[llvm-commits] [llvm] r111315 - in /llvm/trunk: include/llvm/Target/TargetRegisterInfo.h lib/CodeGen/LocalStackSlotAllocation.cpp lib/CodeGen/PrologEpilogInserter.cpp lib/Target/ARM/ARMBaseRegisterInfo.cpp lib/Target/ARM/ARMBaseRegisterInfo.h
Jim Grosbach
grosbach at apple.com
Tue Aug 17 15:41:55 PDT 2010
Author: grosbach
Date: Tue Aug 17 17:41:55 2010
New Revision: 111315
URL: http://llvm.org/viewvc/llvm-project?rev=111315&view=rev
Log:
Add materialization of virtual base registers for frame indices allocated into
the local block. Resolve references to those indices to a new base register.
For simplification and testing purposes, a new virtual base register is
allocated for each frame index being resolved. The result is truly horrible,
but correct, code that's good for exercising the new code paths.
Next up is adding thumb1 support, which should be very simple. Following that
will be adding base register re-use and implementing a reasonable ARM
heuristic for when a virtual base register should be generated at all.
Modified:
llvm/trunk/include/llvm/Target/TargetRegisterInfo.h
llvm/trunk/lib/CodeGen/LocalStackSlotAllocation.cpp
llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp
llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h
Modified: llvm/trunk/include/llvm/Target/TargetRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetRegisterInfo.h?rev=111315&r1=111314&r2=111315&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetRegisterInfo.h (original)
+++ llvm/trunk/include/llvm/Target/TargetRegisterInfo.h Tue Aug 17 17:41:55 2010
@@ -644,6 +644,22 @@
return false;
}
+ /// materializeFrameBaseRegister - Insert defining instruction(s) for
+ /// BaseReg to be a pointer to FrameIdx before insertion point I.
+ virtual void materializeFrameBaseRegister(MachineBasicBlock::iterator I,
+ unsigned BaseReg,
+ int FrameIdx) const {
+ assert(0 && "materializeFrameBaseRegister does not exist on this target");
+ }
+
+ /// resolveFrameIndex - Resolve a frame index operand of an instruction
+ /// to reference the indicated base register plus offset instead.
+ virtual void resolveFrameIndex(MachineBasicBlock::iterator I,
+ unsigned BaseReg, int64_t Offset) const {
+ assert(0 && "resolveFrameIndex does not exist on this target");
+ }
+
+
/// getCallFrameSetup/DestroyOpcode - These methods return the opcode of the
/// frame setup/destroy instructions if they exist (-1 otherwise). Some
/// targets use pseudo instructions in order to abstract away the difference
Modified: llvm/trunk/lib/CodeGen/LocalStackSlotAllocation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LocalStackSlotAllocation.cpp?rev=111315&r1=111314&r2=111315&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LocalStackSlotAllocation.cpp (original)
+++ llvm/trunk/lib/CodeGen/LocalStackSlotAllocation.cpp Tue Aug 17 17:41:55 2010
@@ -27,6 +27,7 @@
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
@@ -160,6 +161,14 @@
E = Fn.end(); BB != E; ++BB) {
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
MachineInstr *MI = I;
+ // Debug value instructions can't be out of range, so they don't need
+ // any updates.
+ // FIXME: When we extend this stuff to handle functions with both
+ // VLAs and dynamic realignment, we should update the debug values
+ // to reference the new base pointer when possible.
+ if (MI->isDebugValue())
+ continue;
+
// For now, allocate the base register(s) within the basic block
// where they're used, and don't try to keep them around outside
// of that. It may be beneficial to try sharing them more broadly
@@ -169,8 +178,12 @@
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
// Consider replacing all frame index operands that reference
// an object allocated in the local block.
- if (MI->getOperand(i).isFI() &&
- MFI->isObjectPreAllocated(MI->getOperand(i).getIndex())) {
+ if (MI->getOperand(i).isFI()) {
+ int FrameIdx = MI->getOperand(i).getIndex();
+ // Don't try this with values not in the local block.
+ if (!MFI->isObjectPreAllocated(FrameIdx))
+ continue;
+
DEBUG(dbgs() << "Considering: " << *MI);
if (TRI->needsFrameBaseReg(MI, i)) {
DEBUG(dbgs() << " Replacing FI in: " << *MI);
@@ -182,6 +195,17 @@
// create a new one.
