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-rw-r--r--lib/Target/ARM/ARMConstantIslandPass.cpp775
1 files changed, 515 insertions, 260 deletions
diff --git a/lib/Target/ARM/ARMConstantIslandPass.cpp b/lib/Target/ARM/ARMConstantIslandPass.cpp
index 9fedaa465434..309e3ba2ac25 100644
--- a/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -15,24 +15,31 @@
#define DEBUG_TYPE "arm-cp-islands"
#include "ARM.h"
+#include "ARMAddressingModes.h"
#include "ARMMachineFunctionInfo.h"
#include "ARMInstrInfo.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
-STATISTIC(NumCPEs, "Number of constpool entries");
-STATISTIC(NumSplit, "Number of uncond branches inserted");
-STATISTIC(NumCBrFixed, "Number of cond branches fixed");
-STATISTIC(NumUBrFixed, "Number of uncond branches fixed");
+STATISTIC(NumCPEs, "Number of constpool entries");
+STATISTIC(NumSplit, "Number of uncond branches inserted");
+STATISTIC(NumCBrFixed, "Number of cond branches fixed");
+STATISTIC(NumUBrFixed, "Number of uncond branches fixed");
+STATISTIC(NumTBs, "Number of table branches generated");
+STATISTIC(NumT2CPShrunk, "Number of Thumb2 constantpool instructions shrunk");
+STATISTIC(NumT2BrShrunk, "Number of Thumb2 immediate branches shrunk");
namespace {
/// ARMConstantIslands - Due to limited PC-relative displacements, ARM
@@ -63,6 +70,8 @@ namespace {
/// to a return, unreachable, or unconditional branch).
std::vector<MachineBasicBlock*> WaterList;
+ typedef std::vector<MachineBasicBlock*>::iterator water_iterator;
+
/// CPUser - One user of a constant pool, keeping the machine instruction
/// pointer, the constant pool being referenced, and the max displacement
/// allowed from the instruction to the CP.
@@ -70,8 +79,11 @@ namespace {
MachineInstr *MI;
MachineInstr *CPEMI;
unsigned MaxDisp;
- CPUser(MachineInstr *mi, MachineInstr *cpemi, unsigned maxdisp)
- : MI(mi), CPEMI(cpemi), MaxDisp(maxdisp) {}
+ bool NegOk;
+ bool IsSoImm;
+ CPUser(MachineInstr *mi, MachineInstr *cpemi, unsigned maxdisp,
+ bool neg, bool soimm)
+ : MI(mi), CPEMI(cpemi), MaxDisp(maxdisp), NegOk(neg), IsSoImm(soimm) {}
};
/// CPUsers - Keep track of all of the machine instructions that use various
@@ -117,29 +129,34 @@ namespace {
///
SmallVector<MachineInstr*, 4> PushPopMIs;
+ /// T2JumpTables - Keep track of all the Thumb2 jumptable instructions.
+ SmallVector<MachineInstr*, 4> T2JumpTables;
+
/// HasFarJump - True if any far jump instruction has been emitted during
/// the branch fix up pass.
bool HasFarJump;
const TargetInstrInfo *TII;
+ const ARMSubtarget *STI;
ARMFunctionInfo *AFI;
bool isThumb;
+ bool isThumb1;
bool isThumb2;
public:
static char ID;
ARMConstantIslands() : MachineFunctionPass(&ID) {}
- virtual bool runOnMachineFunction(MachineFunction &Fn);
+ virtual bool runOnMachineFunction(MachineFunction &MF);
virtual const char *getPassName() const {
return "ARM constant island placement and branch shortening pass";
}
private:
- void DoInitialPlacement(MachineFunction &Fn,
+ void DoInitialPlacement(MachineFunction &MF,
std::vector<MachineInstr*> &CPEMIs);
CPEntry *findConstPoolEntry(unsigned CPI, const MachineInstr *CPEMI);
- void InitialFunctionScan(MachineFunction &Fn,
+ void InitialFunctionScan(MachineFunction &MF,
const std::vector<MachineInstr*> &CPEMIs);
MachineBasicBlock *SplitBlockBeforeInstr(MachineInstr *MI);
void UpdateForInsertedWaterBlock(MachineBasicBlock *NewBB);
@@ -147,58 +164,62 @@ namespace {
bool DecrementOldEntry(unsigned CPI, MachineInstr* CPEMI);
int LookForExistingCPEntry(CPUser& U, unsigned UserOffset);
bool LookForWater(CPUser&U, unsigned UserOffset,
- MachineBasicBlock** NewMBB);
- MachineBasicBlock* AcceptWater(MachineBasicBlock *WaterBB,
- std::vector<MachineBasicBlock*>::iterator IP);
+ MachineBasicBlock *&NewMBB);
+ MachineBasicBlock *AcceptWater(water_iterator IP);
void CreateNewWater(unsigned CPUserIndex, unsigned UserOffset,
- MachineBasicBlock** NewMBB);
- bool HandleConstantPoolUser(MachineFunction &Fn, unsigned CPUserIndex);
+ MachineBasicBlock *&NewMBB);
+ bool HandleConstantPoolUser(MachineFunction &MF, unsigned CPUserIndex);
void RemoveDeadCPEMI(MachineInstr *CPEMI);
bool RemoveUnusedCPEntries();
bool CPEIsInRange(MachineInstr *MI, unsigned UserOffset,
- MachineInstr *CPEMI, unsigned Disp,
- bool DoDump);
+ MachineInstr *CPEMI, unsigned Disp, bool NegOk,
+ bool DoDump = false);
bool WaterIsInRange(unsigned UserOffset, MachineBasicBlock *Water,
CPUser &U);
bool OffsetIsInRange(unsigned UserOffset, unsigned TrialOffset,
- unsigned Disp, bool NegativeOK);
+ unsigned Disp, bool NegativeOK, bool IsSoImm = false);
bool BBIsInRange(MachineInstr *MI, MachineBasicBlock *BB, unsigned Disp);
- bool FixUpImmediateBr(MachineFunction &Fn, ImmBranch &Br);
- bool FixUpConditionalBr(MachineFunction &Fn, ImmBranch &Br);
- bool FixUpUnconditionalBr(MachineFunction &Fn, ImmBranch &Br);
+ bool FixUpImmediateBr(MachineFunction &MF, ImmBranch &Br);
+ bool FixUpConditionalBr(MachineFunction &MF, ImmBranch &Br);
+ bool FixUpUnconditionalBr(MachineFunction &MF, ImmBranch &Br);
bool UndoLRSpillRestore();
+ bool OptimizeThumb2Instructions(MachineFunction &MF);
+ bool OptimizeThumb2Branches(MachineFunction &MF);
+ bool OptimizeThumb2JumpTables(MachineFunction &MF);
unsigned GetOffsetOf(MachineInstr *MI) const;
void dumpBBs();
- void verify(MachineFunction &Fn);
+ void verify(MachineFunction &MF);
};
char ARMConstantIslands::ID = 0;
}
/// verify - check BBOffsets, BBSizes, alignment of islands
-void ARMConstantIslands::verify(MachineFunction &Fn) {
+void ARMConstantIslands::verify(MachineFunction &MF) {
assert(BBOffsets.size() == BBSizes.size());
for (unsigned i = 1, e = BBOffsets.size(); i != e; ++i)
assert(BBOffsets[i-1]+BBSizes[i-1] == BBOffsets[i]);
- if (isThumb) {
- for (MachineFunction::iterator MBBI = Fn.begin(), E = Fn.end();
- MBBI != E; ++MBBI) {
- MachineBasicBlock *MBB = MBBI;
- if (!MBB->empty() &&
- MBB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY)
- assert((BBOffsets[MBB->getNumber()]%4 == 0 &&
- BBSizes[MBB->getNumber()]%4 == 0) ||
- (BBOffsets[MBB->getNumber()]%4 != 0 &&
- BBSizes[MBB->getNumber()]%4 != 0));
