[llvm] r253954 - Add a FunctionImporter helper to perform summary-based cross-module function importing
Mehdi Amini via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 23 22:07:49 PST 2015
Author: mehdi_amini
Date: Tue Nov 24 00:07:49 2015
New Revision: 253954
URL: http://llvm.org/viewvc/llvm-project?rev=253954&view=rev
Log:
Add a FunctionImporter helper to perform summary-based cross-module function importing
Summary:
This is a helper to perform cross-module import for ThinLTO. Right now
it is importing naively every possible called functions.
Reviewers: tejohnson
Subscribers: dexonsmith, llvm-commits
Differential Revision: http://reviews.llvm.org/D14914
From: Mehdi Amini <mehdi.amini at apple.com>
Added:
llvm/trunk/include/llvm/Transforms/IPO/FunctionImport.h
llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
llvm/trunk/test/Transforms/FunctionImport/
llvm/trunk/test/Transforms/FunctionImport/Inputs/
llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport.ll
llvm/trunk/test/Transforms/FunctionImport/funcimport.ll
Modified:
llvm/trunk/include/llvm/InitializePasses.h
llvm/trunk/lib/Transforms/IPO/CMakeLists.txt
llvm/trunk/lib/Transforms/IPO/IPO.cpp
llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt
Modified: llvm/trunk/include/llvm/InitializePasses.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/InitializePasses.h?rev=253954&r1=253953&r2=253954&view=diff
==============================================================================
--- llvm/trunk/include/llvm/InitializePasses.h (original)
+++ llvm/trunk/include/llvm/InitializePasses.h Tue Nov 24 00:07:49 2015
@@ -302,6 +302,7 @@ void initializeSjLjEHPreparePass(PassReg
void initializeDemandedBitsPass(PassRegistry&);
void initializeFuncletLayoutPass(PassRegistry &);
void initializeLoopLoadEliminationPass(PassRegistry&);
+void initializeFunctionImportPassPass(PassRegistry &);
}
#endif
Added: llvm/trunk/include/llvm/Transforms/IPO/FunctionImport.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/IPO/FunctionImport.h?rev=253954&view=auto
==============================================================================
--- llvm/trunk/include/llvm/Transforms/IPO/FunctionImport.h (added)
+++ llvm/trunk/include/llvm/Transforms/IPO/FunctionImport.h Tue Nov 24 00:07:49 2015
@@ -0,0 +1,51 @@
+//===- llvm/Transforms/IPO/FunctionImport.h - ThinLTO importing -*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUNCTIONIMPORT_H
+#define LLVM_FUNCTIONIMPORT_H
+
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/ADT/StringMap.h"
+
+namespace llvm {
+class LLVMContext;
+class Module;
+class FunctionInfoIndex;
+
+/// The function importer is automatically importing function from other modules
+/// based on the provided summary informations.
+class FunctionImporter {
+
+ /// Cache of lazily loaded module for import.
+ StringMap<std::unique_ptr<Module>> ModuleMap;
+
+ /// The context that will be used for importing.
+ LLVMContext &Context;
+
+ /// The summaries index used to trigger importing.
+ const FunctionInfoIndex &Index;
+
+ /// Diagnostic will be sent to this handler.
+ DiagnosticHandlerFunction DiagnosticHandler;
+
+ /// Retrieve a Module from the cache or lazily load it on demand.
+ Module &getOrLoadModule(StringRef FileName);
+
+public:
+ /// Create a Function Importer.
+ FunctionImporter(LLVMContext &Context, const FunctionInfoIndex &Index,
+ DiagnosticHandlerFunction DiagnosticHandler)
+ : Context(Context), Index(Index), DiagnosticHandler(DiagnosticHandler) {}
+
+ /// Import functions in Module \p M based on the summary informations.
+ bool importFunctions(Module &M);
+};
+}
+
+#endif // LLVM_FUNCTIONIMPORT_H
Modified: llvm/trunk/lib/Transforms/IPO/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/CMakeLists.txt?rev=253954&r1=253953&r2=253954&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/CMakeLists.txt (original)
+++ llvm/trunk/lib/Transforms/IPO/CMakeLists.txt Tue Nov 24 00:07:49 2015
@@ -6,6 +6,7 @@ add_llvm_library(LLVMipo
ElimAvailExtern.cpp
ExtractGV.cpp
FunctionAttrs.cpp
+ FunctionImport.cpp
GlobalDCE.cpp
GlobalOpt.cpp
IPConstantPropagation.cpp
Added: llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp?rev=253954&view=auto
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp (added)
+++ llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp Tue Nov 24 00:07:49 2015
@@ -0,0 +1,239 @@
+//===- FunctionImport.cpp - ThinLTO Summary-based Function Import ---------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements Function import based on summaries.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/IPO/FunctionImport.h"
+
+#include "llvm/ADT/StringSet.h"
+#include "llvm/IR/AutoUpgrade.h"
+#include "llvm/IR/DiagnosticPrinter.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IRReader/IRReader.h"
+#include "llvm/Linker/Linker.h"
+#include "llvm/Object/FunctionIndexObjectFile.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/SourceMgr.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "function-import"
+
+// Load lazily a module from \p FileName in \p Context.
