[llvm-commits] [llvm] r111836 - in /llvm/trunk/lib/CodeGen: LocalStackSlotAllocation.cpp PrologEpilogInserter.cpp
Jim Grosbach
grosbach at apple.com
Mon Aug 23 13:40:38 PDT 2010
Author: grosbach
Date: Mon Aug 23 15:40:38 2010
New Revision: 111836
URL: http://llvm.org/viewvc/llvm-project?rev=111836&view=rev
Log:
Better handling of local offsets for downwards growing stacks. This corrects
relative offsets when there are offsets encoded in the instructions and
simplifies final allocation in PEI. rdar://8277890
Modified:
llvm/trunk/lib/CodeGen/LocalStackSlotAllocation.cpp
llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
Modified: llvm/trunk/lib/CodeGen/LocalStackSlotAllocation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LocalStackSlotAllocation.cpp?rev=111836&r1=111835&r2=111836&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LocalStackSlotAllocation.cpp (original)
+++ llvm/trunk/lib/CodeGen/LocalStackSlotAllocation.cpp Mon Aug 23 15:40:38 2010
@@ -46,7 +46,7 @@
SmallVector<int64_t,16> LocalOffsets;
void AdjustStackOffset(MachineFrameInfo *MFI, int FrameIdx, int64_t &Offset,
- unsigned &MaxAlign);
+ bool StackGrowsDown, unsigned &MaxAlign);
void calculateFrameObjectOffsets(MachineFunction &Fn);
bool insertFrameReferenceRegisters(MachineFunction &Fn);
public:
@@ -102,7 +102,12 @@
/// AdjustStackOffset - Helper function used to adjust the stack frame offset.
void LocalStackSlotPass::AdjustStackOffset(MachineFrameInfo *MFI,
int FrameIdx, int64_t &Offset,
+ bool StackGrowsDown,
unsigned &MaxAlign) {
+ // If the stack grows down, add the object size to find the lowest address.
+ if (StackGrowsDown)
+ Offset += MFI->getObjectSize(FrameIdx);
+
unsigned Align = MFI->getObjectAlignment(FrameIdx);
// If the alignment of this object is greater than that of the stack, then
@@ -112,13 +117,16 @@
// Adjust to alignment boundary.
Offset = (Offset + Align - 1) / Align * Align;
+ int64_t LocalOffset = StackGrowsDown ? -Offset : Offset;
DEBUG(dbgs() << "Allocate FI(" << FrameIdx << ") to local offset "
- << Offset << "\n");
+ << LocalOffset << "\n");
// Keep the offset available for base register allocation
- LocalOffsets[FrameIdx] = Offset;
+ LocalOffsets[FrameIdx] = LocalOffset;
// And tell MFI about it for PEI to use later
- MFI->mapLocalFrameObject(FrameIdx, Offset);
- Offset += MFI->getObjectSize(FrameIdx);
+ MFI->mapLocalFrameObject(FrameIdx, LocalOffset);
+
+ if (!StackGrowsDown)
+ Offset += MFI->getObjectSize(FrameIdx);
++NumAllocations;
}
@@ -129,6 +137,9 @@
void LocalStackSlotPass::calculateFrameObjectOffsets(MachineFunction &Fn) {
// Loop over all of the stack objects, assigning sequential addresses...
MachineFrameInfo *MFI = Fn.getFrameInfo();
+ const TargetFrameInfo &TFI = *Fn.getTarget().getFrameInfo();
+ bool StackGrowsDown =
+ TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
int64_t Offset = 0;
unsigned MaxAlign = 0;
@@ -136,7 +147,8 @@
// stack.
SmallSet<int, 16> LargeStackObjs;
if (MFI->getStackProtectorIndex() >= 0) {
- AdjustStackOffset(MFI, MFI->getStackProtectorIndex(), Offset, MaxAlign);
+ AdjustStackOffset(MFI, MFI->getStackProtectorIndex(), Offset,
+ StackGrowsDown, MaxAlign);
// Assign large stack objects first.
