Add the necessary support to the ISel to allow targets to codegen the new
alignment information appropriately. Includes code for PowerPC to support
fixed-size allocas with alignment larger than the stack. Support for
arbitrarily aligned dynamic allocas coming soon.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24224 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp
index e38c740..9593220 100644
--- a/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/lib/CodeGen/PrologEpilogInserter.cpp
@@ -258,6 +258,7 @@
MachineFrameInfo *FFI = Fn.getFrameInfo();
unsigned StackAlignment = TFI.getStackAlignment();
+ unsigned MaxAlign = StackAlignment;
// Start at the beginning of the local area.
// The Offset is the distance from the stack top in the direction
@@ -295,9 +296,11 @@
Offset += FFI->getObjectSize(i);
unsigned Align = FFI->getObjectAlignment(i);
- assert(Align <= StackAlignment && "Cannot align stack object to higher "
- "alignment boundary than the stack itself!");
- Offset = (Offset+Align-1)/Align*Align; // Adjust to Alignment boundary...
+ // If the alignment of this object is greater than that of the stack, then
+ // increase the stack alignment to match.
+ MaxAlign = std::max(MaxAlign, Align);
+ // Adjust to alignment boundary
+ Offset = (Offset+Align-1)/Align*Align;
if (StackGrowsDown) {
FFI->setObjectOffset(i, -Offset); // Set the computed offset
@@ -315,6 +318,11 @@
// Set the final value of the stack pointer...
FFI->setStackSize(Offset+TFI.getOffsetOfLocalArea());
+ // If we have a new stack alignment, set the preferred stack alignment so that
+ // the targets can do the appropriate thing to properly align the stack above
+ // the default alignment.
+ if (MaxAlign > StackAlignment)
+ FFI->setMaxAlignment(MaxAlign);
}
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 3b5ef32..64256c9 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -147,7 +147,9 @@
if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(AI->getArraySize())) {
const Type *Ty = AI->getAllocatedType();
uint64_t TySize = TLI.getTargetData().getTypeSize(Ty);
- unsigned Align = TLI.getTargetData().getTypeAlignment(Ty);
+ unsigned Align =
+ std::max((unsigned)TLI.getTargetData().getTypeAlignment(Ty),
+ AI->getAlignment());
// If the alignment of the value is smaller than the size of the value,
// and if the size of the value is particularly small (<= 8 bytes),
@@ -636,7 +638,8 @@
const Type *Ty = I.getAllocatedType();
uint64_t TySize = TLI.getTargetData().getTypeSize(Ty);
- unsigned Align = TLI.getTargetData().getTypeAlignment(Ty);
+ unsigned Align = std::max((unsigned)TLI.getTargetData().getTypeAlignment(Ty),
+ I.getAlignment());
SDOperand AllocSize = getValue(I.getArraySize());
MVT::ValueType IntPtr = TLI.getPointerTy();