[llvm] r194026 - Revert r194019 to r194021, "Submit the basic port of the rest of ARM constant islands code to Mips."
NAKAMURA Takumi
geek4civic at gmail.com
Mon Nov 4 15:14:36 PST 2013
Author: chapuni
Date: Mon Nov 4 17:14:36 2013
New Revision: 194026
URL: http://llvm.org/viewvc/llvm-project?rev=194026&view=rev
Log:
Revert r194019 to r194021, "Submit the basic port of the rest of ARM constant islands code to Mips."
It broke -Asserts build.
Removed:
llvm/trunk/test/CodeGen/Mips/const4.ll
Modified:
llvm/trunk/lib/Target/Mips/Mips16InstrInfo.td
llvm/trunk/lib/Target/Mips/MipsConstantIslandPass.cpp
Modified: llvm/trunk/lib/Target/Mips/Mips16InstrInfo.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/Mips16InstrInfo.td?rev=194026&r1=194025&r2=194026&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/Mips16InstrInfo.td (original)
+++ llvm/trunk/lib/Target/Mips/Mips16InstrInfo.td Mon Nov 4 17:14:36 2013
@@ -60,11 +60,6 @@ class FRI16_ins<bits<5> op, string asmst
InstrItinClass itin>:
FRI16_ins_base<op, asmstr, "\t$rx, $imm \t# 16 bit inst", itin>;
-class FRI16_TCP_ins<bits<5> _op, string asmstr,
- InstrItinClass itin>:
- FRI16<_op, (outs CPU16Regs:$rx), (ins pcrel16:$imm, i32imm:$size),
- !strconcat(asmstr, "\t$rx, $imm\t# 16 bit inst"), [], itin>;
-
class FRI16R_ins_base<bits<5> op, string asmstr, string asmstr2,
InstrItinClass itin>:
FRI16<op, (outs), (ins CPU16Regs:$rx, simm16:$imm),
@@ -179,7 +174,7 @@ class FEXT_RI16_B_ins<bits<5> _op, strin
class FEXT_RI16_TCP_ins<bits<5> _op, string asmstr,
InstrItinClass itin>:
- FEXT_RI16<_op, (outs CPU16Regs:$rx), (ins pcrel16:$imm, i32imm:$size),
+ FEXT_RI16<_op, (outs CPU16Regs:$rx), (ins pcrel16:$imm),
!strconcat(asmstr, "\t$rx, $imm"), [], itin>;
class FEXT_2RI16_ins<bits<5> _op, string asmstr,
@@ -807,8 +802,6 @@ def LwRxSpImmX16: FEXT_RI16_SP_explicit_
let Uses = [SP];
}
-def LwRxPcTcp16: FRI16_TCP_ins<0b10110, "lw", IILoad>, MayLoad;
-
def LwRxPcTcpX16: FEXT_RI16_TCP_ins<0b10110, "lw", IILoad>, MayLoad;
//
// Format: MOVE r32, rz MIPS16e
@@ -1876,4 +1869,3 @@ let neverHasSideEffects = 1, isNotDuplic
def CONSTPOOL_ENTRY :
MipsPseudo16<(outs), (ins cpinst_operand:$instid, cpinst_operand:$cpidx,
i32imm:$size), "foo", []>;
-
Modified: llvm/trunk/lib/Target/Mips/MipsConstantIslandPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/MipsConstantIslandPass.cpp?rev=194026&r1=194025&r2=194026&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/MipsConstantIslandPass.cpp (original)
+++ llvm/trunk/lib/Target/Mips/MipsConstantIslandPass.cpp Mon Nov 4 17:14:36 2013
@@ -27,7 +27,6 @@
#include "Mips.h"
#include "MCTargetDesc/MipsBaseInfo.h"
-#include "MipsMachineFunction.h"
#include "MipsTargetMachine.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
@@ -43,197 +42,30 @@
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
-#include "llvm/Support/Format.h"
#include <algorithm>
using namespace llvm;
STATISTIC(NumCPEs, "Number of constpool entries");
-STATISTIC(NumSplit, "Number of uncond branches inserted");
-#ifdef IN_PROGRESS
-STATISTIC(NumCBrFixed, "Number of cond branches fixed");
-#endif
-STATISTIC(NumUBrFixed, "Number of uncond branches fixed");
// FIXME: This option should be removed once it has received sufficient testing.
static cl::opt<bool>
AlignConstantIslands("mips-align-constant-islands", cl::Hidden, cl::init(true),
cl::desc("Align constant islands in code"));
-
-// Rather than do make check tests with huge amounts of code, we force
-// the test to use this amount.