+ if (!isThumb)
+ return;
+#ifndef NDEBUG
+ for (MachineFunction::iterator MBBI = MF.begin(), E = MF.end();
+ MBBI != E; ++MBBI) {
+ MachineBasicBlock *MBB = MBBI;
+ if (!MBB->empty() &&
+ MBB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY) {
+ unsigned MBBId = MBB->getNumber();
+ assert((BBOffsets[MBBId]%4 == 0 && BBSizes[MBBId]%4 == 0) ||
+ (BBOffsets[MBBId]%4 != 0 && BBSizes[MBBId]%4 != 0));
}
}
+#endif
}
/// print block size and offset information - debugging
void ARMConstantIslands::dumpBBs() {
for (unsigned J = 0, E = BBOffsets.size(); J !=E; ++J) {
- DOUT << "block " << J << " offset " << BBOffsets[J] <<
- " size " << BBSizes[J] << "\n";
+ DEBUG(errs() << "block " << J << " offset " << BBOffsets[J]
+ << " size " << BBSizes[J] << "\n");
}
}
@@ -208,31 +229,36 @@ FunctionPass *llvm::createARMConstantIslandPass() {
return new ARMConstantIslands();
}
-bool ARMConstantIslands::runOnMachineFunction(MachineFunction &Fn) {
- MachineConstantPool &MCP = *Fn.getConstantPool();
+bool ARMConstantIslands::runOnMachineFunction(MachineFunction &MF) {
+ MachineConstantPool &MCP = *MF.getConstantPool();
+
+ TII = MF.getTarget().getInstrInfo();
+ AFI = MF.getInfo<ARMFunctionInfo>();
+ STI = &MF.getTarget().getSubtarget<ARMSubtarget>();
- TII = Fn.getTarget().getInstrInfo();
- AFI = Fn.getInfo<ARMFunctionInfo>();
isThumb = AFI->isThumbFunction();
+ isThumb1 = AFI->isThumb1OnlyFunction();
isThumb2 = AFI->isThumb2Function();
HasFarJump = false;
// Renumber all of the machine basic blocks in the function, guaranteeing that
// the numbers agree with the position of the block in the function.
- Fn.RenumberBlocks();
+ MF.RenumberBlocks();
+
+ // Thumb1 functions containing constant pools get 4-byte alignment.
+ // This is so we can keep exact track of where the alignment padding goes.
- /// Thumb functions containing constant pools get 2-byte alignment.
- /// This is so we can keep exact track of where the alignment padding goes.
- /// Set default.
- AFI->setAlign(isThumb ? 1U : 2U);
+ // Set default. Thumb1 function is 2-byte aligned, ARM and Thumb2 are 4-byte
+ // aligned.
+ AFI->setAlign(isThumb1 ? 1U : 2U);
// Perform the initial placement of the constant pool entries. To start with,
// we put them all at the end of the function.
std::vector<MachineInstr*> CPEMIs;
if (!MCP.isEmpty()) {
- DoInitialPlacement(Fn, CPEMIs);
- if (isThumb)
+ DoInitialPlacement(MF, CPEMIs);
+ if (isThumb1)
AFI->setAlign(2U);
}
@@ -242,7 +268,7 @@ bool ARMConstantIslands::runOnMachineFunction(MachineFunction &Fn) {
// Do the initial scan of the function, building up information about the
// sizes of each block, the location of all the water, and finding all of the
// constant pool users.
- InitialFunctionScan(Fn, CPEMIs);
+ InitialFunctionScan(MF, CPEMIs);
CPEMIs.clear();
/// Remove dead constant pool entries.
@@ -251,25 +277,37 @@ bool ARMConstantIslands::runOnMachineFunction(MachineFunction &Fn) {
// Iteratively place constant pool entries and fix up branches until there
// is no change.
bool MadeChange = false;
+ unsigned NoCPIters = 0, NoBRIters = 0;
while (true) {
- bool Change = false;
+ bool CPChange = false;
for (unsigned i = 0, e = CPUsers.size(); i != e; ++i)
- Change |= HandleConstantPoolUser(Fn, i);
+ CPChange |= HandleConstantPoolUser(MF, i);
+ if (CPChange && ++NoCPIters > 30)
+ llvm_unreachable("Constant Island pass failed to converge!");
DEBUG(dumpBBs());
+
+ bool BRChange = false;
for (unsigned i = 0, e = ImmBranches.size(); i != e; ++i)
- Change |= FixUpImmediateBr(Fn, ImmBranches[i]);
+ BRChange |= FixUpImmediateBr(MF, ImmBranches[i]);
+ if (BRChange && ++NoBRIters > 30)
+ llvm_unreachable("Branch Fix Up pass failed to converge!");
DEBUG(dumpBBs());
- if (!Change)
+
+ if (!CPChange && !BRChange)
break;
MadeChange = true;
}
+ // Shrink 32-bit Thumb2 branch, load, and store instructions.
+ if (isThumb2)
+ MadeChange |= OptimizeThumb2Instructions(MF);
+
// After a while, this might be made debug-only, but it is not expensive.
- verify(Fn);
+ verify(MF);
// If LR has been forced spilled and no far jumps (i.e. BL) has been issued.
// Undo the spill / restore of LR if possible.
- if (!HasFarJump && AFI->isLRSpilledForFarJump() && isThumb)
+ if (isThumb && !HasFarJump && AFI->isLRSpilledForFarJump())
MadeChange |= UndoLRSpillRestore();
BBSizes.clear();
@@ -279,24 +317,25 @@ bool ARMConstantIslands::runOnMachineFunction(MachineFunction &Fn) {
CPEntries.clear();
ImmBranches.clear();
PushPopMIs.clear();
+ T2JumpTables.clear();
return MadeChange;
}
/// DoInitialPlacement - Perform the initial placement of the constant pool
/// entries. To start with, we put them all at the end of the function.
-void ARMConstantIslands::DoInitialPlacement(MachineFunction &Fn,
+void ARMConstantIslands::DoInitialPlacement(MachineFunction &MF,
std::vector<MachineInstr*> &CPEMIs) {
// Create the basic block to hold the CPE's.
- MachineBasicBlock *BB = Fn.CreateMachineBasicBlock();
- Fn.push_back(BB);
+ MachineBasicBlock *BB = MF.CreateMachineBasicBlock();
+ MF.push_back(BB);
// Add all of the constants from the constant pool to the end block, use an
// identity mapping of CPI's to CPE's.
const std::vector<MachineConstantPoolEntry> &CPs =
- Fn.getConstantPool()->getConstants();
+ MF.getConstantPool()->getConstants();
- const TargetData &TD = *Fn.getTarget().getTargetData();
+ const TargetData &TD = *MF.getTarget().getTargetData();
for (unsigned i = 0, e = CPs.size(); i != e; ++i) {
unsigned Size = TD.getTypeAllocSize(CPs[i].getType());
// Verify that all constant pool entries are a multiple of 4 bytes. If not,
@@ -313,7 +352,8 @@ void ARMConstantIslands::DoInitialPlacement(MachineFunction &Fn,
CPEs.push_back(CPEntry(CPEMI, i));
CPEntries.push_back(CPEs);
NumCPEs++;
- DOUT << "Moved CPI#" << i << " to end of function as #" << i << "\n";
+ DEBUG(errs() << "Moved CPI#" << i << " to end of function as #" << i
+ << "\n");
}
}
@@ -352,10 +392,10 @@ ARMConstantIslands::CPEntry
/// InitialFunctionScan - Do the initial scan of the function, building up
/// information about the sizes of each block, the location of all the water,
/// and finding all of the constant pool users.
