2: define amdgpu_kernel void @C
+; CHECK2-NOT: define
+
+ at addrthief = global [3 x ptr] [ptr @HelperA, ptr @HelperB, ptr @CallCandidate]
+
+define internal void @HelperA(ptr %call) {
+ call void %call()
+ ret void
+}
+
+define internal void @HelperB(ptr %call) {
+ call void %call()
+ ret void
+}
+
+define internal void @CallCandidate() {
+ ret void
+}
+
+define internal void @HelperC() {
+ ret void
+}
+
+define internal void @HelperD() {
+ ret void
+}
+
+define amdgpu_kernel void @A(ptr %call) {
+ call void @HelperA(ptr %call)
+ ret void
+}
+
+define amdgpu_kernel void @B(ptr %call) {
+ call void @HelperB(ptr %call)
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ call void @HelperC()
+ ret void
+}
+
+define amdgpu_kernel void @D() {
+ call void @HelperD()
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-overridable.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-overridable.ll
new file mode 100644
index 00000000000000..dc2c5c3c07bee6
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-dependency-overridable.ll
@@ -0,0 +1,40 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; CHECK0-NOT: define
+; CHECK0: define void @ExternalHelper
+; CHECK0: define amdgpu_kernel void @A
+; CHECK0: define amdgpu_kernel void @B
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: define amdgpu_kernel void @D
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: define amdgpu_kernel void @C
+; CHECK2-NOT: define
+
+define void @ExternalHelper() {
+ ret void
+}
+
+define amdgpu_kernel void @A() {
+ call void @ExternalHelper()
+ ret void
+}
+
+define amdgpu_kernel void @B() {
+ call void @ExternalHelper()
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ ret void
+}
+
+define amdgpu_kernel void @D() {
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-global-variables-noexternal.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-global-variables-noexternal.ll
new file mode 100644
index 00000000000000..0fc76934afc548
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-global-variables-noexternal.ll
@@ -0,0 +1,42 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa -amdgpu-module-splitting-no-externalize-globals
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; 3 kernels use private/internal global variables.
+; The GVs should be copied in each partition as needed.
+
+; CHECK0-NOT: define
+; CHECK0: @bar = internal constant ptr
+; CHECK0: define amdgpu_kernel void @C
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: @foo = private constant ptr
+; CHECK1: define amdgpu_kernel void @A
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: @foo = private constant ptr
+; CHECK2: @bar = internal constant ptr
+; CHECK2: define amdgpu_kernel void @B
+; CHECK2-NOT: define
+
+ at foo = private constant ptr poison
+ at bar = internal constant ptr poison
+
+define amdgpu_kernel void @A() {
+ store i32 42, ptr @foo
+ ret void
+}
+
+define amdgpu_kernel void @B() {
+ store i32 42, ptr @foo
+ store i32 42, ptr @bar
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ store i32 42, ptr @bar
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-global-variables.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-global-variables.ll
new file mode 100644
index 00000000000000..7564662e7c7c0c
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-global-variables.ll
@@ -0,0 +1,44 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; 3 kernels use private/internal global variables.
+; The GVs should be copied in each partition as needed.
+
+; CHECK0-NOT: define
+; CHECK0: @foo = hidden constant ptr poison
+; CHECK0: @bar = hidden constant ptr poison
+; CHECK0: define amdgpu_kernel void @C
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: @foo = external hidden constant ptr{{$}}
+; CHECK1: @bar = external hidden constant ptr{{$}}
+; CHECK1: define amdgpu_kernel void @A
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: @foo = external hidden constant ptr{{$}}
+; CHECK2: @bar = external hidden constant ptr{{$}}
+; CHECK2: define amdgpu_kernel void @B
+; CHECK2-NOT: define
+
+ at foo = private constant ptr poison
+ at bar = internal constant ptr poison
+
+define amdgpu_kernel void @A() {
+ store i32 42, ptr @foo
+ ret void
+}
+
+define amdgpu_kernel void @B() {
+ store i32 42, ptr @foo
+ store i32 42, ptr @bar
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ store i32 42, ptr @bar
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-load-balancing.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-load-balancing.ll
new file mode 100644
index 00000000000000..5dfb95c5fc6608
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-load-balancing.ll
@@ -0,0 +1,75 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; Test load balancing logic with 6 kernels.