-//
-static cl::opt<int> ConstantIslandsSmallOffset(
- "mips-constant-islands-small-offset",
- cl::init(0),
- cl::desc("Make small offsets be this amount for testing purposes"),
- cl::Hidden);
-
-/// UnknownPadding - Return the worst case padding that could result from
-/// unknown offset bits. This does not include alignment padding caused by
-/// known offset bits.
-///
-/// @param LogAlign log2(alignment)
-/// @param KnownBits Number of known low offset bits.
-static inline unsigned UnknownPadding(unsigned LogAlign, unsigned KnownBits) {
- if (KnownBits < LogAlign)
- return (1u << LogAlign) - (1u << KnownBits);
- return 0;
-}
-
namespace {
-
-
typedef MachineBasicBlock::iterator Iter;
typedef MachineBasicBlock::reverse_iterator ReverseIter;
- /// MipsConstantIslands - Due to limited PC-relative displacements, Mips
- /// requires constant pool entries to be scattered among the instructions
- /// inside a function. To do this, it completely ignores the normal LLVM
- /// constant pool; instead, it places constants wherever it feels like with
- /// special instructions.
- ///
- /// The terminology used in this pass includes:
- /// Islands - Clumps of constants placed in the function.
- /// Water - Potential places where an island could be formed.
- /// CPE - A constant pool entry that has been placed somewhere, which
- /// tracks a list of users.
-
class MipsConstantIslands : public MachineFunctionPass {
- /// BasicBlockInfo - Information about the offset and size of a single
- /// basic block.
- struct BasicBlockInfo {
- /// Offset - Distance from the beginning of the function to the beginning
- /// of this basic block.
- ///
- /// Offsets are computed assuming worst case padding before an aligned
- /// block. This means that subtracting basic block offsets always gives a
- /// conservative estimate of the real distance which may be smaller.
- ///
- /// Because worst case padding is used, the computed offset of an aligned
- /// block may not actually be aligned.
- unsigned Offset;
-
- /// Size - Size of the basic block in bytes. If the block contains
- /// inline assembly, this is a worst case estimate.
- ///
- /// The size does not include any alignment padding whether from the
- /// beginning of the block, or from an aligned jump table at the end.
- unsigned Size;
-
- /// KnownBits - The number of low bits in Offset that are known to be
- /// exact. The remaining bits of Offset are an upper bound.
- uint8_t KnownBits;
-
- /// Unalign - When non-zero, the block contains instructions (inline asm)
- /// of unknown size. The real size may be smaller than Size bytes by a
- /// multiple of 1 << Unalign.
- uint8_t Unalign;
-
- /// PostAlign - When non-zero, the block terminator contains a .align
- /// directive, so the end of the block is aligned to 1 << PostAlign
- /// bytes.
- uint8_t PostAlign;
-
- BasicBlockInfo() : Offset(0), Size(0), KnownBits(0), Unalign(0),
- PostAlign(0) {}
-
- /// Compute the number of known offset bits internally to this block.
- /// This number should be used to predict worst case padding when
- /// splitting the block.
- unsigned internalKnownBits() const {
- unsigned Bits = Unalign ? Unalign : KnownBits;
- // If the block size isn't a multiple of the known bits, assume the
- // worst case padding.
- if (Size & ((1u << Bits) - 1))
- Bits = countTrailingZeros(Size);
- return Bits;
- }
-
- /// Compute the offset immediately following this block. If LogAlign is
- /// specified, return the offset the successor block will get if it has
- /// this alignment.
- unsigned postOffset(unsigned LogAlign = 0) const {
- unsigned PO = Offset + Size;
- return PO;
- }
-
- /// Compute the number of known low bits of postOffset. If this block
- /// contains inline asm, the number of known bits drops to the
- /// instruction alignment. An aligned terminator may increase the number
- /// of know bits.
- /// If LogAlign is given, also consider the alignment of the next block.
- unsigned postKnownBits(unsigned LogAlign = 0) const {
- return std::max(std::max(unsigned(PostAlign), LogAlign),
- internalKnownBits());
- }
- };
-
- std::vector<BasicBlockInfo> BBInfo;
-
- /// WaterList - A sorted list of basic blocks where islands could be placed
- /// (i.e. blocks that don't fall through to the following block, due
- /// to a return, unreachable, or unconditional branch).
- std::vector<MachineBasicBlock*> WaterList;
-
- /// NewWaterList - The subset of WaterList that was created since the
- /// previous iteration by inserting unconditional branches.
- SmallSet<MachineBasicBlock*, 4> NewWaterList;
-
- 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. The HighWaterMark records the
- /// highest basic block where a new CPEntry can be placed. To ensure this
- /// pass terminates, the CP entries are initially placed at the end of the
- /// function and then move monotonically to lower addresses. The
- /// exception to this rule is when the current CP entry for a particular
- /// CPUser is out of range, but there is another CP entry for the same
- /// constant value in range. We want to use the existing in-range CP
- /// entry, but if it later moves out of range, the search for new water
- /// should resume where it left off. The HighWaterMark is used to record
- /// that point.