for (unsigned i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
@@ -147,7 +159,7 @@
if (!MFI->MayNeedStackProtector(i))
continue;
- AdjustStackOffset(MFI, i, Offset, MaxAlign);
+ AdjustStackOffset(MFI, i, Offset, StackGrowsDown, MaxAlign);
LargeStackObjs.insert(i);
}
}
@@ -162,7 +174,7 @@
if (LargeStackObjs.count(i))
continue;
- AdjustStackOffset(MFI, i, Offset, MaxAlign);
+ AdjustStackOffset(MFI, i, Offset, StackGrowsDown, MaxAlign);
}
// Remember how big this blob of stack space is
@@ -173,8 +185,8 @@
static inline bool
lookupCandidateBaseReg(const SmallVector<std::pair<unsigned, int64_t>, 8> &Regs,
std::pair<unsigned, int64_t> &RegOffset,
+ int64_t FrameSizeAdjust,
int64_t LocalFrameOffset,
- bool StackGrowsDown,
const MachineInstr *MI,
const TargetRegisterInfo *TRI) {
unsigned e = Regs.size();
@@ -182,9 +194,7 @@
RegOffset = Regs[i];
// Check if the relative offset from the where the base register references
// to the target address is in range for the instruction.
- int64_t Offset = LocalFrameOffset - RegOffset.second;
- if (StackGrowsDown)
- Offset = -Offset;
+ int64_t Offset = FrameSizeAdjust + LocalFrameOffset - RegOffset.second;
if (TRI->isFrameOffsetLegal(MI, Offset))
return true;
}
@@ -241,6 +251,8 @@
if (TRI->needsFrameBaseReg(MI, i)) {
unsigned BaseReg = 0;
int64_t Offset = 0;
+ int64_t FrameSizeAdjust = StackGrowsDown ? MFI->getLocalFrameSize()
+ : 0;
DEBUG(dbgs() << " Replacing FI in: " << *MI);
@@ -251,15 +263,15 @@
// register.
std::pair<unsigned, int64_t> RegOffset;
if (lookupCandidateBaseReg(BaseRegisters, RegOffset,
+ FrameSizeAdjust,
LocalOffsets[FrameIdx],
- StackGrowsDown, MI, TRI)) {
+ MI, TRI)) {
DEBUG(dbgs() << " Reusing base register " <<
RegOffset.first << "\n");
// We found a register to reuse.
BaseReg = RegOffset.first;
- Offset = LocalOffsets[FrameIdx] - RegOffset.second;
- if (StackGrowsDown)
- Offset = -Offset;
+ Offset = FrameSizeAdjust + LocalOffsets[FrameIdx] -
+ RegOffset.second;
} else {
// No previously defined register was in range, so create a
// new one.
@@ -280,9 +292,10 @@
// applied twice.
Offset = -InstrOffset;
+ int64_t BaseOffset = FrameSizeAdjust + LocalOffsets[FrameIdx] +
+ InstrOffset;
BaseRegisters.push_back(
- std::pair<unsigned, int64_t>(BaseReg,
- LocalOffsets[FrameIdx] + InstrOffset));
+ std::pair<unsigned, int64_t>(BaseReg, BaseOffset));
++NumBaseRegisters;
UsedBaseReg = true;
}
@@ -295,7 +308,6 @@
++NumReplacements;
}
-
}
}
}
Modified: llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp?rev=111836&r1=111835&r2=111836&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp (original)
+++ llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp Mon Aug 23 15:40:38 2010
@@ -572,16 +572,18 @@
DEBUG(dbgs() << "Local frame base offset: " << Offset << "\n");
- // Allocate the local block
- Offset += MFI->getLocalFrameSize();
-
// Resolve offsets for objects in the local block.
for (unsigned i = 0, e = MFI->getLocalFrameObjectCount(); i != e; ++i) {
std::pair<int, int64_t> Entry = MFI->getLocalFrameObjectMap(i);
- int64_t FIOffset = MFI->getLocalFrameBaseOffset() + Entry.second;
-
- AdjustStackOffset(MFI, Entry.first, StackGrowsDown, FIOffset, MaxAlign);
+ int64_t FIOffset = (StackGrowsDown ? -Offset : Offset) + Entry.second;
+ DEBUG(dbgs() << "alloc FI(" << Entry.first << ") at SP[" <<
+ FIOffset << "]\n");
+ MFI->setObjectOffset(Entry.first, FIOffset);
}
+ // Allocate the local block
+ Offset += MFI->getLocalFrameSize();
+
+ MaxAlign = std::max(Align, MaxAlign);
}
// Make sure that the stack protector comes before the local variables on the
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