| //===-- StripDeadPrototypes.cpp - Remove unused function declarations ----===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This pass loops over all of the functions in the input module, looking for |
| // dead declarations and removes them. Dead declarations are declarations of |
| // functions for which no implementation is available (i.e., declarations for |
| // unused library functions). |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Transforms/IPO/StripDeadPrototypes.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/InitializePasses.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Transforms/IPO.h" |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "strip-dead-prototypes" |
| |
| STATISTIC(NumDeadPrototypes, "Number of dead prototypes removed"); |
| |
| static bool stripDeadPrototypes(Module &M) { |
| bool MadeChange = false; |
| |
| // Erase dead function prototypes. |
| for (Function &F : llvm::make_early_inc_range(M)) { |
| // Function must be a prototype and unused. |
| if (F.isDeclaration() && F.use_empty()) { |
| F.eraseFromParent(); |
| ++NumDeadPrototypes; |
| MadeChange = true; |
| } |
| } |
| |
| // Erase dead global var prototypes. |
| for (GlobalVariable &GV : llvm::make_early_inc_range(M.globals())) { |
| // Global must be a prototype and unused. |
| if (GV.isDeclaration() && GV.use_empty()) |
| GV.eraseFromParent(); |
| } |
| |
| // Return an indication of whether we changed anything or not. |
| return MadeChange; |
| } |
| |
| PreservedAnalyses StripDeadPrototypesPass::run(Module &M, |
| ModuleAnalysisManager &) { |
| if (stripDeadPrototypes(M)) |
| return PreservedAnalyses::none(); |
| return PreservedAnalyses::all(); |
| } |
| |
| namespace { |
| |
| class StripDeadPrototypesLegacyPass : public ModulePass { |
| public: |
| static char ID; // Pass identification, replacement for typeid |
| StripDeadPrototypesLegacyPass() : ModulePass(ID) { |
| initializeStripDeadPrototypesLegacyPassPass( |
| *PassRegistry::getPassRegistry()); |
| } |
| bool runOnModule(Module &M) override { |
| if (skipModule(M)) |
| return false; |
| |
| return stripDeadPrototypes(M); |
| } |
| }; |
| |
| } // end anonymous namespace |
| |
| char StripDeadPrototypesLegacyPass::ID = 0; |
| INITIALIZE_PASS(StripDeadPrototypesLegacyPass, "strip-dead-prototypes", |
| "Strip Unused Function Prototypes", false, false) |
| |
| ModulePass *llvm::createStripDeadPrototypesPass() { |
| return new StripDeadPrototypesLegacyPass(); |
| } |