- struct CPUser {
- MachineInstr *MI;
- MachineInstr *CPEMI;
- MachineBasicBlock *HighWaterMark;
- private:
- unsigned MaxDisp;
- unsigned LongFormMaxDisp; // mips16 has 16/32 bit instructions
- // with different displacements
- unsigned LongFormOpcode;
- public:
- bool NegOk;
- bool IsSoImm;
- bool KnownAlignment;
- CPUser(MachineInstr *mi, MachineInstr *cpemi, unsigned maxdisp,
- bool neg, bool soimm, unsigned longformmaxdisp, unsigned longformopcode)
- : MI(mi), CPEMI(cpemi), MaxDisp(maxdisp),
- LongFormMaxDisp(longformmaxdisp), LongFormOpcode(longformopcode),
- NegOk(neg), IsSoImm(soimm), KnownAlignment(false) {
- HighWaterMark = CPEMI->getParent();
- }
- /// getMaxDisp - Returns the maximum displacement supported by MI.
- /// Correct for unknown alignment.
- /// Conservatively subtract 2 bytes to handle weird alignment effects.
- unsigned getMaxDisp() const {
- unsigned xMaxDisp = ConstantIslandsSmallOffset? ConstantIslandsSmallOffset: MaxDisp;
- return (KnownAlignment ? xMaxDisp : xMaxDisp - 2) - 2;
- }
- unsigned getLongFormMaxDisp() const {
- return (KnownAlignment ? LongFormMaxDisp : LongFormMaxDisp - 2) - 2;
- }
- unsigned getLongFormOpcode() const {
- return LongFormOpcode;
- }
- };
-
- /// CPUsers - Keep track of all of the machine instructions that use various
- /// constant pools and their max displacement.
- std::vector<CPUser> CPUsers;
+ const TargetMachine &TM;
+ bool IsPIC;
+ unsigned ABI;
+ const MipsSubtarget *STI;
+ const MipsInstrInfo *TII;
+ MachineFunction *MF;
+ MachineConstantPool *MCP;
/// CPEntry - One per constant pool entry, keeping the machine instruction
/// pointer, the constpool index, and the number of CPUser's which
@@ -253,55 +85,13 @@ namespace {
/// put in the vector of the original element, but have distinct CPIs.
std::vector<std::vector<CPEntry> > CPEntries;
- /// ImmBranch - One per immediate branch, keeping the machine instruction
- /// pointer, conditional or unconditional, the max displacement,
- /// and (if isCond is true) the corresponding unconditional branch
- /// opcode.
- struct ImmBranch {
- MachineInstr *MI;
- unsigned MaxDisp : 31;
- bool isCond : 1;
- int UncondBr;
- ImmBranch(MachineInstr *mi, unsigned maxdisp, bool cond, int ubr)
- : MI(mi), MaxDisp(maxdisp), isCond(cond), UncondBr(ubr) {}
- };
-
- /// ImmBranches - Keep track of all the immediate branch instructions.
- ///
- std::vector<ImmBranch> ImmBranches;
-
- /// HasFarJump - True if any far jump instruction has been emitted during
- /// the branch fix up pass.
- bool HasFarJump;
-
- const TargetMachine &TM;
- bool IsPIC;
- unsigned ABI;
- const MipsSubtarget *STI;
- const MipsInstrInfo *TII;
- MipsFunctionInfo *MFI;
- MachineFunction *MF;
- MachineConstantPool *MCP;
-
- unsigned PICLabelUId;
- bool PrescannedForConstants;
-
- void initPICLabelUId(unsigned UId) {
- PICLabelUId = UId;
- }
-
-
- unsigned createPICLabelUId() {
- return PICLabelUId++;
- }
-
public:
static char ID;
MipsConstantIslands(TargetMachine &tm)
: MachineFunctionPass(ID), TM(tm),
IsPIC(TM.getRelocationModel() == Reloc::PIC_),
ABI(TM.getSubtarget<MipsSubtarget>().getTargetABI()),
- STI(&TM.getSubtarget<MipsSubtarget>()), MF(0), MCP(0), PrescannedForConstants(false){}
+ STI(&TM.getSubtarget<MipsSubtarget>()), MF(0), MCP(0){}
virtual const char *getPassName() const {
return "Mips Constant Islands";
@@ -310,49 +100,6 @@ namespace {
bool runOnMachineFunction(MachineFunction &F);
void doInitialPlacement(std::vector<MachineInstr*> &CPEMIs);
- CPEntry *findConstPoolEntry(unsigned CPI, const MachineInstr *CPEMI);
- unsigned getCPELogAlign(const MachineInstr *CPEMI);
- void initializeFunctionInfo(const std::vector<MachineInstr*> &CPEMIs);
- unsigned getOffsetOf(MachineInstr *MI) const;
