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* Register Pass git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3011 91177308-0d34-0410-b5e6-96231b3b80d8
140 lines
4.6 KiB
C++
140 lines
4.6 KiB
C++
//===- CleanupGCCOutput.cpp - Cleanup GCC Output --------------------------===//
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//
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// This pass is used to cleanup the output of GCC. GCC's output is
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// unneccessarily gross for a couple of reasons. This pass does the following
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// things to try to clean it up:
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//
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// * Eliminate names for GCC types that we know can't be needed by the user.
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// * Eliminate names for types that are unused in the entire translation unit
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// * Fix various problems that we might have in PHI nodes and casts
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//
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// Note: This code produces dead declarations, it is a good idea to run DCE
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// after this pass.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/CleanupGCCOutput.h"
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#include "llvm/Analysis/FindUsedTypes.h"
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#include "llvm/Module.h"
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#include "llvm/SymbolTable.h"
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#include "llvm/DerivedTypes.h"
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#include "Support/StatisticReporter.h"
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static Statistic<> NumTypeSymtabEntriesKilled("cleangcc\t- Number of unused typenames removed from symtab");
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using std::vector;
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namespace {
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struct CleanupGCCOutput : public FunctionPass {
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// doPassInitialization - For this pass, it removes global symbol table
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// entries for primitive types. These are never used for linking in GCC and
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// they make the output uglier to look at, so we nuke them.
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//
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// Also, initialize instance variables.
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//
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bool doInitialization(Module &M);
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// FIXME:
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// FIXME: This FunctionPass should be a PASS!
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// FIXME:
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bool runOnFunction(Function &F) { return false; }
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// doPassFinalization - Strip out type names that are unused by the program
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bool doFinalization(Module &M);
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// getAnalysisUsage - This function needs FindUsedTypes to do its job...
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//
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired(FindUsedTypes::ID);
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}
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};
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RegisterPass<CleanupGCCOutput> X("cleangcc", "Cleanup GCC Output");
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}
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Pass *createCleanupGCCOutputPass() {
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return new CleanupGCCOutput();
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}
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// ShouldNukSymtabEntry - Return true if this module level symbol table entry
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// should be eliminated.
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//
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static inline bool ShouldNukeSymtabEntry(const std::pair<std::string,Value*>&E){
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// Nuke all names for primitive types!
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if (cast<Type>(E.second)->isPrimitiveType()) return true;
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// Nuke all pointers to primitive types as well...
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if (const PointerType *PT = dyn_cast<PointerType>(E.second))
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if (PT->getElementType()->isPrimitiveType()) return true;
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return false;
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}
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// doInitialization - For this pass, it removes global symbol table
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// entries for primitive types. These are never used for linking in GCC and
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// they make the output uglier to look at, so we nuke them.
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//
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bool CleanupGCCOutput::doInitialization(Module &M) {
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bool Changed = false;
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if (SymbolTable *ST = M.getSymbolTable()) {
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// Check the symbol table for superfluous type entries...
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//
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// Grab the 'type' plane of the module symbol...
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SymbolTable::iterator STI = ST->find(Type::TypeTy);
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if (STI != ST->end()) {
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// Loop over all entries in the type plane...
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SymbolTable::VarMap &Plane = STI->second;
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for (SymbolTable::VarMap::iterator PI = Plane.begin(); PI != Plane.end();)
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if (ShouldNukeSymtabEntry(*PI)) { // Should we remove this entry?
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#if MAP_IS_NOT_BRAINDEAD
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PI = Plane.erase(PI); // STD C++ Map should support this!
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#else
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Plane.erase(PI); // Alas, GCC 2.95.3 doesn't *SIGH*
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PI = Plane.begin();
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#endif
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++NumTypeSymtabEntriesKilled;
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Changed = true;
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} else {
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++PI;
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}
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}
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}
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return Changed;
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}
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bool CleanupGCCOutput::doFinalization(Module &M) {
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bool Changed = false;
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if (SymbolTable *ST = M.getSymbolTable()) {
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const std::set<const Type *> &UsedTypes =
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getAnalysis<FindUsedTypes>().getTypes();
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// Check the symbol table for superfluous type entries that aren't used in
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// the program
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//
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// Grab the 'type' plane of the module symbol...
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SymbolTable::iterator STI = ST->find(Type::TypeTy);
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if (STI != ST->end()) {
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// Loop over all entries in the type plane...
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SymbolTable::VarMap &Plane = STI->second;
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for (SymbolTable::VarMap::iterator PI = Plane.begin(); PI != Plane.end();)
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if (!UsedTypes.count(cast<Type>(PI->second))) {
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#if MAP_IS_NOT_BRAINDEAD
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PI = Plane.erase(PI); // STD C++ Map should support this!
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#else
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Plane.erase(PI); // Alas, GCC 2.95.3 doesn't *SIGH*
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PI = Plane.begin(); // N^2 algorithms are fun. :(
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#endif
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Changed = true;
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} else {
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++PI;
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}
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}
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}
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return Changed;
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}
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