aboutsummaryrefslogtreecommitdiff
path: root/lib/CodeGen/StackColoring.cpp
diff options
context:
space:
mode:
authorDimitry Andric <dim@FreeBSD.org>2017-08-08 16:52:53 +0000
committerDimitry Andric <dim@FreeBSD.org>2017-08-08 16:52:53 +0000
commit4e20bb0468b8d0db13287e666b482eb93689be99 (patch)
tree852306cf8c98c56c9c7db1a0860802199b2b3253 /lib/CodeGen/StackColoring.cpp
parent3ad6a4b447326bc16c17df65637ca02330b8d090 (diff)
Notes
Diffstat (limited to 'lib/CodeGen/StackColoring.cpp')
-rw-r--r--lib/CodeGen/StackColoring.cpp58
1 files changed, 51 insertions, 7 deletions
diff --git a/lib/CodeGen/StackColoring.cpp b/lib/CodeGen/StackColoring.cpp
index 6bac39c7ee77..e5fc5402cb41 100644
--- a/lib/CodeGen/StackColoring.cpp
+++ b/lib/CodeGen/StackColoring.cpp
@@ -37,6 +37,7 @@
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
+#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/SlotIndexes.h"
#include "llvm/CodeGen/StackProtector.h"
#include "llvm/CodeGen/WinEHFuncInfo.h"
@@ -889,6 +890,10 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
// Keep a list of *allocas* which need to be remapped.
DenseMap<const AllocaInst*, const AllocaInst*> Allocas;
+
+ // Keep a list of allocas which has been affected by the remap.
+ SmallPtrSet<const AllocaInst*, 32> MergedAllocas;
+
for (const std::pair<int, int> &SI : SlotRemap) {
const AllocaInst *From = MFI->getObjectAllocation(SI.first);
const AllocaInst *To = MFI->getObjectAllocation(SI.second);
@@ -908,6 +913,10 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
Inst = Cast;
}
+ // We keep both slots to maintain AliasAnalysis metadata later.
+ MergedAllocas.insert(From);
+ MergedAllocas.insert(To);
+
// Allow the stack protector to adjust its value map to account for the
// upcoming replacement.
SP->adjustForColoring(From, To);
@@ -939,13 +948,6 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
// Update the MachineMemOperand to use the new alloca.
for (MachineMemOperand *MMO : I.memoperands()) {
- // FIXME: In order to enable the use of TBAA when using AA in CodeGen,
- // we'll also need to update the TBAA nodes in MMOs with values
- // derived from the merged allocas. When doing this, we'll need to use
- // the same variant of GetUnderlyingObjects that is used by the
- // instruction scheduler (that can look through ptrtoint/inttoptr
- // pairs).
-
// We've replaced IR-level uses of the remapped allocas, so we only
// need to replace direct uses here.
const AllocaInst *AI = dyn_cast_or_null<AllocaInst>(MMO->getValue());
@@ -997,6 +999,48 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
MO.setIndex(ToSlot);
FixedInstr++;
}
+
+ // We adjust AliasAnalysis information for merged stack slots.
+ MachineSDNode::mmo_iterator NewMemOps =
+ MF->allocateMemRefsArray(I.getNumMemOperands());
+ unsigned MemOpIdx = 0;
+ bool ReplaceMemOps = false;
+ for (MachineMemOperand *MMO : I.memoperands()) {
+ // If this memory location can be a slot remapped here,
+ // we remove AA information.
+ bool MayHaveConflictingAAMD = false;
+ if (MMO->getAAInfo()) {
+ if (const Value *MMOV = MMO->getValue()) {
+ SmallVector<Value *, 4> Objs;
+ getUnderlyingObjectsForCodeGen(MMOV, Objs, MF->getDataLayout());
+
+ if (Objs.empty())
+ MayHaveConflictingAAMD = true;
+ else
+ for (Value *V : Objs) {
+ // If this memory location comes from a known stack slot
+ // that is not remapped, we continue checking.
+ // Otherwise, we need to invalidate AA infomation.
+ const AllocaInst *AI = dyn_cast_or_null<AllocaInst>(V);
+ if (AI && MergedAllocas.count(AI)) {
+ MayHaveConflictingAAMD = true;
+ break;
+ }
+ }
+ }
+ }
+ if (MayHaveConflictingAAMD) {
+ NewMemOps[MemOpIdx++] = MF->getMachineMemOperand(MMO, AAMDNodes());
+ ReplaceMemOps = true;
+ }
+ else
+ NewMemOps[MemOpIdx++] = MMO;
+ }
+
+ // If any memory operand is updated, set memory references of
+ // this instruction.
+ if (ReplaceMemOps)
+ I.setMemRefs(std::make_pair(NewMemOps, I.getNumMemOperands()));
}
// Update the location of C++ catch objects for the MSVC personality routine.