- unsigned getUserOffset(CPUser&) const;
- void dumpBBs();
- void verify();
-
- bool isOffsetInRange(unsigned UserOffset, unsigned TrialOffset,
- unsigned Disp, bool NegativeOK, bool IsSoImm = false);
- bool isOffsetInRange(unsigned UserOffset, unsigned TrialOffset,
- const CPUser &U) {
- return isOffsetInRange(UserOffset, TrialOffset,
- U.getMaxDisp(), U.NegOk, U.IsSoImm);
- }
- bool isLongFormOffsetInRange(unsigned UserOffset, unsigned TrialOffset,
- const CPUser &U) {
- return isOffsetInRange(UserOffset, TrialOffset,
- U.getLongFormMaxDisp(), U.NegOk, U.IsSoImm);
- }
- void computeBlockSize(MachineBasicBlock *MBB);
- MachineBasicBlock *splitBlockBeforeInstr(MachineInstr *MI);
- void updateForInsertedWaterBlock(MachineBasicBlock *NewBB);
- void adjustBBOffsetsAfter(MachineBasicBlock *BB);
- bool decrementCPEReferenceCount(unsigned CPI, MachineInstr* CPEMI);
- int findInRangeCPEntry(CPUser& U, unsigned UserOffset);
- int findLongFormInRangeCPEntry(CPUser& U, unsigned UserOffset);
- bool findAvailableWater(CPUser&U, unsigned UserOffset,
- water_iterator &WaterIter);
- void createNewWater(unsigned CPUserIndex, unsigned UserOffset,
- MachineBasicBlock *&NewMBB);
- bool handleConstantPoolUser(unsigned CPUserIndex);
- void removeDeadCPEMI(MachineInstr *CPEMI);
- bool removeUnusedCPEntries();
- bool isCPEntryInRange(MachineInstr *MI, unsigned UserOffset,
- MachineInstr *CPEMI, unsigned Disp, bool NegOk,
- bool DoDump = false);
- bool isWaterInRange(unsigned UserOffset, MachineBasicBlock *Water,
- CPUser &U, unsigned &Growth);
- bool isBBInRange(MachineInstr *MI, MachineBasicBlock *BB, unsigned Disp);
- bool fixupImmediateBr(ImmBranch &Br);
- bool fixupConditionalBr(ImmBranch &Br);
- bool fixupUnconditionalBr(ImmBranch &Br);
void prescanForConstants();
@@ -363,19 +110,6 @@ namespace {
char MipsConstantIslands::ID = 0;
} // end of anonymous namespace
-/// print block size and offset information - debugging
-void MipsConstantIslands::dumpBBs() {
- DEBUG({
- for (unsigned J = 0, E = BBInfo.size(); J !=E; ++J) {
- const BasicBlockInfo &BBI = BBInfo[J];
- dbgs() << format("%08x BB#%u\t", BBI.Offset, J)
- << " kb=" << unsigned(BBI.KnownBits)
- << " ua=" << unsigned(BBI.Unalign)
- << " pa=" << unsigned(BBI.PostAlign)
- << format(" size=%#x\n", BBInfo[J].Size);
- }
- });
-}
/// createMipsLongBranchPass - Returns a pass that converts branches to long
/// branches.
FunctionPass *llvm::createMipsConstantIslandPass(MipsTargetMachine &tm) {
@@ -393,15 +127,13 @@ bool MipsConstantIslands::runOnMachineFu
return false;
}
TII = (const MipsInstrInfo*)MF->getTarget().getInstrInfo();
- MFI = MF->getInfo<MipsFunctionInfo>();
DEBUG(dbgs() << "constant island processing " << "\n");
//
// will need to make predermination if there is any constants we need to
// put in constant islands. TBD.
//
- if (!PrescannedForConstants) prescanForConstants();
+ prescanForConstants();
- HasFarJump = false;
// This pass invalidates liveness information when it splits basic blocks.
MF->getRegInfo().invalidateLiveness();
@@ -409,66 +141,13 @@ bool MipsConstantIslands::runOnMachineFu
// the numbers agree with the position of the block in the function.
MF->RenumberBlocks();
- bool MadeChange = false;
-
// 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(CPEMIs);
- /// The next UID to take is the first unused one.
- initPICLabelUId(CPEMIs.size());
-
- // 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.
- initializeFunctionInfo(CPEMIs);
- CPEMIs.clear();
- DEBUG(dumpBBs());
-
- /// Remove dead constant pool entries.
- MadeChange |= removeUnusedCPEntries();
-
- // Iteratively place constant pool entries and fix up branches until there
- // is no change.
