1 //===-- StripDeadPrototypes.cpp - Remove unused function declarations ----===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass loops over all of the functions in the input module, looking for
11 // dead declarations and removes them. Dead declarations are declarations of
12 // functions for which no implementation is available (i.e., declarations for
13 // unused library functions).
15 //===----------------------------------------------------------------------===//
17 #define DEBUG_TYPE "strip-dead-prototypes"
18 #include "llvm/Transforms/IPO.h"
19 #include "llvm/Pass.h"
20 #include "llvm/Module.h"
21 #include "llvm/ADT/Statistic.h"
24 STATISTIC(NumDeadPrototypes, "Number of dead prototypes removed");
28 /// @brief Pass to remove unused function declarations.
29 class StripDeadPrototypesPass : public ModulePass {
31 static char ID; // Pass identification, replacement for typeid
32 StripDeadPrototypesPass() : ModulePass(&ID) { }
33 virtual bool runOnModule(Module &M);
36 } // end anonymous namespace
38 char StripDeadPrototypesPass::ID = 0;
39 static RegisterPass<StripDeadPrototypesPass>
40 X("strip-dead-prototypes", "Strip Unused Function Prototypes");
42 bool StripDeadPrototypesPass::runOnModule(Module &M) {
43 bool MadeChange = false;
45 // Erase dead function prototypes.
46 for (Module::iterator I = M.begin(), E = M.end(); I != E; ) {
48 // Function must be a prototype and unused.
49 if (F->isDeclaration() && F->use_empty()) {
56 // Erase dead global var prototypes.
57 for (Module::global_iterator I = M.global_begin(), E = M.global_end();
59 GlobalVariable *GV = I++;
60 // Global must be a prototype and unused.
61 if (GV->isDeclaration() && GV->use_empty())
62 GV->eraseFromParent();
65 // Return an indication of whether we changed anything or not.
69 ModulePass *llvm::createStripDeadPrototypesPass() {
70 return new StripDeadPrototypesPass();