// FIXME: For the moment, just always create a new one.
+ const TargetRegisterClass *RC = TRI->getPointerRegClass();
+ unsigned BaseReg = Fn.getRegInfo().createVirtualRegister(RC);
+
+ // Tell the target to insert the instruction to initialize
+ // the base register.
+ TRI->materializeFrameBaseRegister(I, BaseReg, FrameIdx);
+
+ // Modify the instruction to use the new base register rather
+ // than the frame index operand.
+ TRI->resolveFrameIndex(I, BaseReg, 0);
+
++NumBaseRegisters;
++NumReplacements;
}
Modified: llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp?rev=111315&r1=111314&r2=111315&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp (original)
+++ llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp Tue Aug 17 17:41:55 2010
@@ -560,7 +560,7 @@
// check for whether the frame is large enough to want to use virtual
// frame index registers. Functions which don't want/need this optimization
// will continue to use the existing code path.
- if (EnableLocalStackAlloc) {
+ if (EnableLocalStackAlloc && MFI->getLocalFrameSize()) {
unsigned Align = MFI->getLocalFrameMaxAlign();
// Adjust to alignment boundary.
Modified: llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp?rev=111315&r1=111314&r2=111315&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp Tue Aug 17 17:41:55 2010
@@ -1407,6 +1407,49 @@
}
}
+/// materializeFrameBaseRegister - Insert defining instruction(s) for
+/// BaseReg to be a pointer to FrameIdx before insertion point I.
+void ARMBaseRegisterInfo::
+materializeFrameBaseRegister(MachineBasicBlock::iterator I,
+ unsigned BaseReg, int FrameIdx) const {
+ ARMFunctionInfo *AFI =
+ I->getParent()->getParent()->getInfo<ARMFunctionInfo>();
+ unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri;
+ assert(!AFI->isThumb1OnlyFunction() &&
+ "This materializeFrameBaseRegister does not support Thumb1!");
+
+ MachineInstrBuilder MIB =
+ BuildMI(*I->getParent(), I, I->getDebugLoc(), TII.get(ADDriOpc), BaseReg)
+ .addFrameIndex(FrameIdx).addImm(0);
+ AddDefaultCC(AddDefaultPred(MIB));
+}
+
+void
+ARMBaseRegisterInfo::resolveFrameIndex(MachineBasicBlock::iterator I,
+ unsigned BaseReg, int64_t Offset) const {
+ MachineInstr &MI = *I;
+ MachineBasicBlock &MBB = *MI.getParent();
+ MachineFunction &MF = *MBB.getParent();
+ ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+ int Off = Offset; // ARM doesn't need the general 64-bit offsets
+ unsigned i = 0;
+
+ assert(!AFI->isThumb1OnlyFunction() &&
+ "This resolveFrameIndex does not support Thumb1!");
+
+ while (!MI.getOperand(i).isFI()) {
+ ++i;
+ assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
+ }
+ bool Done = false;
+ if (!AFI->isThumbFunction())
+ Done = rewriteARMFrameIndex(MI, i, BaseReg, Off, TII);
+ else {
+ assert(AFI->isThumb2Function());
+ Done = rewriteT2FrameIndex(MI, i, BaseReg, Off, TII);
+ }
+ assert (Done && "Unable to resolve frame index!");
+}
unsigned
ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
Modified: llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h?rev=111315&r1=111314&r2=111315&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h (original)
+++ llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h Tue Aug 17 17:41:55 2010
@@ -106,6 +106,10 @@
bool canRealignStack(const MachineFunction &MF) const;
bool needsStackRealignment(const MachineFunction &MF) const;
bool needsFrameBaseReg(MachineInstr *MI, unsigned operand) const;
+ void materializeFrameBaseRegister(MachineBasicBlock::iterator I,
+ unsigned BaseReg, int FrameIdx) const;
+ void resolveFrameIndex(MachineBasicBlock::iterator I,
+ unsigned BaseReg, int64_t Offset) const;
bool cannotEliminateFrame(const MachineFunction &MF) const;
More information about the llvm-commits
mailing list