- unsigned NoCPIters = 0, NoBRIters = 0;
- (void)NoBRIters;
- while (true) {
- DEBUG(dbgs() << "Beginning CP iteration #" << NoCPIters << '\n');
- bool CPChange = false;
- for (unsigned i = 0, e = CPUsers.size(); i != e; ++i)
- CPChange |= handleConstantPoolUser(i);
- if (CPChange && ++NoCPIters > 30)
- report_fatal_error("Constant Island pass failed to converge!");
- DEBUG(dumpBBs());
-
- // Clear NewWaterList now. If we split a block for branches, it should
- // appear as "new water" for the next iteration of constant pool placement.
- NewWaterList.clear();
-
- DEBUG(dbgs() << "Beginning BR iteration #" << NoBRIters << '\n');
- bool BRChange = false;
-#ifdef IN_PROGRESS
- for (unsigned i = 0, e = ImmBranches.size(); i != e; ++i)
- BRChange |= fixupImmediateBr(ImmBranches[i]);
- if (BRChange && ++NoBRIters > 30)
- report_fatal_error("Branch Fix Up pass failed to converge!");
- DEBUG(dumpBBs());
-#endif
- if (!CPChange && !BRChange)
- break;
- MadeChange = true;
- }
-
- DEBUG(dbgs() << '\n'; dumpBBs());
-
- BBInfo.clear();
- WaterList.clear();
- CPUsers.clear();
- CPEntries.clear();
- ImmBranches.clear();
- return MadeChange;
+ return true;
}
/// doInitialPlacement - Perform the initial placement of the constant pool
@@ -537,1165 +216,9 @@ MipsConstantIslands::doInitialPlacement(
DEBUG(BB->dump());
}
-/// BBHasFallthrough - Return true if the specified basic block can fallthrough
-/// into the block immediately after it.
-static bool BBHasFallthrough(MachineBasicBlock *MBB) {
- // Get the next machine basic block in the function.
- MachineFunction::iterator MBBI = MBB;
- // Can't fall off end of function.
- if (llvm::next(MBBI) == MBB->getParent()->end())
- return false;
-
- MachineBasicBlock *NextBB = llvm::next(MBBI);
- for (MachineBasicBlock::succ_iterator I = MBB->succ_begin(),
- E = MBB->succ_end(); I != E; ++I)
- if (*I == NextBB)
- return true;
-
- return false;
-}
-
-/// findConstPoolEntry - Given the constpool index and CONSTPOOL_ENTRY MI,
-/// look up the corresponding CPEntry.
-MipsConstantIslands::CPEntry
-*MipsConstantIslands::findConstPoolEntry(unsigned CPI,
- const MachineInstr *CPEMI) {
- std::vector<CPEntry> &CPEs = CPEntries[CPI];
- // Number of entries per constpool index should be small, just do a
- // linear search.
- for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
- if (CPEs[i].CPEMI == CPEMI)
- return &CPEs[i];
- }
- return NULL;
-}
-
-/// getCPELogAlign - Returns the required alignment of the constant pool entry
-/// represented by CPEMI. Alignment is measured in log2(bytes) units.
-unsigned MipsConstantIslands::getCPELogAlign(const MachineInstr *CPEMI) {
- assert(CPEMI && CPEMI->getOpcode() == Mips::CONSTPOOL_ENTRY);
-
- // Everything is 4-byte aligned unless AlignConstantIslands is set.
- if (!AlignConstantIslands)
- return 2;
-
- unsigned CPI = CPEMI->getOperand(1).getIndex();
- assert(CPI < MCP->getConstants().size() && "Invalid constant pool index.");
- unsigned Align = MCP->getConstants()[CPI].getAlignment();
- assert(isPowerOf2_32(Align) && "Invalid CPE alignment");
- return Log2_32(Align);
-}
-
-/// initializeFunctionInfo - 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 MipsConstantIslands::
-initializeFunctionInfo(const std::vector<MachineInstr*> &CPEMIs) {
- BBInfo.clear();
- BBInfo.resize(MF->getNumBlockIDs());
-
- // First thing, compute the size of all basic blocks, and see if the function
- // has any inline assembly in it. If so, we have to be conservative about
- // alignment assumptions, as we don't know for sure the size of any
- // instructions in the inline assembly.
- for (MachineFunction::iterator I = MF->begin(), E = MF->end(); I != E; ++I)
- computeBlockSize(I);
-
- // The known bits of the entry block offset are determined by the function
- // alignment.
- BBInfo.front().KnownBits = MF->getAlignment();
-
- // Compute block offsets.
- adjustBBOffsetsAfter(MF->begin());
-
- // Now go back through the instructions and build up our data structures.