-void ARMConstantIslands::InitialFunctionScan(MachineFunction &Fn,
+void ARMConstantIslands::InitialFunctionScan(MachineFunction &MF,
const std::vector<MachineInstr*> &CPEMIs) {
unsigned Offset = 0;
- for (MachineFunction::iterator MBBI = Fn.begin(), E = Fn.end();
+ for (MachineFunction::iterator MBBI = MF.begin(), E = MF.end();
MBBI != E; ++MBBI) {
MachineBasicBlock &MBB = *MBBI;
@@ -377,18 +417,19 @@ void ARMConstantIslands::InitialFunctionScan(MachineFunction &Fn,
unsigned Scale = 1;
int UOpc = Opc;
switch (Opc) {
+ default:
+ continue; // Ignore other JT branches
case ARM::tBR_JTr:
- case ARM::t2BR_JTr:
- case ARM::t2BR_JTm:
- case ARM::t2BR_JTadd:
- // A Thumb table jump may involve padding; for the offsets to
+ // A Thumb1 table jump may involve padding; for the offsets to
// be right, functions containing these must be 4-byte aligned.
AFI->setAlign(2U);
if ((Offset+MBBSize)%4 != 0)
+ // FIXME: Add a pseudo ALIGN instruction instead.
MBBSize += 2; // padding
continue; // Does not get an entry in ImmBranches
- default:
- continue; // Ignore other JT branches
+ case ARM::t2BR_JT:
+ T2JumpTables.push_back(I);
+ continue; // Does not get an entry in ImmBranches
case ARM::Bcc:
isCond = true;
UOpc = ARM::B;
@@ -427,6 +468,9 @@ void ARMConstantIslands::InitialFunctionScan(MachineFunction &Fn,
if (Opc == ARM::tPUSH || Opc == ARM::tPOP_RET)
PushPopMIs.push_back(I);
+ if (Opc == ARM::CONSTPOOL_ENTRY)
+ continue;
+
// Scan the instructions for constant pool operands.
for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op)
if (I->getOperand(op).isCPI()) {
@@ -436,50 +480,52 @@ void ARMConstantIslands::InitialFunctionScan(MachineFunction &Fn,
// Basic size info comes from the TSFlags field.
unsigned Bits = 0;
unsigned Scale = 1;
- unsigned TSFlags = I->getDesc().TSFlags;
- switch (TSFlags & ARMII::AddrModeMask) {
+ bool NegOk = false;
+ bool IsSoImm = false;
+
+ switch (Opc) {
default:
- // Constant pool entries can reach anything.
- if (I->getOpcode() == ARM::CONSTPOOL_ENTRY)
- continue;
- if (I->getOpcode() == ARM::tLEApcrel) {
- Bits = 8; // Taking the address of a CP entry.
- break;
- }
- assert(0 && "Unknown addressing mode for CP reference!");
- case ARMII::AddrMode1: // AM1: 8 bits << 2
- Bits = 8;
- Scale = 4; // Taking the address of a CP entry.
- break;
- case ARMII::AddrMode2:
- Bits = 12; // +-offset_12
- break;
- case ARMII::AddrMode3:
- Bits = 8; // +-offset_8
+ llvm_unreachable("Unknown addressing mode for CP reference!");
break;
- // addrmode4 has no immediate offset.
- case ARMII::AddrMode5:
+
+ // Taking the address of a CP entry.
+ case ARM::LEApcrel:
+ // This takes a SoImm, which is 8 bit immediate rotated. We'll
+ // pretend the maximum offset is 255 * 4. Since each instruction
+ // 4 byte wide, this is always correct. We'llc heck for other
+ // displacements that fits in a SoImm as well.
Bits = 8;
- Scale = 4; // +-(offset_8*4)
+ Scale = 4;
+ NegOk = true;
+ IsSoImm = true;
break;
- // addrmode6 has no immediate offset.
- case ARMII::AddrModeT1_1:
- Bits = 5; // +offset_5
+ case ARM::t2LEApcrel:
+ Bits = 12;
+ NegOk = true;
break;
- case ARMII::AddrModeT1_2:
- Bits = 5;
- Scale = 2; // +(offset_5*2)
+ case ARM::tLEApcrel:
+ Bits = 8;
+ Scale = 4;
break;
- case ARMII::AddrModeT1_4:
- Bits = 5;
- Scale = 4; // +(offset_5*4)
+
+ case ARM::LDR:
+ case ARM::LDRcp:
+ case ARM::t2LDRpci:
+ Bits = 12; // +-offset_12
+ NegOk = true;
break;
- case ARMII::AddrModeT1_s:
+
+ case ARM::tLDRpci:
+ case ARM::tLDRcp:
Bits = 8;
Scale = 4; // +(offset_8*4)
break;
- case ARMII::AddrModeT2_pc:
- Bits = 12; // +-offset_12
+
+ case ARM::FLDD:
+ case ARM::FLDS:
+ Bits = 8;
+ Scale = 4; // +-(offset_8*4)
+ NegOk = true;
break;
}
@@ -487,7 +533,7 @@ void ARMConstantIslands::InitialFunctionScan(MachineFunction &Fn,
unsigned CPI = I->getOperand(op).getIndex();
MachineInstr *CPEMI = CPEMIs[CPI];
unsigned MaxOffs = ((1 << Bits)-1) * Scale;
- CPUsers.push_back(CPUser(I, CPEMI, MaxOffs));
+ CPUsers.push_back(CPUser(I, CPEMI, MaxOffs, NegOk, IsSoImm));
// Increment corresponding CPEntry reference count.
CPEntry *CPE = findConstPoolEntry(CPI, CPEMI);
@@ -563,7 +609,7 @@ void ARMConstantIslands::UpdateForInsertedWaterBlock(MachineBasicBlock *NewBB) {
// Next, update WaterList. Specifically, we need to add NewMBB as having
// available water after it.
- std::vector<MachineBasicBlock*>::iterator IP =
+ water_iterator IP =
std::lower_bound(WaterList.begin(), WaterList.end(), NewBB,
CompareMBBNumbers);
WaterList.insert(IP, NewBB);
@@ -590,8 +636,8 @@ MachineBasicBlock *ARMConstantIslands::SplitBlockBeforeInstr(MachineInstr *MI) {
// Note the new unconditional branch is not being recorded.
// There doesn't seem to be meaningful DebugInfo available; this doesn't
// correspond to anything in the source.
- BuildMI(OrigBB, DebugLoc::getUnknownLoc(),
- TII->get(isThumb ? ((isThumb2) ? ARM::t2B : ARM::tB) : ARM::B)).addMBB(NewBB);
+ unsigned Opc = isThumb ? (isThumb2 ? ARM::t2B : ARM::tB) : ARM::B;
+ BuildMI(OrigBB, DebugLoc::getUnknownLoc(), TII->get(Opc)).addMBB(NewBB);
NumSplit++;
// Update the CFG. All succs of OrigBB are now succs of NewBB.
@@ -625,7 +671,7 @@ MachineBasicBlock *ARMConstantIslands::SplitBlockBeforeInstr(MachineInstr *MI) {
// available water after it (but not if it's already there, which happens
// when splitting before a conditional branch that is followed by an
// unconditional branch - in that case we want to insert NewBB).
- std::vector<MachineBasicBlock*>::iterator IP =
+ water_iterator IP =
std::lower_bound(WaterList.begin(), WaterList.end(), OrigBB,
CompareMBBNumbers);
MachineBasicBlock* WaterBB = *IP;
@@ -648,7 +694,7 @@ MachineBasicBlock *ARMConstantIslands::SplitBlockBeforeInstr(MachineInstr *MI) {
// We removed instructions from UserMBB, subtract that off from its size.
