6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-06-23 17:24:48 +00:00
Code Issues Projects Releases Wiki Activity

Match semantics of PointerMayBeCapturedBefore to its name by default

Browse Source 
As it turns out, the capture tracker named CaptureBefore used by AA, and now
available via the PointerMayBeCapturedBefore function, would have been
more-aptly named CapturedBeforeOrAt, because it considers captures at the
instruction provided. This is not always what one wants, and it is difficult to
get the strictly-before behavior given only the current interface. This adds an
additional parameter which controls whether or not you want to include
captures at the provided instruction. The default is not to include the
instruction provided, so that 'Before' matches its name.

No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213582 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel
2014-07-21 21:30:22 +00:00
parent 529165298e
commit 9da65a8644
3 changed files with 17 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
lib/Analysis/CaptureTracking.cpp
View File

@ -57,14 +57,18 @@ namespace {
/// Only support the case where the Value is defined in the same basic block
/// as the given instruction and the use.
struct CapturesBefore : public CaptureTracker {
CapturesBefore(bool ReturnCaptures, const Instruction *I, DominatorTree *DT)
CapturesBefore(bool ReturnCaptures, const Instruction *I, DominatorTree *DT,
bool IncludeI)
: BeforeHere(I), DT(DT), ReturnCaptures(ReturnCaptures),
Captured(false) {}
IncludeI(IncludeI), Captured(false) {}
void tooManyUses() override { Captured = true; }
bool shouldExplore(const Use *U) override {
Instruction *I = cast<Instruction>(U->getUser());
if (BeforeHere == I && !IncludeI)
return false;
BasicBlock *BB = I->getParent();
// We explore this usage only if the usage can reach "BeforeHere".
// If use is not reachable from entry, there is no need to explore.
@ -84,6 +88,9 @@ namespace {
return false;
Instruction *I = cast<Instruction>(U->getUser());
if (BeforeHere == I && !IncludeI)
return false;
BasicBlock *BB = I->getParent();
// Same logic as in shouldExplore.
if (BeforeHere != I && !DT->isReachableFromEntry(BB))
@ -99,6 +106,7 @@ namespace {
DominatorTree *DT;
bool ReturnCaptures;
bool IncludeI;
bool Captured;
};
@ -138,7 +146,7 @@ bool llvm::PointerMayBeCaptured(const Value *V,
/// or not.
bool llvm::PointerMayBeCapturedBefore(const Value *V, bool ReturnCaptures,
bool StoreCaptures, const Instruction *I,
DominatorTree *DT) {
DominatorTree *DT, bool IncludeI) {
assert(!isa<GlobalValue>(V) &&
"It doesn't make sense to ask whether a global is captured.");
@ -148,7 +156,7 @@ bool llvm::PointerMayBeCapturedBefore(const Value *V, bool ReturnCaptures,
// TODO: See comment in PointerMayBeCaptured regarding what could be done
// with StoreCaptures.
CapturesBefore CB(ReturnCaptures, I, DT);
CapturesBefore CB(ReturnCaptures, I, DT, IncludeI);
PointerMayBeCaptured(V, &CB);
return CB.Captured;
}