- for (MachineFunction::iterator MBBI = MF->begin(), E = MF->end();
- MBBI != E; ++MBBI) {
- MachineBasicBlock &MBB = *MBBI;
-
- // If this block doesn't fall through into the next MBB, then this is
- // 'water' that a constant pool island could be placed.
- if (!BBHasFallthrough(&MBB))
- WaterList.push_back(&MBB);
- for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end();
- I != E; ++I) {
- if (I->isDebugValue())
- continue;
-
- int Opc = I->getOpcode();
- if (I->isBranch()) {
- bool isCond = false;
- unsigned Bits = 0;
- unsigned Scale = 1;
- int UOpc = Opc;
-
- switch (Opc) {
- default:
- continue; // Ignore other JT branches
-#ifdef IN_PROGRESS
- case ARM::t2BR_JT:
- T2JumpTables.push_back(I);
- continue; // Does not get an entry in ImmBranches
- case ARM::Bcc:
- isCond = true;
- UOpc = ARM::B;
- // Fallthrough
- case ARM::B:
- Bits = 24;
- Scale = 4;
- break;
- case ARM::tBcc:
- isCond = true;
- UOpc = ARM::tB;
- Bits = 8;
- Scale = 2;
- break;
- case ARM::tB:
- Bits = 11;
- Scale = 2;
- break;
- case ARM::t2Bcc:
- isCond = true;
- UOpc = ARM::t2B;
- Bits = 20;
- Scale = 2;
- break;
- case ARM::t2B:
- Bits = 24;
- Scale = 2;
- break;
-#endif
- }
- // Record this immediate branch.
- unsigned MaxOffs = ((1 << (Bits-1))-1) * Scale;
- ImmBranches.push_back(ImmBranch(I, MaxOffs, isCond, UOpc));
-
- }
-
-
- if (Opc == Mips::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()) {
-
- // We found one. The addressing mode tells us the max displacement
- // from the PC that this instruction permits.
-
- // Basic size info comes from the TSFlags field.
- unsigned Bits = 0;
- unsigned Scale = 1;
- bool NegOk = false;
- bool IsSoImm = false;
- unsigned LongFormBits = 0;
- unsigned LongFormScale = 0;
- unsigned LongFormOpcode = 0;
- switch (Opc) {
- default:
- llvm_unreachable("Unknown addressing mode for CP reference!");
- case Mips::LwRxPcTcp16:
- Bits = 8;
- Scale = 2;
- LongFormOpcode = Mips::LwRxPcTcpX16;
- break;
- case Mips::LwRxPcTcpX16:
- Bits = 16;
- Scale = 2;
- break;
-#ifdef IN_PROGRESS
- // 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'll check for other
- // displacements that fits in a SoImm as well.
- Bits = 8;
- Scale = 4;
- NegOk = true;
- IsSoImm = true;
- break;
- case ARM::t2LEApcrel:
- Bits = 12;
- NegOk = true;
- break;
- case ARM::tLEApcrel:
- Bits = 8;
- Scale = 4;
- break;
-
- case ARM::LDRBi12:
- case ARM::LDRi12:
- case ARM::LDRcp:
- case ARM::t2LDRpci:
- Bits = 12; // +-offset_12
- NegOk = true;
- break;
-
- case ARM::tLDRpci:
- Bits = 8;
- Scale = 4; // +(offset_8*4)
- break;
-
- case ARM::VLDRD:
- case ARM::VLDRS:
- Bits = 8;
- Scale = 4; // +-(offset_8*4)
- NegOk = true;
- break;
-#endif
- }
- // Remember that this is a user of a CP entry.
- unsigned CPI = I->getOperand(op).getIndex();
- MachineInstr *CPEMI = CPEMIs[CPI];
- unsigned MaxOffs = ((1 << Bits)-1) * Scale;
- unsigned LongFormMaxOffs = ((1 << LongFormBits)-1) * LongFormScale;
- CPUsers.push_back(CPUser(I, CPEMI, MaxOffs, NegOk, IsSoImm, LongFormMaxOffs,
- LongFormOpcode));
-
- // Increment corresponding CPEntry reference count.
- CPEntry *CPE = findConstPoolEntry(CPI, CPEMI);
- assert(CPE && "Cannot find a corresponding CPEntry!");
- CPE->RefCount++;
-
- // Instructions can only use one CP entry, don't bother scanning the
- // rest of the operands.
- break;
-
- }
-
- }
- }
-
-}
-
-/// computeBlockSize - Compute the size and some alignment information for MBB.
-/// This function updates BBInfo directly.
