llvm-6502/lib/Transforms/Scalar/SymbolStripping.cpp
Chris Lattner 2cacc0a306 Update obsolete comments
Fix iterator invalidation problems which was causing -mstrip to miss some
entries, and read free'd memory.  This shrinks the symbol table of 254.gap
from 333 to 284 bytes!  :)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10751 91177308-0d34-0410-b5e6-96231b3b80d8
2004-01-10 21:36:49 +00:00

86 lines
2.8 KiB
C++

//===- SymbolStripping.cpp - Strip symbols for functions and modules ------===//
//
// 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)
//
// 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/Scalar.h"
#include "llvm/Module.h"
#include "llvm/SymbolTable.h"
#include "llvm/Pass.h"
using namespace llvm;
static bool StripSymbolTable(SymbolTable &SymTab) {
bool RemovedSymbol = false;
for (SymbolTable::iterator I = SymTab.begin(); I != SymTab.end();) {
// Removing items from the plane can cause the plane itself to get deleted.
// If this happens, make sure we incremented our plane iterator already!
std::map<const std::string, Value *> &Plane = (I++)->second;
SymbolTable::type_iterator B = Plane.begin(), Bend = Plane.end();
while (B != Bend) { // Found nonempty type plane!
Value *V = B->second;
if (isa<Constant>(V) || isa<Type>(V)) {
SymTab.type_remove(B++);
RemovedSymbol = true;
} else {
++B;
if (!isa<GlobalValue>(V) || cast<GlobalValue>(V)->hasInternalLinkage()){
// Set name to "", removing from symbol table!
V->setName("", &SymTab);
RemovedSymbol = true;
}
}
}
}
return RemovedSymbol;
}
namespace {
struct SymbolStripping : public FunctionPass {
virtual bool runOnFunction(Function &F) {
return StripSymbolTable(F.getSymbolTable());
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
};
RegisterOpt<SymbolStripping> X("strip", "Strip symbols from functions");
struct FullSymbolStripping : public SymbolStripping {
virtual bool doInitialization(Module &M) {
return StripSymbolTable(M.getSymbolTable());
}
};
RegisterOpt<FullSymbolStripping> Y("mstrip",
"Strip symbols from module and functions");
}
Pass *llvm::createSymbolStrippingPass() {
return new SymbolStripping();
}
Pass *llvm::createFullSymbolStrippingPass() {
return new FullSymbolStripping();
}