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"
22 #include "llvm/Support/Compiler.h"
25 STATISTIC(NumDeadPrototypes, "Number of dead prototypes removed");
29 /// @brief Pass to remove unused function declarations.
30 class VISIBILITY_HIDDEN StripDeadPrototypesPass : public ModulePass {
32 static char ID; // Pass identification, replacement for typeid
33 StripDeadPrototypesPass() : ModulePass(&ID) { }
34 virtual bool runOnModule(Module &M);
37 } // end anonymous namespace
39 char StripDeadPrototypesPass::ID = 0;
40 static RegisterPass<StripDeadPrototypesPass>
41 X("strip-dead-prototypes", "Strip Unused Function Prototypes");
43 bool StripDeadPrototypesPass::runOnModule(Module &M) {
44 bool MadeChange = false;
46 // Erase dead function prototypes.
47 for (Module::iterator I = M.begin(), E = M.end(); I != E; ) {
49 // Function must be a prototype and unused.
50 if (F->isDeclaration() && F->use_empty()) {
57 // Erase dead global var prototypes.
58 for (Module::global_iterator I = M.global_begin(), E = M.global_end();
60 GlobalVariable *GV = I++;
61 // Global must be a prototype and unused.
62 if (GV->isDeclaration() && GV->use_empty())
63 GV->eraseFromParent();
66 // Return an indication of whether we changed anything or not.
70 ModulePass *llvm::createStripDeadPrototypesPass() {
71 return new StripDeadPrototypesPass();