// Add 2 or 4 to the block to count the unconditional branch we added to it.
- unsigned delta = isThumb ? 2 : 4;
+ int delta = isThumb1 ? 2 : 4;
BBSizes[OrigBBI] -= NewBBSize - delta;
// ...and adjust BBOffsets for NewBB accordingly.
@@ -664,24 +710,39 @@ MachineBasicBlock *ARMConstantIslands::SplitBlockBeforeInstr(MachineInstr *MI) {
/// reference) is within MaxDisp of TrialOffset (a proposed location of a
/// constant pool entry).
bool ARMConstantIslands::OffsetIsInRange(unsigned UserOffset,
- unsigned TrialOffset, unsigned MaxDisp, bool NegativeOK) {
+ unsigned TrialOffset, unsigned MaxDisp,
+ bool NegativeOK, bool IsSoImm) {
// On Thumb offsets==2 mod 4 are rounded down by the hardware for
// purposes of the displacement computation; compensate for that here.
// Effectively, the valid range of displacements is 2 bytes smaller for such
// references.
- if (isThumb && UserOffset%4 !=0)
+ unsigned TotalAdj = 0;
+ if (isThumb && UserOffset%4 !=0) {
UserOffset -= 2;
+ TotalAdj = 2;
+ }
// CPEs will be rounded up to a multiple of 4.
- if (isThumb && TrialOffset%4 != 0)
+ if (isThumb && TrialOffset%4 != 0) {
TrialOffset += 2;
+ TotalAdj += 2;
+ }
+
+ // In Thumb2 mode, later branch adjustments can shift instructions up and
+ // cause alignment change. In the worst case scenario this can cause the
+ // user's effective address to be subtracted by 2 and the CPE's address to
+ // be plus 2.
+ if (isThumb2 && TotalAdj != 4)
+ MaxDisp -= (4 - TotalAdj);
if (UserOffset <= TrialOffset) {
// User before the Trial.
- if (TrialOffset-UserOffset <= MaxDisp)
+ if (TrialOffset - UserOffset <= MaxDisp)
return true;
+ // FIXME: Make use full range of soimm values.
} else if (NegativeOK) {
- if (UserOffset-TrialOffset <= MaxDisp)
+ if (UserOffset - TrialOffset <= MaxDisp)
return true;
+ // FIXME: Make use full range of soimm values.
}
return false;
}
@@ -690,39 +751,36 @@ bool ARMConstantIslands::OffsetIsInRange(unsigned UserOffset,
/// Water (a basic block) will be in range for the specific MI.
bool ARMConstantIslands::WaterIsInRange(unsigned UserOffset,
- MachineBasicBlock* Water, CPUser &U)
-{
+ MachineBasicBlock* Water, CPUser &U) {
unsigned MaxDisp = U.MaxDisp;
- MachineFunction::iterator I = next(MachineFunction::iterator(Water));
unsigned CPEOffset = BBOffsets[Water->getNumber()] +
BBSizes[Water->getNumber()];
// If the CPE is to be inserted before the instruction, that will raise
- // the offset of the instruction. (Currently applies only to ARM, so
- // no alignment compensation attempted here.)
+ // the offset of the instruction.
if (CPEOffset < UserOffset)
UserOffset += U.CPEMI->getOperand(2).getImm();
- return OffsetIsInRange (UserOffset, CPEOffset, MaxDisp, !isThumb);
+ return OffsetIsInRange(UserOffset, CPEOffset, MaxDisp, U.NegOk, U.IsSoImm);
}
/// CPEIsInRange - Returns true if the distance between specific MI and
/// specific ConstPool entry instruction can fit in MI's displacement field.
bool ARMConstantIslands::CPEIsInRange(MachineInstr *MI, unsigned UserOffset,
- MachineInstr *CPEMI,
- unsigned MaxDisp, bool DoDump) {
+ MachineInstr *CPEMI, unsigned MaxDisp,
+ bool NegOk, bool DoDump) {
unsigned CPEOffset = GetOffsetOf(CPEMI);
assert(CPEOffset%4 == 0 && "Misaligned CPE");
if (DoDump) {
- DOUT << "User of CPE#" << CPEMI->getOperand(0).getImm()
- << " max delta=" << MaxDisp
- << " insn address=" << UserOffset
- << " CPE address=" << CPEOffset
- << " offset=" << int(CPEOffset-UserOffset) << "\t" << *MI;
+ DEBUG(errs() << "User of CPE#" << CPEMI->getOperand(0).getImm()
+ << " max delta=" << MaxDisp
+ << " insn address=" << UserOffset
+ << " CPE address=" << CPEOffset
+ << " offset=" << int(CPEOffset-UserOffset) << "\t" << *MI);
}
- return OffsetIsInRange(UserOffset, CPEOffset, MaxDisp, !isThumb);
+ return OffsetIsInRange(UserOffset, CPEOffset, MaxDisp, NegOk);
}
#ifndef NDEBUG
@@ -745,52 +803,48 @@ static bool BBIsJumpedOver(MachineBasicBlock *MBB) {
void ARMConstantIslands::AdjustBBOffsetsAfter(MachineBasicBlock *BB,
int delta) {
MachineFunction::iterator MBBI = BB; MBBI = next(MBBI);
- for(unsigned i=BB->getNumber()+1; i<BB->getParent()->getNumBlockIDs(); i++) {
+ for(unsigned i = BB->getNumber()+1, e = BB->getParent()->getNumBlockIDs();
+ i < e; ++i) {
BBOffsets[i] += delta;
// If some existing blocks have padding, adjust the padding as needed, a
// bit tricky. delta can be negative so don't use % on that.
- if (isThumb) {
- MachineBasicBlock *MBB = MBBI;
- if (!MBB->empty()) {
- // Constant pool entries require padding.
- if (MBB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY) {
- unsigned oldOffset = BBOffsets[i] - delta;
- if (oldOffset%4==0 && BBOffsets[i]%4!=0) {
- // add new padding
- BBSizes[i] += 2;
- delta += 2;
- } else if (oldOffset%4!=0 && BBOffsets[i]%4==0) {
- // remove existing padding
- BBSizes[i] -=2;
- delta -= 2;
- }
+ if (!isThumb)
+ continue;
+ MachineBasicBlock *MBB = MBBI;
+ if (!MBB->empty()) {
+ // Constant pool entries require padding.
+ if (MBB->begin()->getOpcode() == ARM::CONSTPOOL_ENTRY) {
+ unsigned OldOffset = BBOffsets[i] - delta;
+ if ((OldOffset%4) == 0 && (BBOffsets[i]%4) != 0) {
+ // add new padding
+ BBSizes[i] += 2;
+ delta += 2;
+ } else if ((OldOffset%4) != 0 && (BBOffsets[i]%4) == 0) {
+ // remove existing padding
+ BBSizes[i] -= 2;
+ delta -= 2;
}
- // Thumb jump tables require padding. They should be at the end;
- // following unconditional branches are removed by AnalyzeBranch.
- MachineInstr *ThumbJTMI = NULL;
- if ((prior(MBB->end())->getOpcode() == ARM::tBR_JTr)
- || (prior(MBB->end())->getOpcode() == ARM::t2BR_JTr)
- || (prior(MBB->end())->getOpcode() == ARM::t2BR_JTm)
- || (prior(MBB->end())->getOpcode() == ARM::t2BR_JTadd))
- ThumbJTMI = prior(MBB->end());
- if (ThumbJTMI) {
- unsigned newMIOffset = GetOffsetOf(ThumbJTMI);
- unsigned oldMIOffset = newMIOffset - delta;
- if (oldMIOffset%4 == 0 && newMIOffset%4 != 0) {
- // remove existing padding
- BBSizes[i] -= 2;
- delta -= 2;
- } else if (oldMIOffset%4 != 0 && newMIOffset%4 == 0) {
- // add new padding
- BBSizes[i] += 2;
- delta += 2;
- }
+ }
+ // Thumb1 jump tables require padding. They should be at the end;
+ // following unconditional branches are removed by AnalyzeBranch.
