mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-20 11:29:24 +00:00
Improve comments, no functionality changes
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16814 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
parent
a1c972df7d
commit
cf4d2a5699
@ -42,15 +42,45 @@ ModulePass *llvm::createGlobalOptimizerPass() { return new GlobalOpt(); }
|
||||
|
||||
/// GlobalStatus - As we analyze each global, keep track of some information
|
||||
/// about it. If we find out that the address of the global is taken, none of
|
||||
/// the other info will be accurate.
|
||||
/// this info will be accurate.
|
||||
struct GlobalStatus {
|
||||
/// isLoaded - True if the global is ever loaded. If the global isn't ever
|
||||
/// loaded it can be deleted.
|
||||
bool isLoaded;
|
||||
|
||||
/// StoredType - Keep track of what stores to the global look like.
|
||||
///
|
||||
enum StoredType {
|
||||
NotStored, isInitializerStored, isMallocStored, isStored
|
||||
/// NotStored - There is no store to this global. It can thus be marked
|
||||
/// constant.
|
||||
NotStored,
|
||||
|
||||
/// isInitializerStored - This global is stored to, but the only thing
|
||||
/// stored is the constant it was initialized with. This is only tracked
|
||||
/// for scalar globals.
|
||||
isInitializerStored,
|
||||
|
||||
/// isStoredOnce - This global is stored to, but only its initializer and
|
||||
/// one other value is ever stored to it. If this global isStoredOnce, we
|
||||
/// track the value stored to it in StoredOnceValue below. This is only
|
||||
/// tracked for scalar globals.
|
||||
isStoredOnce,
|
||||
|
||||
/// isStored - This global is stored to by multiple values or something else
|
||||
/// that we cannot track.
|
||||
isStored
|
||||
} StoredType;
|
||||
|
||||
/// StoredOnceValue - If only one value (besides the initializer constant) is
|
||||
/// ever stored to this global, keep track of what value it is.
|
||||
Value *StoredOnceValue;
|
||||
|
||||
/// isNotSuitableForSRA - Keep track of whether any SRA preventing users of
|
||||
/// the global exist. Such users include GEP instruction with variable
|
||||
/// indexes, and non-gep/load/store users like constant expr casts.
|
||||
bool isNotSuitableForSRA;
|
||||
|
||||
GlobalStatus() : isLoaded(false), StoredType(NotStored),
|
||||
GlobalStatus() : isLoaded(false), StoredType(NotStored), StoredOnceValue(0),
|
||||
isNotSuitableForSRA(false) {}
|
||||
};
|
||||
|
||||
@ -72,24 +102,29 @@ static bool AnalyzeGlobal(Value *V, GlobalStatus &GS,
|
||||
// Don't allow a store OF the address, only stores TO the address.
|
||||
if (SI->getOperand(0) == V) return true;
|
||||
|
||||
// If this store is just storing the initializer into a global (i.e. not
|
||||
// changing the value), ignore it. For now we just handle direct
|
||||
// stores, no stores to fields of aggregates.
|
||||
// If this is a direct store to the global (i.e., the global is a scalar
|
||||
// value, not an aggregate), keep more specific information about
|
||||
// stores.
|
||||
if (GS.StoredType != GlobalStatus::isStored)
|
||||
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(SI->getOperand(1))){
|
||||
if (SI->getOperand(0) == GV->getInitializer() &&
|
||||
GS.StoredType < GlobalStatus::isInitializerStored)
|
||||
if (SI->getOperand(0) == GV->getInitializer()) {
|
||||
if (GS.StoredType < GlobalStatus::isInitializerStored)
|
||||
GS.StoredType = GlobalStatus::isInitializerStored;
|
||||
else if (isa<MallocInst>(SI->getOperand(0)) &&
|
||||
GS.StoredType < GlobalStatus::isMallocStored)
|
||||
GS.StoredType = GlobalStatus::isMallocStored;
|
||||
else
|
||||
} else if (GS.StoredType < GlobalStatus::isStoredOnce) {
|
||||
GS.StoredType = GlobalStatus::isStoredOnce;
|
||||
GS.StoredOnceValue = SI->getOperand(0);
|
||||
} else if (GS.StoredType == GlobalStatus::isStoredOnce &&
|
||||
GS.StoredOnceValue == SI->getOperand(0)) {
|
||||
// noop.
|
||||
} else {
|
||||
GS.StoredType = GlobalStatus::isStored;
|
||||
}
|
||||
} else {
|
||||
GS.StoredType = GlobalStatus::isStored;
|
||||
}
|
||||
} else if (I->getOpcode() == Instruction::GetElementPtr) {
|
||||
if (AnalyzeGlobal(I, GS, PHIUsers)) return true;
|
||||
if (!GS.isNotSuitableForSRA)
|
||||
if (!GS.isNotSuitableForSRA)// Check to see if we have any variable idxs
|
||||
for (unsigned i = 1, e = I->getNumOperands(); i != e; ++i)
|
||||
if (!isa<Constant>(I->getOperand(i))) {
|
||||
GS.isNotSuitableForSRA = true;
|
||||
|
Loading…
Reference in New Issue
Block a user