144 lines · cpp
1//===- ForceFunctionAttrs.cpp - Force function attrs for debugging --------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "llvm/Transforms/IPO/ForceFunctionAttrs.h"10#include "llvm/IR/Function.h"11#include "llvm/IR/Module.h"12#include "llvm/Support/CommandLine.h"13#include "llvm/Support/Debug.h"14#include "llvm/Support/LineIterator.h"15#include "llvm/Support/MemoryBuffer.h"16#include "llvm/Support/raw_ostream.h"17using namespace llvm;18 19#define DEBUG_TYPE "forceattrs"20 21static cl::list<std::string> ForceAttributes(22 "force-attribute", cl::Hidden,23 cl::desc(24 "Add an attribute to a function. This can be a "25 "pair of 'function-name:attribute-name', to apply an attribute to a "26 "specific function. For "27 "example -force-attribute=foo:noinline. Specifying only an attribute "28 "will apply the attribute to every function in the module. This "29 "option can be specified multiple times."));30 31static cl::list<std::string> ForceRemoveAttributes(32 "force-remove-attribute", cl::Hidden,33 cl::desc("Remove an attribute from a function. This can be a "34 "pair of 'function-name:attribute-name' to remove an attribute "35 "from a specific function. For "36 "example -force-remove-attribute=foo:noinline. Specifying only an "37 "attribute will remove the attribute from all functions in the "38 "module. This "39 "option can be specified multiple times."));40 41static cl::opt<std::string> CSVFilePath(42 "forceattrs-csv-path", cl::Hidden,43 cl::desc(44 "Path to CSV file containing lines of function names and attributes to "45 "add to them in the form of `f1,attr1` or `f2,attr2=str`."));46 47/// If F has any forced attributes given on the command line, add them.48/// If F has any forced remove attributes given on the command line, remove49/// them. When both force and force-remove are given to a function, the latter50/// takes precedence.51static void forceAttributes(Function &F) {52 auto ParseFunctionAndAttr = [&](StringRef S) {53 StringRef AttributeText;54 if (S.contains(':')) {55 auto KV = StringRef(S).split(':');56 if (KV.first != F.getName())57 return Attribute::None;58 AttributeText = KV.second;59 } else {60 AttributeText = S;61 }62 auto Kind = Attribute::getAttrKindFromName(AttributeText);63 if (Kind == Attribute::None || !Attribute::canUseAsFnAttr(Kind)) {64 LLVM_DEBUG(dbgs() << "ForcedAttribute: " << AttributeText65 << " unknown or not a function attribute!\n");66 }67 return Kind;68 };69 70 for (const auto &S : ForceAttributes) {71 auto Kind = ParseFunctionAndAttr(S);72 if (Kind == Attribute::None || F.hasFnAttribute(Kind))73 continue;74 F.addFnAttr(Kind);75 }76 77 for (const auto &S : ForceRemoveAttributes) {78 auto Kind = ParseFunctionAndAttr(S);79 if (Kind == Attribute::None || !F.hasFnAttribute(Kind))80 continue;81 F.removeFnAttr(Kind);82 }83}84 85static bool hasForceAttributes() {86 return !ForceAttributes.empty() || !ForceRemoveAttributes.empty();87}88 89PreservedAnalyses ForceFunctionAttrsPass::run(Module &M,90 ModuleAnalysisManager &) {91 bool Changed = false;92 if (!CSVFilePath.empty()) {93 auto BufferOrError = MemoryBuffer::getFileOrSTDIN(CSVFilePath);94 if (!BufferOrError) {95 std::error_code EC = BufferOrError.getError();96 M.getContext().emitError("cannot open CSV file: " + EC.message());97 return PreservedAnalyses::all();98 }99 100 StringRef Buffer = BufferOrError.get()->getBuffer();101 auto MemoryBuffer = MemoryBuffer::getMemBuffer(Buffer);102 line_iterator It(*MemoryBuffer);103 for (; !It.is_at_end(); ++It) {104 auto SplitPair = It->split(',');105 if (SplitPair.second.empty())106 continue;107 Function *Func = M.getFunction(SplitPair.first);108 if (Func) {109 if (Func->isDeclaration())110 continue;111 auto SecondSplitPair = SplitPair.second.split('=');112 if (!SecondSplitPair.second.empty()) {113 Func->addFnAttr(SecondSplitPair.first, SecondSplitPair.second);114 Changed = true;115 } else {116 auto AttrKind = Attribute::getAttrKindFromName(SplitPair.second);117 if (AttrKind != Attribute::None &&118 Attribute::canUseAsFnAttr(AttrKind)) {119 // TODO: There could be string attributes without a value, we should120 // support those, too.121 Func->addFnAttr(AttrKind);122 Changed = true;123 } else124 errs() << "Cannot add " << SplitPair.second125 << " as an attribute name.\n";126 }127 } else {128 errs() << "Function in CSV file at line " << It.line_number()129 << " does not exist.\n";130 // TODO: `report_fatal_error at end of pass for missing functions.131 continue;132 }133 }134 }135 if (hasForceAttributes()) {136 for (Function &F : M.functions())137 forceAttributes(F);138 Changed = true;139 }140 // Just conservatively invalidate analyses if we've made any changes, this141 // isn't likely to be important.142 return Changed ? PreservedAnalyses::none() : PreservedAnalyses::all();143}144