mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-07-19 19:30:10 +00:00
1e43516dcf
* Add new RegisterOpt/RegisterAnalysis templates for registering passes that are to show up in opt or analyze * Register Analyses now * Change optimizations to use RegisterOpt instead of RegisterPass * Add support for different "PassType's" * Add new RegisterOpt/RegisterAnalysis templates for registering passes that are to show up in opt or analyze * Register Analyses now * Change optimizations to use RegisterOpt instead of RegisterPass * Remove getPassName implementations from various subclasses git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3112 91177308-0d34-0410-b5e6-96231b3b80d8
74 lines
2.6 KiB
C++
74 lines
2.6 KiB
C++
//===- ConstantMerge.cpp - Merge duplicate global constants -----------------=//
|
|
//
|
|
// This file defines the interface to a pass that merges duplicate global
|
|
// constants together into a single constant that is shared. This is useful
|
|
// because some passes (ie TraceValues) insert a lot of string constants into
|
|
// the program, regardless of whether or not they duplicate an existing string.
|
|
//
|
|
// Algorithm: ConstantMerge is designed to build up a map of available constants
|
|
// and elminate duplicates when it is initialized.
|
|
//
|
|
// The DynamicConstantMerge method is a superset of the ConstantMerge algorithm
|
|
// that checks for each function to see if constants have been added to the
|
|
// constant pool since it was last run... if so, it processes them.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Transforms/IPO.h"
|
|
#include "llvm/Module.h"
|
|
#include "llvm/Pass.h"
|
|
#include "Support/StatisticReporter.h"
|
|
|
|
namespace {
|
|
struct ConstantMerge : public Pass {
|
|
// run - For this pass, process all of the globals in the module,
|
|
// eliminating duplicate constants.
|
|
//
|
|
bool run(Module &M);
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.preservesCFG();
|
|
}
|
|
};
|
|
|
|
Statistic<> NumMerged("constmerge\t\t- Number of global constants merged");
|
|
RegisterOpt<ConstantMerge> X("constmerge","Merge Duplicate Global Constants");
|
|
}
|
|
|
|
Pass *createConstantMergePass() { return new ConstantMerge(); }
|
|
|
|
|
|
// ConstantMerge::run - Workhorse for the pass. This eliminates duplicate
|
|
// constants, starting at global ConstantNo, and adds vars to the map if they
|
|
// are new and unique.
|
|
//
|
|
bool ConstantMerge::run(Module &M) {
|
|
std::map<Constant*, GlobalVariable*> CMap;
|
|
bool MadeChanges = false;
|
|
|
|
for (Module::giterator GV = M.gbegin(), E = M.gend(); GV != E; ++GV)
|
|
if (GV->isConstant()) { // Only process constants
|
|
assert(GV->hasInitializer() && "Globals constants must have inits!");
|
|
Constant *Init = GV->getInitializer();
|
|
|
|
// Check to see if the initializer is already known...
|
|
std::map<Constant*, GlobalVariable*>::iterator I = CMap.find(Init);
|
|
|
|
if (I == CMap.end()) { // Nope, add it to the map
|
|
CMap.insert(I, std::make_pair(Init, GV));
|
|
} else { // Yup, this is a duplicate!
|
|
// Make all uses of the duplicate constant use the cannonical version...
|
|
GV->replaceAllUsesWith(I->second);
|
|
|
|
// Delete the global value from the module... and back up iterator to
|
|
// not skip the next global...
|
|
GV = --M.getGlobalList().erase(GV);
|
|
|
|
++NumMerged;
|
|
MadeChanges = true;
|
|
}
|
|
}
|
|
|
|
return MadeChanges;
|
|
}
|