+ MachineInstr *ThumbJTMI = prior(MBB->end());
+ if (ThumbJTMI->getOpcode() == ARM::tBR_JTr) {
+ unsigned NewMIOffset = GetOffsetOf(ThumbJTMI);
+ unsigned OldMIOffset = NewMIOffset - delta;
+ if ((OldMIOffset%4) == 0 && (NewMIOffset%4) != 0) {
+ // remove existing padding
+ BBSizes[i] -= 2;
+ delta -= 2;
+ } else if ((OldMIOffset%4) != 0 && (NewMIOffset%4) == 0) {
+ // add new padding
+ BBSizes[i] += 2;
+ delta += 2;
}
- if (delta==0)
- return;
}
- MBBI = next(MBBI);
+ if (delta==0)
+ return;
}
+ MBBI = next(MBBI);
}
}
@@ -824,8 +878,8 @@ int ARMConstantIslands::LookForExistingCPEntry(CPUser& U, unsigned UserOffset)
MachineInstr *CPEMI = U.CPEMI;
// Check to see if the CPE is already in-range.
- if (CPEIsInRange(UserMI, UserOffset, CPEMI, U.MaxDisp, true)) {
- DOUT << "In range\n";
+ if (CPEIsInRange(UserMI, UserOffset, CPEMI, U.MaxDisp, U.NegOk, true)) {
+ DEBUG(errs() << "In range\n");
return 1;
}
@@ -839,8 +893,9 @@ int ARMConstantIslands::LookForExistingCPEntry(CPUser& U, unsigned UserOffset)
// Removing CPEs can leave empty entries, skip
if (CPEs[i].CPEMI == NULL)
continue;
- if (CPEIsInRange(UserMI, UserOffset, CPEs[i].CPEMI, U.MaxDisp, false)) {
- DOUT << "Replacing CPE#" << CPI << " with CPE#" << CPEs[i].CPI << "\n";
+ if (CPEIsInRange(UserMI, UserOffset, CPEs[i].CPEMI, U.MaxDisp, U.NegOk)) {
+ DEBUG(errs() << "Replacing CPE#" << CPI << " with CPE#"
+ << CPEs[i].CPI << "\n");
// Point the CPUser node to the replacement
U.CPEMI = CPEs[i].CPEMI;
// Change the CPI in the instruction operand to refer to the clone.
@@ -870,15 +925,15 @@ static inline unsigned getUnconditionalBrDisp(int Opc) {
default:
break;
}
-
+
return ((1<<23)-1)*4;
}
/// AcceptWater - Small amount of common code factored out of the following.
-
-MachineBasicBlock* ARMConstantIslands::AcceptWater(MachineBasicBlock *WaterBB,
- std::vector<MachineBasicBlock*>::iterator IP) {
- DOUT << "found water in range\n";
+///
+MachineBasicBlock *ARMConstantIslands::AcceptWater(water_iterator IP) {
+ DEBUG(errs() << "found water in range\n");
+ MachineBasicBlock *WaterBB = *IP;
// Remove the original WaterList entry; we want subsequent
// insertions in this vicinity to go after the one we're
// about to insert. This considerably reduces the number
@@ -890,41 +945,44 @@ MachineBasicBlock* ARMConstantIslands::AcceptWater(MachineBasicBlock *WaterBB,
/// LookForWater - look for an existing entry in the WaterList in which
/// we can place the CPE referenced from U so it's within range of U's MI.
-/// Returns true if found, false if not. If it returns true, *NewMBB
-/// is set to the WaterList entry.
-/// For ARM, we prefer the water that's farthest away. For Thumb, prefer
-/// water that will not introduce padding to water that will; within each
-/// group, prefer the water that's farthest away.
-
+/// Returns true if found, false if not. If it returns true, NewMBB
+/// is set to the WaterList entry. For Thumb, prefer water that will not
+/// introduce padding to water that will. To ensure that this pass
+/// terminates, the CPE location for a particular CPUser is only allowed to
+/// move to a lower address, so search backward from the end of the list and
+/// prefer the first water that is in range.
bool ARMConstantIslands::LookForWater(CPUser &U, unsigned UserOffset,
- MachineBasicBlock** NewMBB) {
- std::vector<MachineBasicBlock*>::iterator IPThatWouldPad;
- MachineBasicBlock* WaterBBThatWouldPad = NULL;
- if (!WaterList.empty()) {
- for (std::vector<MachineBasicBlock*>::iterator IP = prior(WaterList.end()),
- B = WaterList.begin();; --IP) {
- MachineBasicBlock* WaterBB = *IP;
- if (WaterIsInRange(UserOffset, WaterBB, U)) {
- if (isThumb &&
- (BBOffsets[WaterBB->getNumber()] +
- BBSizes[WaterBB->getNumber()])%4 != 0) {
- // This is valid Water, but would introduce padding. Remember
- // it in case we don't find any Water that doesn't do this.
- if (!WaterBBThatWouldPad) {
- WaterBBThatWouldPad = WaterBB;
- IPThatWouldPad = IP;
- }
- } else {
- *NewMBB = AcceptWater(WaterBB, IP);
- return true;
+ MachineBasicBlock *&NewMBB) {
+ if (WaterList.empty())
+ return false;
+
+ bool FoundWaterThatWouldPad = false;
+ water_iterator IPThatWouldPad;
+ for (water_iterator IP = prior(WaterList.end()),
+ B = WaterList.begin();; --IP) {
+ MachineBasicBlock* WaterBB = *IP;
+ // Check if water is in range and at a lower address than the current one.
+ if (WaterIsInRange(UserOffset, WaterBB, U) &&
+ WaterBB->getNumber() < U.CPEMI->getParent()->getNumber()) {
+ unsigned WBBId = WaterBB->getNumber();
+ if (isThumb &&
+ (BBOffsets[WBBId] + BBSizes[WBBId])%4 != 0) {
+ // This is valid Water, but would introduce padding. Remember
+ // it in case we don't find any Water that doesn't do this.
+ if (!FoundWaterThatWouldPad) {
+ FoundWaterThatWouldPad = true;
+ IPThatWouldPad = IP;
}
+ } else {
+ NewMBB = AcceptWater(IP);
+ return true;
+ }
}
- if (IP == B)
- break;
- }
+ if (IP == B)
+ break;
}
- if (isThumb && WaterBBThatWouldPad) {
- *NewMBB = AcceptWater(WaterBBThatWouldPad, IPThatWouldPad);
+ if (FoundWaterThatWouldPad) {
+ NewMBB = AcceptWater(IPThatWouldPad);
return true;
}
return false;
@@ -934,12 +992,12 @@ bool ARMConstantIslands::LookForWater(CPUser &U, unsigned UserOffset,
/// CPUsers[CPUserIndex], so create a place to put the CPE. The end of the
/// block is used if in range, and the conditional branch munged so control
/// flow is correct. Otherwise the block is split to create a hole with an
-/// unconditional branch around it. In either case *NewMBB is set to a
+/// unconditional branch around it. In either case NewMBB is set to a
/// block following which the new island can be inserted (the WaterList
/// is not adjusted).
