| //===-- StripDeadPrototypes.cpp - Remove unused function declarations ----===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // 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.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/Pass.h" |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "strip-dead-prototypes" |
| |
| STATISTIC(NumDeadPrototypes, "Number of dead prototypes removed"); |
| |
| namespace { |
| |
| /// @brief Pass to remove unused function declarations. |
| class StripDeadPrototypesPass : public ModulePass { |
| public: |
| static char ID; // Pass identification, replacement for typeid |
| StripDeadPrototypesPass() : ModulePass(ID) { |
| initializeStripDeadPrototypesPassPass(*PassRegistry::getPassRegistry()); |
| } |
| bool runOnModule(Module &M) override; |
| }; |
| |
| } // end anonymous namespace |
| |
| char StripDeadPrototypesPass::ID = 0; |
| INITIALIZE_PASS(StripDeadPrototypesPass, "strip-dead-prototypes", |
| "Strip Unused Function Prototypes", false, false) |
| |
| bool StripDeadPrototypesPass::runOnModule(Module &M) { |
| bool MadeChange = false; |
| |
| // Erase dead function prototypes. |
| for (Module::iterator I = M.begin(), E = M.end(); I != E; ) { |
| Function *F = I++; |
| // Function must be a prototype and unused. |
| if (F->isDeclaration() && F->use_empty()) { |
| F->eraseFromParent(); |
| ++NumDeadPrototypes; |
| MadeChange = true; |
| } |
| } |
| |
| // Erase dead global var prototypes. |
| for (Module::global_iterator I = M.global_begin(), E = M.global_end(); |
| I != E; ) { |
| GlobalVariable *GV = I++; |
| // 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; |
| } |
| |
| ModulePass *llvm::createStripDeadPrototypesPass() { |
| return new StripDeadPrototypesPass(); |
| } |