+static std::unique_ptr<Module> loadFile(const std::string &FileName,
+ LLVMContext &Context) {
+ SMDiagnostic Err;
+ DEBUG(dbgs() << "Loading '" << FileName << "'\n");
+ std::unique_ptr<Module> Result = getLazyIRFileModule(FileName, Err, Context);
+ if (!Result) {
+ Err.print("function-import", errs());
+ return nullptr;
+ }
+
+ Result->materializeMetadata();
+ UpgradeDebugInfo(*Result);
+
+ return Result;
+}
+
+// Get a Module for \p FileName from the cache, or load it lazily.
+Module &FunctionImporter::getOrLoadModule(StringRef FileName) {
+ auto &Module = ModuleMap[FileName];
+ if (!Module)
+ Module = loadFile(FileName, Context);
+ return *Module;
+}
+
+// Automatically import functions in Module \p M based on the summaries index.
+//
+// The current implementation imports every called functions that exists in the
+// summaries index.
+bool FunctionImporter::importFunctions(Module &M) {
+ assert(&Context == &M.getContext());
+
+ bool Changed = false;
+
+ /// First step is collecting the called functions and the one defined in this
+ /// module.
+ StringSet<> CalledFunctions;
+ for (auto &F : M) {
+ if (F.isDeclaration() || F.hasFnAttribute(Attribute::OptimizeNone))
+ continue;
+ for (auto &BB : F) {
+ for (auto &I : BB) {
+ if (isa<CallInst>(I)) {
+ DEBUG(dbgs() << "Found a call: '" << I << "'\n");
+ auto CalledFunction = cast<CallInst>(I).getCalledFunction();
+ if (CalledFunction && CalledFunction->hasName() &&
+ CalledFunction->isDeclaration())
+ CalledFunctions.insert(CalledFunction->getName());
+ }
+ }
+ }
+ }
+
+ /// Second step: for every call to an external function, try to import it.
+
+ // Linker that will be used for importing function
+ Linker L(&M, DiagnosticHandler);
+
+ /// Insert initial called function set in a worklist, so that we can add
+ /// transively called functions when importing.
+ SmallVector<StringRef, 64> Worklist;
+ for (auto &CalledFunction : CalledFunctions)
+ Worklist.push_back(CalledFunction.first());
+
+ while (!Worklist.empty()) {
+ auto CalledFunctionName = Worklist.pop_back_val();
+ DEBUG(dbgs() << "Process import for " << CalledFunctionName << "\n");
+
+ // Try to get a summary for this function call.
+ auto InfoList = Index.findFunctionInfoList(CalledFunctionName);
+ if (InfoList == Index.end()) {
+ DEBUG(dbgs() << "No summary for " << CalledFunctionName
+ << " Ignoring.\n");
+ continue;
+ }
+ assert(!InfoList->second.empty() && "No summary, error at import?");
+
+ // Comdat can have multiple entries, FIXME: what do we do with them?
+ auto &Info = InfoList->second[0];
+ assert(Info && "Nullptr in list, error importing summaries?\n");
+
+ auto *Summary = Info->functionSummary();
+ if (!Summary) {
+ // FIXME: in case we are lazyloading summaries, we can do it now.
+ dbgs() << "Missing summary for " << CalledFunctionName
+ << ", error at import?\n";
+ llvm_unreachable("Missing summary");
+ }
+
+ //
+ // No profitability notion right now, just import all the time...
+ //
+
+ // Get the module path from the summary.
+ auto FileName = Summary->modulePath();
+ DEBUG(dbgs() << "Importing " << CalledFunctionName << " from " << FileName
+ << "\n");
+
+ // Get the module for the import (potentially from the cache).
+ auto &Module = getOrLoadModule(FileName);
+
+ // The function that we will import!
+ GlobalValue *SGV = Module.getNamedValue(CalledFunctionName);
+ Function *F = dyn_cast<Function>(SGV);
+ if (!F && isa<GlobalAlias>(SGV)) {
+ auto *SGA = dyn_cast<GlobalAlias>(SGV);
+ F = dyn_cast<Function>(SGA->getBaseObject());
+ }
+ if (!F) {
+ errs() << "Can't load function '" << CalledFunctionName << "' in Module '"
+ << FileName << "', error in the summary?\n";
+ llvm_unreachable("Can't load function in Module");
+ }
+
+ // We cannot import weak_any functions without possibly affecting the
+ // order they are seen and selected by the linker, changing program
+ // semantics.