-
void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
- unsigned UserOffset, MachineBasicBlock** NewMBB) {
+ unsigned UserOffset,
+ MachineBasicBlock *&NewMBB) {
CPUser &U = CPUsers[CPUserIndex];
MachineInstr *UserMI = U.MI;
MachineInstr *CPEMI = U.CPEMI;
@@ -950,18 +1008,18 @@ void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
// If the use is at the end of the block, or the end of the block
// is within range, make new water there. (The addition below is
- // for the unconditional branch we will be adding: 4 bytes on ARM,
- // 2 on Thumb. Possible Thumb alignment padding is allowed for
+ // for the unconditional branch we will be adding: 4 bytes on ARM + Thumb2,
+ // 2 on Thumb1. Possible Thumb1 alignment padding is allowed for
// inside OffsetIsInRange.
// If the block ends in an unconditional branch already, it is water,
// and is known to be out of range, so we'll always be adding a branch.)
if (&UserMBB->back() == UserMI ||
- OffsetIsInRange(UserOffset, OffsetOfNextBlock + (isThumb ? 2: 4),
- U.MaxDisp, !isThumb)) {
- DOUT << "Split at end of block\n";
+ OffsetIsInRange(UserOffset, OffsetOfNextBlock + (isThumb1 ? 2: 4),
+ U.MaxDisp, U.NegOk, U.IsSoImm)) {
+ DEBUG(errs() << "Split at end of block\n");
if (&UserMBB->back() == UserMI)
assert(BBHasFallthrough(UserMBB) && "Expected a fallthrough BB!");
- *NewMBB = next(MachineFunction::iterator(UserMBB));
+ NewMBB = next(MachineFunction::iterator(UserMBB));
// Add an unconditional branch from UserMBB to fallthrough block.
// Record it for branch lengthening; this new branch will not get out of
// range, but if the preceding conditional branch is out of range, the
@@ -969,16 +1027,16 @@ void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
// range, so the machinery has to know about it.
int UncondBr = isThumb ? ((isThumb2) ? ARM::t2B : ARM::tB) : ARM::B;
BuildMI(UserMBB, DebugLoc::getUnknownLoc(),
- TII->get(UncondBr)).addMBB(*NewMBB);
+ TII->get(UncondBr)).addMBB(NewMBB);
unsigned MaxDisp = getUnconditionalBrDisp(UncondBr);
ImmBranches.push_back(ImmBranch(&UserMBB->back(),
MaxDisp, false, UncondBr));
- int delta = isThumb ? 2 : 4;
+ int delta = isThumb1 ? 2 : 4;
BBSizes[UserMBB->getNumber()] += delta;
AdjustBBOffsetsAfter(UserMBB, delta);
} else {
// What a big block. Find a place within the block to split it.
- // This is a little tricky on Thumb since instructions are 2 bytes
+ // This is a little tricky on Thumb1 since instructions are 2 bytes
// and constant pool entries are 4 bytes: if instruction I references
// island CPE, and instruction I+1 references CPE', it will
// not work well to put CPE as far forward as possible, since then
@@ -991,7 +1049,7 @@ void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
// if not, we back up the insertion point.
// The 4 in the following is for the unconditional branch we'll be
- // inserting (allows for long branch on Thumb). Alignment of the
+ // inserting (allows for long branch on Thumb1). Alignment of the
// island is handled inside OffsetIsInRange.
unsigned BaseInsertOffset = UserOffset + U.MaxDisp -4;
// This could point off the end of the block if we've already got
@@ -1000,7 +1058,7 @@ void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
// conditional and a maximally long unconditional).
if (BaseInsertOffset >= BBOffsets[UserMBB->getNumber()+1])
BaseInsertOffset = BBOffsets[UserMBB->getNumber()+1] -
- (isThumb ? 6 : 8);
+ (isThumb1 ? 6 : 8);
unsigned EndInsertOffset = BaseInsertOffset +
CPEMI->getOperand(2).getImm();
MachineBasicBlock::iterator MI = UserMI;
@@ -1011,10 +1069,11 @@ void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
Offset += TII->GetInstSizeInBytes(MI),
MI = next(MI)) {
if (CPUIndex < CPUsers.size() && CPUsers[CPUIndex].MI == MI) {
+ CPUser &U = CPUsers[CPUIndex];
if (!OffsetIsInRange(Offset, EndInsertOffset,
- CPUsers[CPUIndex].MaxDisp, !isThumb)) {
- BaseInsertOffset -= (isThumb ? 2 : 4);
- EndInsertOffset -= (isThumb ? 2 : 4);
+ U.MaxDisp, U.NegOk, U.IsSoImm)) {
+ BaseInsertOffset -= (isThumb1 ? 2 : 4);
+ EndInsertOffset -= (isThumb1 ? 2 : 4);
}
// This is overly conservative, as we don't account for CPEMIs
// being reused within the block, but it doesn't matter much.
@@ -1022,8 +1081,8 @@ void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
CPUIndex++;
}
}
- DOUT << "Split in middle of big block\n";
- *NewMBB = SplitBlockBeforeInstr(prior(MI));
+ DEBUG(errs() << "Split in middle of big block\n");
+ NewMBB = SplitBlockBeforeInstr(prior(MI));
}
}
@@ -1031,7 +1090,7 @@ void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
/// is out-of-range. If so, pick up the constant pool value and move it some
/// place in-range. Return true if we changed any addresses (thus must run
/// another pass of branch lengthening), false otherwise.
-bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &Fn,
+bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &MF,
unsigned CPUserIndex) {
CPUser &U = CPUsers[CPUserIndex];
MachineInstr *UserMI = U.MI;
@@ -1040,14 +1099,9 @@ bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &Fn,
unsigned Size = CPEMI->getOperand(2).getImm();
MachineBasicBlock *NewMBB;
// Compute this only once, it's expensive. The 4 or 8 is the value the
- // hardware keeps in the PC (2 insns ahead of the reference).
+ // hardware keeps in the PC.
unsigned UserOffset = GetOffsetOf(UserMI) + (isThumb ? 4 : 8);
- // Special case: tLEApcrel are two instructions MI's. The actual user is the
- // second instruction.
- if (UserMI->getOpcode() == ARM::tLEApcrel)
- UserOffset += 2;
-
// See if the current entry is within range, or there is a clone of it
// in range.
int result = LookForExistingCPEntry(U, UserOffset);
@@ -1058,19 +1112,16 @@ bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &Fn,
// We will be generating a new clone. Get a UID for it.
unsigned ID = AFI->createConstPoolEntryUId();
- // Look for water where we can place this CPE. We look for the farthest one
- // away that will work. Forward references only for now (although later
- // we might find some that are backwards).
-
- if (!LookForWater(U, UserOffset, &NewMBB)) {
+ // Look for water where we can place this CPE.
+ if (!LookForWater(U, UserOffset, NewMBB)) {
// No water found.
- DOUT << "No water found\n";
- CreateNewWater(CPUserIndex, UserOffset, &NewMBB);
+ DEBUG(errs() << "No water found\n");
+ CreateNewWater(CPUserIndex, UserOffset, NewMBB);
}
// Okay, we know we can put an island before NewMBB now, do it!
- MachineBasicBlock *NewIsland = Fn.CreateMachineBasicBlock();
- Fn.insert(NewMBB, NewIsland);
+ MachineBasicBlock *NewIsland = MF.CreateMachineBasicBlock();
+ MF.insert(NewMBB, NewIsland);
// Update internal data structures to account for the newly inserted MBB.
UpdateForInsertedWaterBlock(NewIsland);
@@ -1101,7 +1152,8 @@ bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &Fn,
break;
}
- DOUT << " Moved CPE to #" << ID << " CPI=" << CPI << "\t" << *UserMI;
+ DEBUG(errs() << " Moved CPE to #" << ID << " CPI=" << CPI
+ << '\t' << *UserMI);
return true;
}
@@ -1115,7 +1167,7 @@ void ARMConstantIslands::RemoveDeadCPEMI(MachineInstr *CPEMI) {
BBSizes[CPEBB->getNumber()] -= Size;
// All succeeding offsets have the current size value added in, fix this.
if (CPEBB->empty()) {
- // In thumb mode, the size of island may be padded by two to compensate for
+ // In thumb1 mode, the size of island may be padded by two to compensate for
// the alignment requirement. Then it will now be 2 when the block is
// empty, so fix this.
