RPCSX/llvm
1
0
Fork 0
mirror of https://github.com/RPCSX/llvm.git synced 2024-11-29 14:40:25 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Add an early bailout to IsValueFullyAvailableInBlock from deeply nested blocks.

Browse Source 
The limit is set to an arbitrary 1000 recursion depth to avoid stack overflow
issues. <rdar://problem/11286839>.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155722 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Mon P Wang 2012-04-27 18:09:28 +00:00
parent 03e091f0b5
commit 5dde20bfac
1 changed files with 12 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
lib/Transforms/Scalar/GVN.cpp
View File

@ -59,6 +59,11 @@ static cl::opt<bool> EnablePRE("enable-pre",
cl::init(true), cl::Hidden);
static cl::opt<bool> EnableLoadPRE("enable-load-pre", cl::init(true));
// Maximum allowed recursion depth.
static cl::opt<int>
MaxRecurseDepth("max-recurse-depth", cl::Hidden, cl::init(1000), cl::ZeroOrMore,
cl::desc("Max recurse depth (default = 1000)"));
//===----------------------------------------------------------------------===//
// ValueTable Class
//===----------------------------------------------------------------------===//
@ -647,7 +652,11 @@ void GVN::dump(DenseMap<uint32_t, Value*>& d) {
/// 3) we are speculating for this block and have used that to speculate for
/// other blocks.
static bool IsValueFullyAvailableInBlock(BasicBlock *BB,
DenseMap<BasicBlock*, char> &FullyAvailableBlocks) {
DenseMap<BasicBlock*, char> &FullyAvailableBlocks,
uint32_t RecurseDepth) {
if (RecurseDepth > MaxRecurseDepth)
return false;
// Optimistically assume that the block is fully available and check to see
// if we already know about this block in one lookup.
std::pair<DenseMap<BasicBlock*, char>::iterator, char> IV =
@ -673,7 +682,7 @@ static bool IsValueFullyAvailableInBlock(BasicBlock *BB,
// If the value isn't fully available in one of our predecessors, then it
// isn't fully available in this block either. Undo our previous
// optimistic assumption and bail out.
if (!IsValueFullyAvailableInBlock(*PI, FullyAvailableBlocks))
if (!IsValueFullyAvailableInBlock(*PI, FullyAvailableBlocks,RecurseDepth+1))
goto SpeculationFailure;
return true;
@ -1570,7 +1579,7 @@ bool GVN::processNonLocalLoad(LoadInst *LI) {
for (pred_iterator PI = pred_begin(LoadBB), E = pred_end(LoadBB);
PI != E; ++PI) {
BasicBlock *Pred = *PI;
if (IsValueFullyAvailableInBlock(Pred, FullyAvailableBlocks)) {
if (IsValueFullyAvailableInBlock(Pred, FullyAvailableBlocks, 0)) {
continue;
}
PredLoads[Pred] = 0;