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Rename the flag which protects from escaped allocas, which may come from bugs in user code or in the compiler. Also, dont assert if the protection is not enabled.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163807 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nadav Rotem
2012-09-13 15:46:30 +00:00
parent af40a5be77
commit 18e2c29094
1 changed files with 12 additions and 5 deletions
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17
lib/CodeGen/StackColoring.cpp
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@@ -62,10 +62,15 @@ DisableColoring("no-stack-coloring",
cl::init(false), cl::Hidden, cl::init(false), cl::Hidden,
cl::desc("Disable stack coloring")); cl::desc("Disable stack coloring"));
/// The user may write code that uses allocas outside of the declared lifetime
/// zone. This can happen when the user returns a reference to a local
/// data-structure. We can detect these cases and decide not to optimize the
/// code. If this flag is enabled, we try to save the user.
static cl::opt<bool> static cl::opt<bool>
CheckEscapedAllocas("stack-coloring-check-escaped", ProtectFromEscapedAllocas("protect-from-escaped-allocas",
cl::init(true), cl::Hidden, cl::init(true), cl::Hidden,
cl::desc("Look for allocas which escaped the lifetime region")); cl::desc("Do not optimize lifetime zones that are broken"));
STATISTIC(NumMarkerSeen, "Number of lifetime markers found."); STATISTIC(NumMarkerSeen, "Number of lifetime markers found.");
STATISTIC(StackSpaceSaved, "Number of bytes saved due to merging slots."); STATISTIC(StackSpaceSaved, "Number of bytes saved due to merging slots.");
@@ -536,13 +541,15 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
// In a debug build, check that the instruction that we are modifying is // In a debug build, check that the instruction that we are modifying is
// inside the expected live range. If the instruction is not inside // inside the expected live range. If the instruction is not inside
// the calculated range then it means that the alloca usage moved // the calculated range then it means that the alloca usage moved
// outside of the lifetime markers. // outside of the lifetime markers, or that the user has a bug.
// NOTE: Alloca address calculations which happen outside the lifetime // NOTE: Alloca address calculations which happen outside the lifetime
// zone are are okay, despite the fact that we don't have a good way // zone are are okay, despite the fact that we don't have a good way
// for validating all of the usages of the calculation. // for validating all of the usages of the calculation.
#ifndef NDEBUG #ifndef NDEBUG
bool TouchesMemory = I->mayLoad() || I->mayStore(); bool TouchesMemory = I->mayLoad() || I->mayStore();
if (!I->isDebugValue() && TouchesMemory) { // If we *don't* protect the user from escaped allocas, don't bother
// validating the instructions.
if (!I->isDebugValue() && TouchesMemory && ProtectFromEscapedAllocas) {
SlotIndex Index = Indexes->getInstructionIndex(I); SlotIndex Index = Indexes->getInstructionIndex(I);
LiveInterval *Interval = Intervals[FromSlot]; LiveInterval *Interval = Intervals[FromSlot];
assert(Interval->find(Index) != Interval->end() && assert(Interval->find(Index) != Interval->end() &&
@@ -685,7 +692,7 @@ bool StackColoring::runOnMachineFunction(MachineFunction &Func) {
// Search for allocas which are used outside of the declared lifetime // Search for allocas which are used outside of the declared lifetime
// markers. // markers.
if (CheckEscapedAllocas) if (ProtectFromEscapedAllocas)
removeInvalidSlotRanges(); removeInvalidSlotRanges();
// Maps old slots to new slots. // Maps old slots to new slots.