-void MipsConstantIslands::computeBlockSize(MachineBasicBlock *MBB) {
- BasicBlockInfo &BBI = BBInfo[MBB->getNumber()];
- BBI.Size = 0;
- BBI.Unalign = 0;
- BBI.PostAlign = 0;
-
- for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end(); I != E;
- ++I)
- BBI.Size += TII->GetInstSizeInBytes(I);
-
-}
-
-/// getOffsetOf - Return the current offset of the specified machine instruction
-/// from the start of the function. This offset changes as stuff is moved
-/// around inside the function.
-unsigned MipsConstantIslands::getOffsetOf(MachineInstr *MI) const {
- MachineBasicBlock *MBB = MI->getParent();
-
- // The offset is composed of two things: the sum of the sizes of all MBB's
- // before this instruction's block, and the offset from the start of the block
- // it is in.
- unsigned Offset = BBInfo[MBB->getNumber()].Offset;
-
- // Sum instructions before MI in MBB.
- for (MachineBasicBlock::iterator I = MBB->begin(); &*I != MI; ++I) {
- assert(I != MBB->end() && "Didn't find MI in its own basic block?");
- Offset += TII->GetInstSizeInBytes(I);
- }
- return Offset;
-}
-
-/// CompareMBBNumbers - Little predicate function to sort the WaterList by MBB
-/// ID.
-static bool CompareMBBNumbers(const MachineBasicBlock *LHS,
- const MachineBasicBlock *RHS) {
- return LHS->getNumber() < RHS->getNumber();
-}
-
-/// updateForInsertedWaterBlock - When a block is newly inserted into the
-/// machine function, it upsets all of the block numbers. Renumber the blocks
-/// and update the arrays that parallel this numbering.
-void MipsConstantIslands::updateForInsertedWaterBlock(MachineBasicBlock *NewBB) {
- // Renumber the MBB's to keep them consecutive.
- NewBB->getParent()->RenumberBlocks(NewBB);
-
- // Insert an entry into BBInfo to align it properly with the (newly
- // renumbered) block numbers.
- BBInfo.insert(BBInfo.begin() + NewBB->getNumber(), BasicBlockInfo());
-
- // Next, update WaterList. Specifically, we need to add NewMBB as having
- // available water after it.
- water_iterator IP =
- std::lower_bound(WaterList.begin(), WaterList.end(), NewBB,
- CompareMBBNumbers);
- WaterList.insert(IP, NewBB);
-}
-
-/// getUserOffset - Compute the offset of U.MI as seen by the hardware
-/// displacement computation. Update U.KnownAlignment to match its current
-/// basic block location.
-unsigned MipsConstantIslands::getUserOffset(CPUser &U) const {
- unsigned UserOffset = getOffsetOf(U.MI);
- const BasicBlockInfo &BBI = BBInfo[U.MI->getParent()->getNumber()];
- unsigned KnownBits = BBI.internalKnownBits();
-
- // The value read from PC is offset from the actual instruction address.
-#ifdef IN_PROGRESS
- UserOffset += (isThumb ? 4 : 8);
-#endif
-
- // Because of inline assembly, we may not know the alignment (mod 4) of U.MI.
- // Make sure U.getMaxDisp() returns a constrained range.
- U.KnownAlignment = (KnownBits >= 2);
-
- // On Thumb, offsets==2 mod 4 are rounded down by the hardware for
- // purposes of the displacement computation; compensate for that here.
- // For unknown alignments, getMaxDisp() constrains the range instead.
-#ifdef IN_PROGRESS
- if (isThumb && U.KnownAlignment)
- UserOffset &= ~3u;
-#endif
-
- return UserOffset;
-}
-
-/// Split the basic block containing MI into two blocks, which are joined by
-/// an unconditional branch. Update data structures and renumber blocks to
-/// account for this change and returns the newly created block.
-MachineBasicBlock *MipsConstantIslands::splitBlockBeforeInstr(MachineInstr *MI) {
- MachineBasicBlock *OrigBB = MI->getParent();
-
- // Create a new MBB for the code after the OrigBB.
- MachineBasicBlock *NewBB =
- MF->CreateMachineBasicBlock(OrigBB->getBasicBlock());
- MachineFunction::iterator MBBI = OrigBB; ++MBBI;
- MF->insert(MBBI, NewBB);
-
- // Splice the instructions starting with MI over to NewBB.
- NewBB->splice(NewBB->end(), OrigBB, MI, OrigBB->end());
-
- // Add an unconditional branch from OrigBB to NewBB.
- // 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(), TII->get(Mips::BimmX16)).addMBB(NewBB);
-#ifdef IN_PROGRESS
- unsigned Opc = isThumb ? (isThumb2 ? ARM::t2B : ARM::tB) : ARM::B;
- if (!isThumb)
- BuildMI(OrigBB, DebugLoc(), TII->get(Opc)).addMBB(NewBB);
- else
- BuildMI(OrigBB, DebugLoc(), TII->get(Opc)).addMBB(NewBB)
- .addImm(ARMCC::AL).addReg(0);
-#endif
- ++NumSplit;
-
- // Update the CFG. All succs of OrigBB are now succs of NewBB.
