From 7545f49a5edfe19612d03e683d8b955c03018056 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Sat, 13 Feb 2010 01:56:41 +0000 Subject: [PATCH] Teach MachineFrameInfo to track maximum alignment while stack objects are being created. This ensures it's updated at all time. It means targets which perform dynamic stack alignment would know whether it is required and whether frame pointer register cannot be made available register allocation. This is a fix for rdar://7625239. Sorry, I can't create a reasonably sized test case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96069 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/CodeGen/MachineFrameInfo.h | 16 +++------------- lib/CodeGen/PrologEpilogInserter.cpp | 15 ++------------- lib/Target/ARM/ARMBaseRegisterInfo.cpp | 8 -------- lib/Target/X86/X86RegisterInfo.cpp | 6 +----- 4 files changed, 6 insertions(+), 39 deletions(-) diff --git a/include/llvm/CodeGen/MachineFrameInfo.h b/include/llvm/CodeGen/MachineFrameInfo.h index 968e4eae3a6..043e97f9a7c 100644 --- a/include/llvm/CodeGen/MachineFrameInfo.h +++ b/include/llvm/CodeGen/MachineFrameInfo.h @@ -276,6 +276,7 @@ public: assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && "Invalid Object Idx!"); Objects[ObjectIdx+NumFixedObjects].Alignment = Align; + MaxAlignment = std::max(MaxAlignment, Align); } /// getObjectOffset - Return the assigned stack offset of the specified object @@ -328,19 +329,6 @@ public: /// void setMaxAlignment(unsigned Align) { MaxAlignment = Align; } - /// calculateMaxStackAlignment() - If there is a local object which requires - /// greater alignment than the current max alignment, adjust accordingly. - void calculateMaxStackAlignment() { - for (int i = getObjectIndexBegin(), - e = getObjectIndexEnd(); i != e; ++i) { - if (isDeadObjectIndex(i)) - continue; - - unsigned Align = getObjectAlignment(i); - MaxAlignment = std::max(MaxAlignment, Align); - } - } - /// hasCalls - Return true if the current function has no function calls. /// This is only valid during or after prolog/epilog code emission. /// @@ -402,6 +390,7 @@ public: Objects.push_back(StackObject(Size, Alignment, 0, false, isSS)); int Index = (int)Objects.size()-NumFixedObjects-1; assert(Index >= 0 && "Bad frame index!"); + MaxAlignment = std::max(MaxAlignment, Alignment); return Index; } @@ -412,6 +401,7 @@ public: int CreateSpillStackObject(uint64_t Size, unsigned Alignment) { CreateStackObject(Size, Alignment, true); int Index = (int)Objects.size()-NumFixedObjects-1; + MaxAlignment = std::max(MaxAlignment, Alignment); return Index; } diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp index 036f59a2a58..040259e15c5 100644 --- a/lib/CodeGen/PrologEpilogInserter.cpp +++ b/lib/CodeGen/PrologEpilogInserter.cpp @@ -476,8 +476,6 @@ void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) { // Loop over all of the stack objects, assigning sequential addresses... MachineFrameInfo *FFI = Fn.getFrameInfo(); - unsigned MaxAlign = 1; - // Start at the beginning of the local area. // The Offset is the distance from the stack top in the direction // of stack growth -- so it's always nonnegative. @@ -517,9 +515,6 @@ void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) { Offset += FFI->getObjectSize(i); unsigned Align = FFI->getObjectAlignment(i); - // 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; @@ -529,9 +524,6 @@ void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) { int MaxCSFI = MaxCSFrameIndex, MinCSFI = MinCSFrameIndex; for (int i = MaxCSFI; i >= MinCSFI ; --i) { unsigned Align = FFI->getObjectAlignment(i); - // 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; @@ -540,6 +532,8 @@ void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) { } } + unsigned MaxAlign = FFI->getMaxAlignment(); + // Make sure the special register scavenging spill slot is closest to the // frame pointer if a frame pointer is required. const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo(); @@ -605,11 +599,6 @@ void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) { // Update frame info to pretend that this is part of the stack... FFI->setStackSize(Offset - LocalAreaOffset); - - // Remember the required stack alignment in case targets need it to perform - // dynamic stack alignment. - if (MaxAlign > FFI->getMaxAlignment()) - FFI->setMaxAlignment(MaxAlign); } diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp index cb0bd1dbd24..91e3550d077 100644 --- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp +++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp @@ -583,14 +583,6 @@ ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, SmallVector UnspilledCS2GPRs; ARMFunctionInfo *AFI = MF.getInfo(); - - // Calculate and set max stack object alignment early, so we can decide - // whether we will need stack realignment (and thus FP). - if (RealignStack) { - MachineFrameInfo *MFI = MF.getFrameInfo(); - MFI->calculateMaxStackAlignment(); - } - // Spill R4 if Thumb2 function requires stack realignment - it will be used as // scratch register. // FIXME: It will be better just to find spare register here. diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp index 081c6d9061f..85242368c3c 100644 --- a/lib/Target/X86/X86RegisterInfo.cpp +++ b/lib/Target/X86/X86RegisterInfo.cpp @@ -485,7 +485,7 @@ X86RegisterInfo::getFrameIndexOffset(const MachineFunction &MF, int FI) const { Offset += SlotSize; } else { unsigned Align = MFI->getObjectAlignment(FI); - assert( (-(Offset + StackSize)) % Align == 0); + assert((-(Offset + StackSize)) % Align == 0); Align = 0; return Offset + StackSize; } @@ -627,10 +627,6 @@ X86RegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, RegScavenger *RS) const { MachineFrameInfo *MFI = MF.getFrameInfo(); - // Calculate and set max stack object alignment early, so we can decide - // whether we will need stack realignment (and thus FP). - MFI->calculateMaxStackAlignment(); - X86MachineFunctionInfo *X86FI = MF.getInfo(); int32_t TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta(); -- 2.34.1