// All succeeding offsets have the current size value added in, fix this.
@@ -1157,11 +1209,11 @@ bool ARMConstantIslands::BBIsInRange(MachineInstr *MI,MachineBasicBlock *DestBB,
unsigned BrOffset = GetOffsetOf(MI) + PCAdj;
unsigned DestOffset = BBOffsets[DestBB->getNumber()];
- DOUT << "Branch of destination BB#" << DestBB->getNumber()
- << " from BB#" << MI->getParent()->getNumber()
- << " max delta=" << MaxDisp
- << " from " << GetOffsetOf(MI) << " to " << DestOffset
- << " offset " << int(DestOffset-BrOffset) << "\t" << *MI;
+ DEBUG(errs() << "Branch of destination BB#" << DestBB->getNumber()
+ << " from BB#" << MI->getParent()->getNumber()
+ << " max delta=" << MaxDisp
+ << " from " << GetOffsetOf(MI) << " to " << DestOffset
+ << " offset " << int(DestOffset-BrOffset) << "\t" << *MI);
if (BrOffset <= DestOffset) {
// Branch before the Dest.
@@ -1176,7 +1228,7 @@ bool ARMConstantIslands::BBIsInRange(MachineInstr *MI,MachineBasicBlock *DestBB,
/// FixUpImmediateBr - Fix up an immediate branch whose destination is too far
/// away to fit in its displacement field.
-bool ARMConstantIslands::FixUpImmediateBr(MachineFunction &Fn, ImmBranch &Br) {
+bool ARMConstantIslands::FixUpImmediateBr(MachineFunction &MF, ImmBranch &Br) {
MachineInstr *MI = Br.MI;
MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
@@ -1185,8 +1237,8 @@ bool ARMConstantIslands::FixUpImmediateBr(MachineFunction &Fn, ImmBranch &Br) {
return false;
if (!Br.isCond)
- return FixUpUnconditionalBr(Fn, Br);
- return FixUpConditionalBr(Fn, Br);
+ return FixUpUnconditionalBr(MF, Br);
+ return FixUpConditionalBr(MF, Br);
}
/// FixUpUnconditionalBr - Fix up an unconditional branch whose destination is
@@ -1194,10 +1246,11 @@ bool ARMConstantIslands::FixUpImmediateBr(MachineFunction &Fn, ImmBranch &Br) {
/// spilled in the epilogue, then we can use BL to implement a far jump.
/// Otherwise, add an intermediate branch instruction to a branch.
bool
-ARMConstantIslands::FixUpUnconditionalBr(MachineFunction &Fn, ImmBranch &Br) {
+ARMConstantIslands::FixUpUnconditionalBr(MachineFunction &MF, ImmBranch &Br) {
MachineInstr *MI = Br.MI;
MachineBasicBlock *MBB = MI->getParent();
- assert(isThumb && !isThumb2 && "Expected a Thumb-1 function!");
+ if (!isThumb1)
+ llvm_unreachable("FixUpUnconditionalBr is Thumb1 only!");
// Use BL to implement far jump.
Br.MaxDisp = (1 << 21) * 2;
@@ -1207,7 +1260,7 @@ ARMConstantIslands::FixUpUnconditionalBr(MachineFunction &Fn, ImmBranch &Br) {
HasFarJump = true;
NumUBrFixed++;
- DOUT << " Changed B to long jump " << *MI;
+ DEBUG(errs() << " Changed B to long jump " << *MI);
return true;
}
@@ -1216,7 +1269,7 @@ ARMConstantIslands::FixUpUnconditionalBr(MachineFunction &Fn, ImmBranch &Br) {
/// far away to fit in its displacement field. It is converted to an inverse
/// conditional branch + an unconditional branch to the destination.
bool
-ARMConstantIslands::FixUpConditionalBr(MachineFunction &Fn, ImmBranch &Br) {
+ARMConstantIslands::FixUpConditionalBr(MachineFunction &MF, ImmBranch &Br) {
MachineInstr *MI = Br.MI;
MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
@@ -1251,7 +1304,8 @@ ARMConstantIslands::FixUpConditionalBr(MachineFunction &Fn, ImmBranch &Br) {
// b L1
MachineBasicBlock *NewDest = BMI->getOperand(0).getMBB();
if (BBIsInRange(MI, NewDest, Br.MaxDisp)) {
- DOUT << " Invert Bcc condition and swap its destination with " << *BMI;
+ DEBUG(errs() << " Invert Bcc condition and swap its destination with "
+ << *BMI);
BMI->getOperand(0).setMBB(DestBB);
MI->getOperand(0).setMBB(NewDest);
MI->getOperand(1).setImm(CC);
@@ -1273,9 +1327,9 @@ ARMConstantIslands::FixUpConditionalBr(MachineFunction &Fn, ImmBranch &Br) {
}
MachineBasicBlock *NextBB = next(MachineFunction::iterator(MBB));
- DOUT << " Insert B to BB#" << DestBB->getNumber()
- << " also invert condition and change dest. to BB#"
- << NextBB->getNumber() << "\n";
+ DEBUG(errs() << " Insert B to BB#" << DestBB->getNumber()
+ << " also invert condition and change dest. to BB#"
+ << NextBB->getNumber() << "\n");
// Insert a new conditional branch and a new unconditional branch.
// Also update the ImmBranch as well as adding a new entry for the new branch.
@@ -1300,14 +1354,17 @@ ARMConstantIslands::FixUpConditionalBr(MachineFunction &Fn, ImmBranch &Br) {
}
/// UndoLRSpillRestore - Remove Thumb push / pop instructions that only spills
-/// LR / restores LR to pc.
+/// LR / restores LR to pc. FIXME: This is done here because it's only possible
+/// to do this if tBfar is not used.
bool ARMConstantIslands::UndoLRSpillRestore() {
bool MadeChange = false;
for (unsigned i = 0, e = PushPopMIs.size(); i != e; ++i) {
MachineInstr *MI = PushPopMIs[i];
+ // First two operands are predicates, the third is a zero since there
+ // is no writeback.
if (MI->getOpcode() == ARM::tPOP_RET &&
- MI->getOperand(0).getReg() == ARM::PC &&
- MI->getNumExplicitOperands() == 1) {
+ MI->getOperand(3).getReg() == ARM::PC &&
+ MI->getNumExplicitOperands() == 4) {
BuildMI(MI->getParent(), MI->getDebugLoc(), TII->get(ARM::tBX_RET));
MI->eraseFromParent();
MadeChange = true;
@@ -1315,3 +1372,201 @@ bool ARMConstantIslands::UndoLRSpillRestore() {
}
return MadeChange;
}
+
+bool ARMConstantIslands::OptimizeThumb2Instructions(MachineFunction &MF) {
+ bool MadeChange = false;
+
+ // Shrink ADR and LDR from constantpool.
