ARM: Compute MaxCallFrame size early
This exposes a method in MachineFrameInfo that calculates
MaxCallFrameSize and calls it after instruction selection in the ARM
target.
This avoids
ARMBaseRegisterInfo::canRealignStack()/ARMFrameLowering::hasReservedCallFrame()
giving different answers in early/late phases of codegen.
The testcase shows a particular nasty example result of that where we
would fail to properly align an alloca.
Differential Revision: https://reviews.llvm.org/D32622
llvm-svn: 302303
diff --git a/llvm/lib/CodeGen/MachineFrameInfo.cpp b/llvm/lib/CodeGen/MachineFrameInfo.cpp
index 7de8434..73d778f 100644
--- a/llvm/lib/CodeGen/MachineFrameInfo.cpp
+++ b/llvm/lib/CodeGen/MachineFrameInfo.cpp
@@ -19,6 +19,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetFrameLowering.h"
+#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include <cassert>
@@ -175,6 +176,31 @@
return (unsigned)Offset;
}
+void MachineFrameInfo::computeMaxCallFrameSize(const MachineFunction &MF) {
+ const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
+ unsigned FrameSetupOpcode = TII.getCallFrameSetupOpcode();
+ unsigned FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
+ assert(FrameSetupOpcode != ~0u && FrameDestroyOpcode != ~0u &&
+ "Can only compute MaxCallFrameSize if Setup/Destroy opcode are known");
+
+ MaxCallFrameSize = 0;
+ for (const MachineBasicBlock &MBB : MF) {
+ for (const MachineInstr &MI : MBB) {
+ unsigned Opcode = MI.getOpcode();
+ if (Opcode == FrameSetupOpcode || Opcode == FrameDestroyOpcode) {
+ unsigned Size = TII.getFrameSize(MI);
+ MaxCallFrameSize = std::max(MaxCallFrameSize, Size);
+ AdjustsStack = true;
+ } else if (MI.isInlineAsm()) {
+ // Some inline asm's need a stack frame, as indicated by operand 1.
+ unsigned ExtraInfo = MI.getOperand(InlineAsm::MIOp_ExtraInfo).getImm();
+ if (ExtraInfo & InlineAsm::Extra_IsAlignStack)
+ AdjustsStack = true;
+ }
+ }
+ }
+}
+
void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
if (Objects.empty()) return;