+;
+; Kernels go from most expensive (A == 6) to least expensive (F == 1)
+;
+; Load balancing should work like this (current partition cost is in parens)
+;
+; Initial -> [P0(0), P1(0), P2(0)]
+;
+; A(6) goes in 2 -> [P2(6), P0(0), P1(0)]
+; B(5) goes in 1 -> [P2(6), P1(5), P0(4)]
+; C(4) goes in 0 -> [P2(6), P1(5), P0(4)]
+
+; D(3) goes in 0 -> [P0(7), P2(6), P1(5)]
+; E(2) goes in 1 -> [P0(7), P1(7), P2(6)]
+; F(1) goes in 2 -> [P0(7), P1(7), P2(7)]
+
+; CHECK0-NOT: define
+; CHECK0: define amdgpu_kernel void @C
+; CHECK0: define amdgpu_kernel void @D
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: define amdgpu_kernel void @B
+; CHECK1: define amdgpu_kernel void @E
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: define amdgpu_kernel void @A
+; CHECK2: define amdgpu_kernel void @F
+; CHECK2-NOT: define
+
+
+define amdgpu_kernel void @A(ptr %x) {
+ store i64 42, ptr %x
+ store i64 43, ptr %x
+ store i64 44, ptr %x
+ store i64 45, ptr %x
+ store i64 46, ptr %x
+ ret void
+}
+
+define amdgpu_kernel void @B(ptr %x) {
+ store i64 42, ptr %x
+ store i64 43, ptr %x
+ store i64 44, ptr %x
+ store i64 45, ptr %x
+ ret void
+}
+
+define amdgpu_kernel void @C(ptr %x) {
+ store i64 42, ptr %x
+ store i64 43, ptr %x
+ store i64 44, ptr %x
+ ret void
+}
+
+define amdgpu_kernel void @D(ptr %x) {
+ store i64 42, ptr %x
+ store i64 43, ptr %x
+ ret void
+}
+
+define amdgpu_kernel void @E(ptr %x) {
+ store i64 42, ptr %x
+ ret void
+}
+
+define amdgpu_kernel void @F() {
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/kernels-no-dependencies.ll b/llvm/test/tools/llvm-split/AMDGPU/kernels-no-dependencies.ll
new file mode 100644
index 00000000000000..8959acfcae542a
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/kernels-no-dependencies.ll
@@ -0,0 +1,39 @@
+; RUN: llvm-split -o %t %s -j 4 -mtriple amdgcn-amd-amdhsa
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+; RUN: llvm-dis -o - %t3 | FileCheck --check-prefix=CHECK3 %s
+
+; Check that 4 independent kernels get put into 4
diff erent partitions.
+
+; CHECK0-NOT: define
+; CHECK0: define amdgpu_kernel void @D
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: define amdgpu_kernel void @C
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: define amdgpu_kernel void @B
+; CHECK2-NOT: define
+
+; CHECK3-NOT: define
+; CHECK3: define amdgpu_kernel void @A
+; CHECK3-NOT: define
+
+define amdgpu_kernel void @A() {
+ ret void
+}
+
+define amdgpu_kernel void @B() {
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ ret void
+}
+
+define amdgpu_kernel void @D() {
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/large-kernels-merging.ll b/llvm/test/tools/llvm-split/AMDGPU/large-kernels-merging.ll
new file mode 100644
index 00000000000000..4fdbac7d17897d
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/large-kernels-merging.ll
@@ -0,0 +1,98 @@
+; RUN: llvm-split -o %t %s -j 3 -mtriple amdgcn-amd-amdhsa -amdgpu-module-splitting-large-kernel-threshold=1.2 -amdgpu-module-splitting-large-kernel-merge-overlap=0.5
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; RUN: llvm-split -o %t.nolarge %s -j 3 -mtriple amdgcn-amd-amdhsa -amdgpu-module-splitting-large-kernel-threshold=0
+; RUN: llvm-dis -o - %t.nolarge0 | FileCheck --check-prefix=NOLARGEKERNELS-CHECK0 %s
+; RUN: llvm-dis -o - %t.nolarge1 | FileCheck --check-prefix=NOLARGEKERNELS-CHECK1 %s
+; RUN: llvm-dis -o - %t.nolarge2 | FileCheck --check-prefix=NOLARGEKERNELS-CHECK2 %s
+
+; 2 kernels (A/B) are large and share all their dependencies.
