1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
//===- StripSymbols.cpp - Strip symbols and debug info from a module ------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements stripping symbols out of symbol tables.
//
// Specifically, this allows you to strip all of the symbols out of:
// * All functions in a module
// * All non-essential symbols in a module (all function symbols + all module
// scope symbols)
// * Debug information.
//
// Notice that:
// * This pass makes code much less readable, so it should only be used in
// situations where the 'strip' utility would be used (such as reducing
// code size, and making it harder to reverse engineer code).
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/SymbolTable.h"
using namespace llvm;
namespace {
class StripSymbols : public ModulePass {
bool OnlyDebugInfo;
public:
StripSymbols(bool ODI = false) : OnlyDebugInfo(ODI) {}
virtual bool runOnModule(Module &M);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
};
RegisterOpt<StripSymbols> X("strip", "Strip all symbols from a module");
}
ModulePass *llvm::createStripSymbolsPass(bool OnlyDebugInfo) {
return new StripSymbols(OnlyDebugInfo);
}
static void RemoveDeadConstant(Constant *C) {
assert(C->use_empty() && "Constant is not dead!");
std::vector<Constant*> Operands;
for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
if (isa<DerivedType>(C->getOperand(i)->getType()) &&
C->getOperand(i)->hasOneUse())
Operands.push_back(C->getOperand(i));
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
if (!GV->hasInternalLinkage()) return; // Don't delete non static globals.
GV->eraseFromParent();
}
else if (!isa<Function>(C))
C->destroyConstant();
// If the constant referenced anything, see if we can delete it as well.
while (!Operands.empty()) {
RemoveDeadConstant(Operands.back());
Operands.pop_back();
}
}
bool StripSymbols::runOnModule(Module &M) {
// If we're not just stripping debug info, strip all symbols from the
// functions and the names from any internal globals.
if (!OnlyDebugInfo) {
for (Module::global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I)
if (I->hasInternalLinkage())
I->setName(""); // Internal symbols can't participate in linkage
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
if (I->hasInternalLinkage())
I->setName(""); // Internal symbols can't participate in linkage
I->getSymbolTable().strip();
}
}
// Strip debug info in the module if it exists. To do this, we remove
// llvm.dbg.func.start, llvm.dbg.stoppoint, and llvm.dbg.region.end calls, and
// any globals they point to if now dead.
Function *FuncStart = M.getNamedFunction("llvm.dbg.func.start");
Function *StopPoint = M.getNamedFunction("llvm.dbg.stoppoint");
Function *RegionEnd = M.getNamedFunction("llvm.dbg.region.end");
if (!FuncStart && !StopPoint && !RegionEnd)
return true;
std::vector<GlobalVariable*> DeadGlobals;
// Remove all of the calls to the debugger intrinsics, and remove them from
// the module.
if (FuncStart) {
Value *RV = UndefValue::get(FuncStart->getFunctionType()->getReturnType());
while (!FuncStart->use_empty()) {
CallInst *CI = cast<CallInst>(FuncStart->use_back());
Value *Arg = CI->getOperand(1);
CI->replaceAllUsesWith(RV);
CI->eraseFromParent();
if (Arg->use_empty())
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
DeadGlobals.push_back(GV);
}
FuncStart->eraseFromParent();
}
if (StopPoint) {
Value *RV = UndefValue::get(StopPoint->getFunctionType()->getReturnType());
while (!StopPoint->use_empty()) {
CallInst *CI = cast<CallInst>(StopPoint->use_back());
Value *Arg = CI->getOperand(4);
CI->replaceAllUsesWith(RV);
CI->eraseFromParent();
if (Arg->use_empty())
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
DeadGlobals.push_back(GV);
}
StopPoint->eraseFromParent();
}
if (RegionEnd) {
Value *RV = UndefValue::get(RegionEnd->getFunctionType()->getReturnType());
while (!RegionEnd->use_empty()) {
CallInst *CI = cast<CallInst>(RegionEnd->use_back());
CI->replaceAllUsesWith(RV);
CI->eraseFromParent();
}
RegionEnd->eraseFromParent();
}
// Finally, delete any internal globals that were only used by the debugger
// intrinsics.
while (!DeadGlobals.empty()) {
GlobalVariable *GV = DeadGlobals.back();
DeadGlobals.pop_back();
if (GV->hasInternalLinkage())
RemoveDeadConstant(GV);
}
return true;
}
|
