LLVM 19.0.0git
StripDeadPrototypes.cpp
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1//===-- StripDeadPrototypes.cpp - Remove unused function declarations ----===//
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-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This pass loops over all of the functions in the input module, looking for
10// dead declarations and removes them. Dead declarations are declarations of
11// functions for which no implementation is available (i.e., declarations for
12// unused library functions).
13//
14//===----------------------------------------------------------------------===//
15
17#include "llvm/ADT/Statistic.h"
18#include "llvm/IR/Module.h"
19#include "llvm/Transforms/IPO.h"
20
21using namespace llvm;
22
23#define DEBUG_TYPE "strip-dead-prototypes"
24
25STATISTIC(NumDeadPrototypes, "Number of dead prototypes removed");
26
27static bool stripDeadPrototypes(Module &M) {
28 bool MadeChange = false;
29
30 // Erase dead function prototypes.
32 // Function must be a prototype and unused.
33 if (F.isDeclaration() && F.use_empty()) {
34 F.eraseFromParent();
35 ++NumDeadPrototypes;
36 MadeChange = true;
37 }
38 }
39
40 // Erase dead global var prototypes.
41 for (GlobalVariable &GV : llvm::make_early_inc_range(M.globals())) {
42 // Global must be a prototype and unused.
43 if (GV.isDeclaration() && GV.use_empty())
44 GV.eraseFromParent();
45 }
46
47 // Return an indication of whether we changed anything or not.
48 return MadeChange;
49}
50
56}
#define F(x, y, z)
Definition: MD5.cpp:55
Module.h This file contains the declarations for the Module class.
This file defines the 'Statistic' class, which is designed to be an easy way to expose various metric...
#define STATISTIC(VARNAME, DESC)
Definition: Statistic.h:167
static bool stripDeadPrototypes(Module &M)
A container for analyses that lazily runs them and caches their results.
Definition: PassManager.h:348
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:65
A set of analyses that are preserved following a run of a transformation pass.
Definition: Analysis.h:109
static PreservedAnalyses none()
Convenience factory function for the empty preserved set.
Definition: Analysis.h:112
static PreservedAnalyses all()
Construct a special preserved set that preserves all passes.
Definition: Analysis.h:115
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
iterator_range< early_inc_iterator_impl< detail::IterOfRange< RangeT > > > make_early_inc_range(RangeT &&Range)
Make a range that does early increment to allow mutation of the underlying range without disrupting i...
Definition: STLExtras.h:665
PreservedAnalyses run(Module &M, ModuleAnalysisManager &)