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| author | Bob Wilson <bob.wilson@apple.com> | 2009-09-25 16:34:46 +0000 |
|---|---|---|
| committer | Bob Wilson <bob.wilson@apple.com> | 2009-09-25 16:34:46 +0000 |
| commit | c8ce2d4cb9ef5ff8b3c574e522c870741d88ba58 (patch) | |
| tree | 322db420ca6c31c5be67d6eda66abaeffebb1c52 | |
| parent | 42985bbe385264550cd01acfdb412abf0de316d3 (diff) | |
| download | llvm-c8ce2d4cb9ef5ff8b3c574e522c870741d88ba58.tar.gz llvm-c8ce2d4cb9ef5ff8b3c574e522c870741d88ba58.tar.bz2 llvm-c8ce2d4cb9ef5ff8b3c574e522c870741d88ba58.tar.xz | |
Add some comments to clarify things that I discovered this week.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82773 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Target/ARM/ARMBaseRegisterInfo.cpp | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp index 648f97fb1b..ab3dcd6992 100644 --- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp +++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp @@ -1151,6 +1151,7 @@ emitPrologue(MachineFunction &MF) const { unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0; int FramePtrSpillFI = 0; + // Allocate the vararg register save area. This is not counted in NumBytes. if (VARegSaveSize) emitSPUpdate(isARM, MBB, MBBI, dl, TII, -VARegSaveSize); @@ -1198,8 +1199,11 @@ emitPrologue(MachineFunction &MF) const { emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS1Size); movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 1, STI); - // Darwin ABI requires FP to point to the stack slot that contains the - // previous FP. + // Set FP to point to the stack slot that contains the previous FP. + // For Darwin, FP is R7, which has now been stored in spill area 1. + // Otherwise, if this is not Darwin, all the callee-saved registers go + // into spill area 1, including the FP in R11. In either case, it is + // now safe to emit this assignment. if (STI.isTargetDarwin() || hasFP(MF)) { unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri; MachineInstrBuilder MIB = |