[mips] Add function MipsFrameLowering::estimateStackSize.
This function estimates stack size and will be called before
PrologEpilogInserter scans the callee-saved registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167313 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsFrameLowering.cpp b/lib/Target/Mips/MipsFrameLowering.cpp
index 6dd251c..2cad2a6 100644
--- a/lib/Target/Mips/MipsFrameLowering.cpp
+++ b/lib/Target/Mips/MipsFrameLowering.cpp
@@ -98,3 +98,37 @@
return MF.getTarget().Options.DisableFramePointerElim(MF) ||
MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken();
}
+
+uint64_t MipsFrameLowering::estimateStackSize(const MachineFunction &MF) const {
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+ const TargetRegisterInfo &TRI = *MF.getTarget().getRegisterInfo();
+
+ int64_t Offset = 0;
+
+ // Iterate over fixed sized objects.
+ for (int I = MFI->getObjectIndexBegin(); I != 0; ++I)
+ Offset = std::max(Offset, -MFI->getObjectOffset(I));
+
+ // Conservatively assume all callee-saved registers will be saved.
+ for (const uint16_t *R = TRI.getCalleeSavedRegs(&MF); *R; ++R) {
+ unsigned Size = TRI.getMinimalPhysRegClass(*R)->getSize();
+ Offset = RoundUpToAlignment(Offset + Size, Size);
+ }
+
+ unsigned MaxAlign = MFI->getMaxAlignment();
+
+ // Check that MaxAlign is not zero if there is a stack object that is not a
+ // callee-saved spill.
+ assert(!MFI->getObjectIndexEnd() || MaxAlign);
+
+ // Iterate over other objects.
+ for (unsigned I = 0, E = MFI->getObjectIndexEnd(); I != E; ++I)
+ Offset = RoundUpToAlignment(Offset + MFI->getObjectSize(I), MaxAlign);
+
+ // Call frame.
+ if (MFI->adjustsStack() && hasReservedCallFrame(MF))
+ Offset = RoundUpToAlignment(Offset + MFI->getMaxCallFrameSize(),
+ std::max(MaxAlign, getStackAlignment()));
+
+ return RoundUpToAlignment(Offset, getStackAlignment());
+}