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081c34b725
must be called in the pass's constructor. This function uses static dependency declarations to recursively initialize the pass's dependencies. Clients that only create passes through the createFooPass() APIs will require no changes. Clients that want to use the CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h before parsing commandline arguments. I have tested this with all standard configurations of clang and llvm-gcc on Darwin. It is possible that there are problems with the static dependencies that will only be visible with non-standard options. If you encounter any crash in pass registration/creation, please send the testcase to me directly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116820 91177308-0d34-0410-b5e6-96231b3b80d8
112 lines
3.5 KiB
C++
112 lines
3.5 KiB
C++
//===- DeadTypeElimination.cpp - Eliminate unused types for symbol table --===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass is used to cleanup the output of GCC. It eliminate names for types
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// that are unused in the entire translation unit, using the FindUsedTypes pass.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "deadtypeelim"
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#include "llvm/Transforms/IPO.h"
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#include "llvm/Analysis/FindUsedTypes.h"
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#include "llvm/Module.h"
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#include "llvm/TypeSymbolTable.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/ADT/Statistic.h"
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using namespace llvm;
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STATISTIC(NumKilled, "Number of unused typenames removed from symtab");
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namespace {
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struct DTE : public ModulePass {
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static char ID; // Pass identification, replacement for typeid
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DTE() : ModulePass(ID) {
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initializeDTEPass(*PassRegistry::getPassRegistry());
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}
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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 runOnModule(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>();
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}
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};
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}
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char DTE::ID = 0;
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INITIALIZE_PASS_BEGIN(DTE, "deadtypeelim", "Dead Type Elimination",
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false, false)
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INITIALIZE_PASS_DEPENDENCY(FindUsedTypes)
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INITIALIZE_PASS_END(DTE, "deadtypeelim", "Dead Type Elimination", false, false)
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ModulePass *llvm::createDeadTypeEliminationPass() {
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return new DTE();
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}
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// ShouldNukeSymtabEntry - 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 Type *Ty){
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// Nuke all names for primitive types!
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if (Ty->isPrimitiveType() || Ty->isIntegerTy())
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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>(Ty))
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if (PT->getElementType()->isPrimitiveType() ||
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PT->getElementType()->isIntegerTy())
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return true;
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return false;
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}
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// run - For this pass, it removes global symbol table entries for primitive
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// types. These are never used for linking in GCC and they make the output
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// uglier to look at, so we nuke them. Also eliminate types that are never used
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// in the entire program as indicated by FindUsedTypes.
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//
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bool DTE::runOnModule(Module &M) {
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bool Changed = false;
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TypeSymbolTable &ST = M.getTypeSymbolTable();
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std::set<const Type *> UsedTypes = getAnalysis<FindUsedTypes>().getTypes();
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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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TypeSymbolTable::iterator TI = ST.begin();
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TypeSymbolTable::iterator TE = ST.end();
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while ( TI != TE ) {
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// If this entry should be unconditionally removed, or if we detect that
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// the type is not used, remove it.
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const Type *RHS = TI->second;
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if (ShouldNukeSymtabEntry(RHS) || !UsedTypes.count(RHS)) {
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ST.remove(TI++);
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++NumKilled;
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Changed = true;
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} else {
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++TI;
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// We only need to leave one name for each type.
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UsedTypes.erase(RHS);
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}
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}
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return Changed;
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}
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// vim: sw=2
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