+; They should go in the same partition, the remaining kernel should
+; go somewhere else, and one partition should be empty.
+;
+; Also check w/o large kernels processing to verify they are indeed handled
+;
diff erently.
+
+; CHECK0-NOT: define
+
+; CHECK1-NOT: define
+; CHECK1: define internal void @HelperC()
+; CHECK1: define amdgpu_kernel void @C
+; CHECK1-NOT: define
+
+; CHECK2-NOT: define
+; CHECK2: define internal void @large2()
+; CHECK2: define internal void @large1()
+; CHECK2: define internal void @large0()
+; CHECK2: define internal void @HelperA()
+; CHECK2: define internal void @HelperB()
+; CHECK2: define amdgpu_kernel void @A
+; CHECK2: define amdgpu_kernel void @B
+; CHECK2-NOT: define
+
+; NOLARGEKERNELS-CHECK0-NOT: define
+; NOLARGEKERNELS-CHECK0: define internal void @HelperC()
+; NOLARGEKERNELS-CHECK0: define amdgpu_kernel void @C
+; NOLARGEKERNELS-CHECK0-NOT: define
+
+; NOLARGEKERNELS-CHECK1: define internal void @large2()
+; NOLARGEKERNELS-CHECK1: define internal void @large1()
+; NOLARGEKERNELS-CHECK1: define internal void @large0()
+; NOLARGEKERNELS-CHECK1: define internal void @HelperB()
+; NOLARGEKERNELS-CHECK1: define amdgpu_kernel void @B
+
+; NOLARGEKERNELS-CHECK2: define internal void @large2()
+; NOLARGEKERNELS-CHECK2: define internal void @large1()
+; NOLARGEKERNELS-CHECK2: define internal void @large0()
+; NOLARGEKERNELS-CHECK2: define internal void @HelperA()
+; NOLARGEKERNELS-CHECK2: define amdgpu_kernel void @A
+
+define internal void @large2() {
+ store volatile i32 42, ptr null
+ call void @large2()
+ ret void
+}
+
+define internal void @large1() {
+ call void @large1()
+ call void @large2()
+ ret void
+}
+
+define internal void @large0() {
+ call void @large0()
+ call void @large1()
+ call void @large2()
+ ret void
+}
+
+define internal void @HelperA() {
+ call void @large0()
+ ret void
+}
+
+define internal void @HelperB() {
+ call void @large0()
+ ret void
+}
+
+define amdgpu_kernel void @A() {
+ call void @HelperA()
+ ret void
+}
+
+define amdgpu_kernel void @B() {
+ call void @HelperB()
+ ret void
+}
+
+define internal void @HelperC() {
+ ret void
+}
+
+define amdgpu_kernel void @C() {
+ call void @HelperC()
+ ret void
+}
diff --git a/llvm/test/tools/llvm-split/AMDGPU/lit.local.cfg b/llvm/test/tools/llvm-split/AMDGPU/lit.local.cfg
new file mode 100644
index 00000000000000..6154a6c1c9061a
--- /dev/null
+++ b/llvm/test/tools/llvm-split/AMDGPU/lit.local.cfg
@@ -0,0 +1,2 @@
+if not "AMDGPU" in config.root.targets:
+ config.unsupported = True
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