+ if (F->hasWeakAnyLinkage()) {
+ DEBUG(dbgs() << "Ignoring import request for weak-any function "
+ << CalledFunctionName << " from " << FileName << "\n");
+ continue;
+ }
+
+ // Link in the specified function.
+ if (L.linkInModule(&Module, Linker::Flags::None, &Index, F))
+ report_fatal_error("Function Import: link error");
+
+ // TODO: Process the newly imported function and add callees to the
+ // worklist.
+
+ Changed = true;
+ }
+ return Changed;
+}
+
+/// Summary file to use for function importing when using -function-import from
+/// the command line.
+static cl::opt<std::string>
+ SummaryFile("summary-file",
+ cl::desc("The summary file to use for function importing."));
+
+static void diagnosticHandler(const DiagnosticInfo &DI) {
+ raw_ostream &OS = errs();
+ DiagnosticPrinterRawOStream DP(OS);
+ DI.print(DP);
+ OS << '\n';
+}
+
+/// Parse the function index out of an IR file and return the function
+/// index object if found, or nullptr if not.
+static std::unique_ptr<FunctionInfoIndex>
+getFunctionIndexForFile(StringRef Path, std::string &Error,
+ DiagnosticHandlerFunction DiagnosticHandler) {
+ std::unique_ptr<MemoryBuffer> Buffer;
+ ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
+ MemoryBuffer::getFile(Path);
+ if (std::error_code EC = BufferOrErr.getError()) {
+ Error = EC.message();
+ return nullptr;
+ }
+ Buffer = std::move(BufferOrErr.get());
+ ErrorOr<std::unique_ptr<object::FunctionIndexObjectFile>> ObjOrErr =
+ object::FunctionIndexObjectFile::create(Buffer->getMemBufferRef(),
+ DiagnosticHandler);
+ if (std::error_code EC = ObjOrErr.getError()) {
+ Error = EC.message();
+ return nullptr;
+ }
+ return (*ObjOrErr)->takeIndex();
+}
+
+/// Pass that performs cross-module function import provided a summary file.
+class FunctionImportPass : public ModulePass {
+
+public:
+ /// Pass identification, replacement for typeid
+ static char ID;
+
+ explicit FunctionImportPass() : ModulePass(ID) {}
+
+ bool runOnModule(Module &M) override {
+ if (SummaryFile.empty()) {
+ report_fatal_error("error: -function-import requires -summary-file\n");
+ }
+ std::string Error;
+ std::unique_ptr<FunctionInfoIndex> Index =
+ getFunctionIndexForFile(SummaryFile, Error, diagnosticHandler);
+ if (!Index) {
+ errs() << "Error loading file '" << SummaryFile << "': " << Error << "\n";
+ return false;
+ }
+
+ // Perform the import now.
+ FunctionImporter Importer(M.getContext(), *Index, diagnosticHandler);
+ return Importer.importFunctions(M);
+
+ return false;
+ }
+};
+
+char FunctionImportPass::ID = 0;
+INITIALIZE_PASS_BEGIN(FunctionImportPass, "function-import",
+ "Summary Based Function Import", false, false)
+INITIALIZE_PASS_END(FunctionImportPass, "function-import",
+ "Summary Based Function Import", false, false)
+
+namespace llvm {
+Pass *createFunctionImportPass() { return new FunctionImportPass(); }
+}
Modified: llvm/trunk/lib/Transforms/IPO/IPO.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/IPO.cpp?rev=253954&r1=253953&r2=253954&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/IPO.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/IPO.cpp Tue Nov 24 00:07:49 2015
@@ -48,6 +48,7 @@ void llvm::initializeIPO(PassRegistry &R
initializeBarrierNoopPass(Registry);
initializeEliminateAvailableExternallyPass(Registry);
initializeSampleProfileLoaderPass(Registry);
+ initializeFunctionImportPassPass(Registry);
}
void LLVMInitializeIPO(LLVMPassRegistryRef R) {
Modified: llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt?rev=253954&r1=253953&r2=253954&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt (original)
+++ llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt Tue Nov 24 00:07:49 2015
@@ -20,4 +20,4 @@ type = Library
name = IPO
parent = Transforms
library_name = ipo
-required_libraries = Analysis Core InstCombine ProfileData Scalar Support TransformUtils Vectorize
+required_libraries = Analysis Core InstCombine Linker ProfileData Scalar Support TransformUtils Vectorize
Added: llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport.ll?rev=253954&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport.ll (added)
