mirror of
https://github.com/c64scene-ar/llvm-6502.git
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a92f696b74
* Renamed StatisticReporter.h/cpp to Statistic.h/cpp
* Broke constructor to take two const char * arguments instead of one, so
that indendation can be taken care of automatically.
* Sort the list by pass name when printing
* Make sure to print all statistics as a group, instead of randomly when
the statistics dtors are called.
* Updated ProgrammersManual with new semantics.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4002 91177308-0d34-0410-b5e6-96231b3b80d8
99 lines
3.2 KiB
C++
99 lines
3.2 KiB
C++
//===- DeadTypeElimination.cpp - Eliminate unused types for symbol table --===//
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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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#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/SymbolTable.h"
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#include "llvm/DerivedTypes.h"
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#include "Support/Statistic.h"
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using std::vector;
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namespace {
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struct DTE : public Pass {
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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 run(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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RegisterOpt<DTE> X("deadtypeelim", "Dead Type Elimination");
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Statistic<>
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NumKilled("deadtypeelim", "Number of unused typenames removed from symtab");
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}
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Pass *createDeadTypeEliminationPass() {
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return new DTE();
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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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// 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::run(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...
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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 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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//
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if (ShouldNukeSymtabEntry(*PI) ||
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!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();
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#endif
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++NumKilled;
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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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