//===- DeadTypeElimination.cpp - Eliminate unused types for symbol table --===//
//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
// This pass is used to cleanup the output of GCC. It eliminate names for types
// that are unused in the entire translation unit, using the FindUsedTypes pass.
//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "deadtypeelim"
#include "llvm/Transforms/IPO.h"
#include "llvm/Analysis/FindUsedTypes.h"
#include "llvm/Module.h"
-#include "llvm/SymbolTable.h"
+#include "llvm/TypeSymbolTable.h"
#include "llvm/DerivedTypes.h"
-#include "Support/StatisticReporter.h"
+#include "llvm/ADT/Statistic.h"
+using namespace llvm;
-using std::vector;
+STATISTIC(NumKilled, "Number of unused typenames removed from symtab");
namespace {
- struct DTE : public Pass {
+ struct DTE : public ModulePass {
+ static char ID; // Pass identification, replacement for typeid
+ DTE() : ModulePass(ID) {}
+
// doPassInitialization - For this pass, it removes global symbol table
// entries for primitive types. These are never used for linking in GCC and
// they make the output uglier to look at, so we nuke them.
//
// Also, initialize instance variables.
//
- bool run(Module &M);
+ bool runOnModule(Module &M);
// getAnalysisUsage - This function needs FindUsedTypes to do its job...
//
AU.addRequired<FindUsedTypes>();
}
};
- RegisterOpt<DTE> X("deadtypeelim", "Dead Type Elimination");
- Statistic<> NumKilled("deadtypeelim\t- Number of unused typenames removed from symtab");
}
-Pass *createDeadTypeEliminationPass() {
+char DTE::ID = 0;
+INITIALIZE_PASS(DTE, "deadtypeelim", "Dead Type Elimination", false, false);
+
+ModulePass *llvm::createDeadTypeEliminationPass() {
return new DTE();
}
-
-// ShouldNukSymtabEntry - Return true if this module level symbol table entry
+// ShouldNukeSymtabEntry - Return true if this module level symbol table entry
// should be eliminated.
//
-static inline bool ShouldNukeSymtabEntry(const std::pair<std::string,Value*>&E){
+static inline bool ShouldNukeSymtabEntry(const Type *Ty){
// Nuke all names for primitive types!
- if (cast<Type>(E.second)->isPrimitiveType()) return true;
+ if (Ty->isPrimitiveType() || Ty->isIntegerTy())
+ return true;
// Nuke all pointers to primitive types as well...
- if (const PointerType *PT = dyn_cast<PointerType>(E.second))
- if (PT->getElementType()->isPrimitiveType()) return true;
+ if (const PointerType *PT = dyn_cast<PointerType>(Ty))
+ if (PT->getElementType()->isPrimitiveType() ||
+ PT->getElementType()->isIntegerTy())
+ return true;
return false;
}
// uglier to look at, so we nuke them. Also eliminate types that are never used
// in the entire program as indicated by FindUsedTypes.
//
-bool DTE::run(Module &M) {
+bool DTE::runOnModule(Module &M) {
bool Changed = false;
- if (SymbolTable *ST = M.getSymbolTable()) {
- const std::set<const Type *> &UsedTypes =
- getAnalysis<FindUsedTypes>().getTypes();
+ TypeSymbolTable &ST = M.getTypeSymbolTable();
+ std::set<const Type *> UsedTypes = getAnalysis<FindUsedTypes>().getTypes();
- // Check the symbol table for superfluous type entries...
- //
- // Grab the 'type' plane of the module symbol...
- SymbolTable::iterator STI = ST->find(Type::TypeTy);
- if (STI != ST->end()) {
- // Loop over all entries in the type plane...
- SymbolTable::VarMap &Plane = STI->second;
- for (SymbolTable::VarMap::iterator PI = Plane.begin(); PI != Plane.end();)
- if (ShouldNukeSymtabEntry(*PI)) { // Should we remove this entry?
-#if MAP_IS_NOT_BRAINDEAD
- PI = Plane.erase(PI); // STD C++ Map should support this!
-#else
- Plane.erase(PI); // Alas, GCC 2.95.3 doesn't *SIGH*
- PI = Plane.begin();
-#endif
- ++NumKilled;
- Changed = true;
- } else if (!UsedTypes.count(cast<Type>(PI->second))) {
-#if MAP_IS_NOT_BRAINDEAD
- PI = Plane.erase(PI); // STD C++ Map should support this!
-#else
- Plane.erase(PI); // Alas, GCC 2.95.3 doesn't *SIGH*
- PI = Plane.begin(); // N^2 algorithms are fun. :(
-#endif
- ++NumKilled;
- Changed = true;
- } else {
- ++PI;
- }
+ // Check the symbol table for superfluous type entries...
+ //
+ // Grab the 'type' plane of the module symbol...
+ TypeSymbolTable::iterator TI = ST.begin();
+ TypeSymbolTable::iterator TE = ST.end();
+ while ( TI != TE ) {
+ // If this entry should be unconditionally removed, or if we detect that
+ // the type is not used, remove it.
+ const Type *RHS = TI->second;
+ if (ShouldNukeSymtabEntry(RHS) || !UsedTypes.count(RHS)) {
+ ST.remove(TI++);
+ ++NumKilled;
+ Changed = true;
+ } else {
+ ++TI;
+ // We only need to leave one name for each type.
+ UsedTypes.erase(RHS);
}
}
return Changed;
}
+
+// vim: sw=2