+ for (unsigned i = 0, e = CPUsers.size(); i != e; ++i) {
+ CPUser &U = CPUsers[i];
+ unsigned Opcode = U.MI->getOpcode();
+ unsigned NewOpc = 0;
+ unsigned Scale = 1;
+ unsigned Bits = 0;
+ switch (Opcode) {
+ default: break;
+ case ARM::t2LEApcrel:
+ if (isARMLowRegister(U.MI->getOperand(0).getReg())) {
+ NewOpc = ARM::tLEApcrel;
+ Bits = 8;
+ Scale = 4;
+ }
+ break;
+ case ARM::t2LDRpci:
+ if (isARMLowRegister(U.MI->getOperand(0).getReg())) {
+ NewOpc = ARM::tLDRpci;
+ Bits = 8;
+ Scale = 4;
+ }
+ break;
+ }
+
+ if (!NewOpc)
+ continue;
+
+ unsigned UserOffset = GetOffsetOf(U.MI) + 4;
+ unsigned MaxOffs = ((1 << Bits) - 1) * Scale;
+ // FIXME: Check if offset is multiple of scale if scale is not 4.
+ if (CPEIsInRange(U.MI, UserOffset, U.CPEMI, MaxOffs, false, true)) {
+ U.MI->setDesc(TII->get(NewOpc));
+ MachineBasicBlock *MBB = U.MI->getParent();
+ BBSizes[MBB->getNumber()] -= 2;
+ AdjustBBOffsetsAfter(MBB, -2);
+ ++NumT2CPShrunk;
+ MadeChange = true;
+ }
+ }
+
+ MadeChange |= OptimizeThumb2Branches(MF);
+ MadeChange |= OptimizeThumb2JumpTables(MF);
+ return MadeChange;
+}
+
+bool ARMConstantIslands::OptimizeThumb2Branches(MachineFunction &MF) {
+ bool MadeChange = false;
+
+ for (unsigned i = 0, e = ImmBranches.size(); i != e; ++i) {
+ ImmBranch &Br = ImmBranches[i];
+ unsigned Opcode = Br.MI->getOpcode();
+ unsigned NewOpc = 0;
+ unsigned Scale = 1;
+ unsigned Bits = 0;
+ switch (Opcode) {
+ default: break;
+ case ARM::t2B:
+ NewOpc = ARM::tB;
+ Bits = 11;
+ Scale = 2;
+ break;
+ case ARM::t2Bcc:
+ NewOpc = ARM::tBcc;
+ Bits = 8;
+ Scale = 2;
+ break;
+ }
+ if (!NewOpc)
+ continue;
+
+ unsigned MaxOffs = ((1 << (Bits-1))-1) * Scale;
+ MachineBasicBlock *DestBB = Br.MI->getOperand(0).getMBB();
+ if (BBIsInRange(Br.MI, DestBB, MaxOffs)) {
+ Br.MI->setDesc(TII->get(NewOpc));
+ MachineBasicBlock *MBB = Br.MI->getParent();
+ BBSizes[MBB->getNumber()] -= 2;
+ AdjustBBOffsetsAfter(MBB, -2);
+ ++NumT2BrShrunk;
+ MadeChange = true;
+ }
+ }
+
+ return MadeChange;
+}
+
+
+/// OptimizeThumb2JumpTables - Use tbb / tbh instructions to generate smaller
+/// jumptables when it's possible.
+bool ARMConstantIslands::OptimizeThumb2JumpTables(MachineFunction &MF) {
+ bool MadeChange = false;
+
+ // FIXME: After the tables are shrunk, can we get rid some of the
+ // constantpool tables?
+ const MachineJumpTableInfo *MJTI = MF.getJumpTableInfo();
+ const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
+ for (unsigned i = 0, e = T2JumpTables.size(); i != e; ++i) {
+ MachineInstr *MI = T2JumpTables[i];
+ const TargetInstrDesc &TID = MI->getDesc();
+ unsigned NumOps = TID.getNumOperands();
+ unsigned JTOpIdx = NumOps - (TID.isPredicable() ? 3 : 2);
+ MachineOperand JTOP = MI->getOperand(JTOpIdx);
+ unsigned JTI = JTOP.getIndex();
+ assert(JTI < JT.size());
+
+ bool ByteOk = true;
+ bool HalfWordOk = true;
+ unsigned JTOffset = GetOffsetOf(MI) + 4;
+ const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
+ for (unsigned j = 0, ee = JTBBs.size(); j != ee; ++j) {
+ MachineBasicBlock *MBB = JTBBs[j];
+ unsigned DstOffset = BBOffsets[MBB->getNumber()];
+ // Negative offset is not ok. FIXME: We should change BB layout to make
+ // sure all the branches are forward.
+ if (ByteOk && (DstOffset - JTOffset) > ((1<<8)-1)*2)
+ ByteOk = false;
+ unsigned TBHLimit = ((1<<16)-1)*2;
+ if (HalfWordOk && (DstOffset - JTOffset) > TBHLimit)
+ HalfWordOk = false;
+ if (!ByteOk && !HalfWordOk)
+ break;
+ }
+
+ if (ByteOk || HalfWordOk) {
+ MachineBasicBlock *MBB = MI->getParent();
+ unsigned BaseReg = MI->getOperand(0).getReg();
+ bool BaseRegKill = MI->getOperand(0).isKill();
+ if (!BaseRegKill)
+ continue;
+ unsigned IdxReg = MI->getOperand(1).getReg();
+ bool IdxRegKill = MI->getOperand(1).isKill();
+ MachineBasicBlock::iterator PrevI = MI;
+ if (PrevI == MBB->begin())
+ continue;
+
+ MachineInstr *AddrMI = --PrevI;
+ bool OptOk = true;
+ // Examine the instruction that calculate the jumptable entry address.
+ // If it's not the one just before the t2BR_JT, we won't delete it, then
+ // it's not worth doing the optimization.
+ for (unsigned k = 0, eee = AddrMI->getNumOperands(); k != eee; ++k) {
+ const MachineOperand &MO = AddrMI->getOperand(k);
+ if (!MO.isReg() || !MO.getReg())
+ continue;
+ if (MO.isDef() && MO.getReg() != BaseReg) {
+ OptOk = false;
+ break;
+ }
+ if (MO.isUse() && !MO.isKill() && MO.getReg() != IdxReg) {
+ OptOk = false;
+ break;
+ }
+ }
+ if (!OptOk)
+ continue;
+
+ // The previous instruction should be a tLEApcrel or t2LEApcrelJT, we want
+ // to delete it as well.
+ MachineInstr *LeaMI = --PrevI;
+ if ((LeaMI->getOpcode() != ARM::tLEApcrelJT &&
+ LeaMI->getOpcode() != ARM::t2LEApcrelJT) ||
+ LeaMI->getOperand(0).getReg() != BaseReg)
+ OptOk = false;
+
+ if (!OptOk)
+ continue;
+
+ unsigned Opc = ByteOk ? ARM::t2TBB : ARM::t2TBH;
+ MachineInstr *NewJTMI = BuildMI(MBB, MI->getDebugLoc(), TII->get(Opc))
+ .addReg(IdxReg, getKillRegState(IdxRegKill))
+ .addJumpTableIndex(JTI, JTOP.getTargetFlags())
+ .addImm(MI->getOperand(JTOpIdx+1).getImm());
+ // FIXME: Insert an "ALIGN" instruction to ensure the next instruction
+ // is 2-byte aligned. For now, asm printer will fix it up.
+ unsigned NewSize = TII->GetInstSizeInBytes(NewJTMI);
+ unsigned OrigSize = TII->GetInstSizeInBytes(AddrMI);
+ OrigSize += TII->GetInstSizeInBytes(LeaMI);
+ OrigSize += TII->GetInstSizeInBytes(MI);
+
+ AddrMI->eraseFromParent();
+ LeaMI->eraseFromParent();
+ MI->eraseFromParent();
+
+ int delta = OrigSize - NewSize;
+ BBSizes[MBB->getNumber()] -= delta;
+ AdjustBBOffsetsAfter(MBB, -delta);
+
+ ++NumTBs;
+ MadeChange = true;
+ }
+ }
+
+ return MadeChange;
+}
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