+++ llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport.ll Tue Nov 24 00:07:49 2015
@@ -0,0 +1,93 @@
+ at globalvar = global i32 1, align 4
+ at staticvar = internal global i32 1, align 4
+ at staticconstvar = internal unnamed_addr constant [2 x i32] [i32 10, i32 20], align 4
+ at commonvar = common global i32 0, align 4
+ at P = internal global void ()* null, align 8
+
+ at weakalias = weak alias void (...), bitcast (void ()* @globalfunc1 to void (...)*)
+ at analias = alias void (...), bitcast (void ()* @globalfunc2 to void (...)*)
+ at linkoncealias = alias void (...), bitcast (void ()* @linkoncefunc to void (...)*)
+
+define void @globalfunc1() #0 {
+entry:
+ ret void
+}
+
+define void @globalfunc2() #0 {
+entry:
+ ret void
+}
+
+define linkonce_odr void @linkoncefunc() #0 {
+entry:
+ ret void
+}
+
+define i32 @referencestatics(i32 %i) #0 {
+entry:
+ %i.addr = alloca i32, align 4
+ store i32 %i, i32* %i.addr, align 4
+ %call = call i32 @staticfunc()
+ %0 = load i32, i32* @staticvar, align 4
+ %add = add nsw i32 %call, %0
+ %1 = load i32, i32* %i.addr, align 4
+ %idxprom = sext i32 %1 to i64
+ %arrayidx = getelementptr inbounds [2 x i32], [2 x i32]* @staticconstvar, i64 0, i64 %idxprom
+ %2 = load i32, i32* %arrayidx, align 4
+ %add1 = add nsw i32 %add, %2
+ ret i32 %add1
+}
+
+define i32 @referenceglobals(i32 %i) #0 {
+entry:
+ %i.addr = alloca i32, align 4
+ store i32 %i, i32* %i.addr, align 4
+ call void @globalfunc1()
+ %0 = load i32, i32* @globalvar, align 4
+ ret i32 %0
+}
+
+define i32 @referencecommon(i32 %i) #0 {
+entry:
+ %i.addr = alloca i32, align 4
+ store i32 %i, i32* %i.addr, align 4
+ %0 = load i32, i32* @commonvar, align 4
+ ret i32 %0
+}
+
+define void @setfuncptr() #0 {
+entry:
+ store void ()* @staticfunc2, void ()** @P, align 8
+ ret void
+}
+
+define void @callfuncptr() #0 {
+entry:
+ %0 = load void ()*, void ()** @P, align 8
+ call void %0()
+ ret void
+}
+
+ at weakvar = weak global i32 1, align 4
+define weak void @weakfunc() #0 {
+entry:
+ ret void
+}
+
+define void @callweakfunc() #0 {
+entry:
+ call void @weakfunc()
+ ret void
+}
+
+define internal i32 @staticfunc() #0 {
+entry:
+ ret i32 1
+}
+
+define internal void @staticfunc2() #0 {
+entry:
+ ret void
+}
+
+
Added: llvm/trunk/test/Transforms/FunctionImport/funcimport.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionImport/funcimport.ll?rev=253954&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/FunctionImport/funcimport.ll (added)
+++ llvm/trunk/test/Transforms/FunctionImport/funcimport.ll Tue Nov 24 00:07:49 2015
@@ -0,0 +1,42 @@
+; Do setup work for all below tests: generate bitcode and combined index
+; RUN: llvm-as -function-summary %s -o %t.bc
+; RUN: llvm-as -function-summary %p/Inputs/funcimport.ll -o %t2.bc
+; RUN: llvm-lto -thinlto -o %t3 %t.bc %t2.bc
+
+; Do the import now
+; RUN: opt -function-import -summary-file %t3.thinlto.bc %s -S | FileCheck %s
+
+define i32 @main() #0 {
+entry:
+ call void (...) @weakalias()
+ call void (...) @analias()
+ %call = call i32 (...) @referencestatics()
+ %call1 = call i32 (...) @referenceglobals()
+ %call2 = call i32 (...) @referencecommon()
+ call void (...) @setfuncptr()
+ call void (...) @callfuncptr()
+ call void (...) @callweakfunc()
+ ret i32 0
+}
+
+; Won't import alias
+declare void @weakalias(...) #1
+declare void @analias(...) #1
+
+; CHECK-DAG: define available_externally i32 @referencestatics(i32 %i)
+declare i32 @referencestatics(...) #1
+
+; CHECK-DAG: define available_externally i32 @referenceglobals(i32 %i)
+declare i32 @referenceglobals(...) #1
+
+; CHECK-DAG: define available_externally i32 @referencecommon(i32 %i)
+declare i32 @referencecommon(...) #1
+
+; CHECK-DAG: define available_externally void @setfuncptr()
+declare void @setfuncptr(...) #1
+
+; CHECK-DAG: define available_externally void @callfuncptr()
+declare void @callfuncptr(...) #1
+
+; Won't import weak func
+declare void @callweakfunc(...) #1
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