- NewBB->transferSuccessors(OrigBB);
-
- // OrigBB branches to NewBB.
- OrigBB->addSuccessor(NewBB);
-
- // Update internal data structures to account for the newly inserted MBB.
- // This is almost the same as updateForInsertedWaterBlock, except that
- // the Water goes after OrigBB, not NewBB.
- MF->RenumberBlocks(NewBB);
-
- // Insert an entry into BBInfo to align it properly with the (newly
- // renumbered) block numbers.
- BBInfo.insert(BBInfo.begin() + NewBB->getNumber(), BasicBlockInfo());
-
- // Next, update WaterList. Specifically, we need to add OrigMBB as having
- // 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).
- water_iterator IP =
- std::lower_bound(WaterList.begin(), WaterList.end(), OrigBB,
- CompareMBBNumbers);
- MachineBasicBlock* WaterBB = *IP;
- if (WaterBB == OrigBB)
- WaterList.insert(llvm::next(IP), NewBB);
- else
- WaterList.insert(IP, OrigBB);
- NewWaterList.insert(OrigBB);
-
- // Figure out how large the OrigBB is. As the first half of the original
- // block, it cannot contain a tablejump. The size includes
- // the new jump we added. (It should be possible to do this without
- // recounting everything, but it's very confusing, and this is rarely
- // executed.)
- computeBlockSize(OrigBB);
-
- // Figure out how large the NewMBB is. As the second half of the original
- // block, it may contain a tablejump.
- computeBlockSize(NewBB);
-
- // All BBOffsets following these blocks must be modified.
- adjustBBOffsetsAfter(OrigBB);
-
- return NewBB;
-}
-
-#ifndef NDEBUG
-
-
-/// isOffsetInRange - Checks whether UserOffset (the location of a constant pool
-/// reference) is within MaxDisp of TrialOffset (a proposed location of a
-/// constant pool entry).
-/// UserOffset is computed by getUserOffset above to include PC adjustments. If
-/// the mod 4 alignment of UserOffset is not known, the uncertainty must be
-/// subtracted from MaxDisp instead. CPUser::getMaxDisp() does that.
-bool MipsConstantIslands::isOffsetInRange(unsigned UserOffset,
- unsigned TrialOffset, unsigned MaxDisp,
- bool NegativeOK, bool IsSoImm) {
- if (UserOffset <= TrialOffset) {
- // User before the Trial.
- if (TrialOffset - UserOffset <= MaxDisp)
- return true;
- // FIXME: Make use full range of soimm values.
- } else if (NegativeOK) {
- if (UserOffset - TrialOffset <= MaxDisp)
- return true;
- // FIXME: Make use full range of soimm values.
- }
- return false;
-}
-
-/// isWaterInRange - Returns true if a CPE placed after the specified
-/// Water (a basic block) will be in range for the specific MI.
-///
-/// Compute how much the function will grow by inserting a CPE after Water.
-bool MipsConstantIslands::isWaterInRange(unsigned UserOffset,
- MachineBasicBlock* Water, CPUser &U,
- unsigned &Growth) {
- unsigned CPELogAlign = getCPELogAlign(U.CPEMI);
- unsigned CPEOffset = BBInfo[Water->getNumber()].postOffset(CPELogAlign);
- unsigned NextBlockOffset, NextBlockAlignment;
- MachineFunction::const_iterator NextBlock = Water;
- if (++NextBlock == MF->end()) {
- NextBlockOffset = BBInfo[Water->getNumber()].postOffset();
- NextBlockAlignment = 0;
- } else {
- NextBlockOffset = BBInfo[NextBlock->getNumber()].Offset;
- NextBlockAlignment = NextBlock->getAlignment();
- }
- unsigned Size = U.CPEMI->getOperand(2).getImm();
- unsigned CPEEnd = CPEOffset + Size;
-
- // The CPE may be able to hide in the alignment padding before the next
- // block. It may also cause more padding to be required if it is more aligned
- // that the next block.
- if (CPEEnd > NextBlockOffset) {
- Growth = CPEEnd - NextBlockOffset;
- // Compute the padding that would go at the end of the CPE to align the next
- // block.
- Growth += OffsetToAlignment(CPEEnd, 1u << NextBlockAlignment);
-
- // If the CPE is to be inserted before the instruction, that will raise
- // the offset of the instruction. Also account for unknown alignment padding
- // in blocks between CPE and the user.
- if (CPEOffset < UserOffset)
- UserOffset += Growth + UnknownPadding(MF->getAlignment(), CPELogAlign);
- } else
- // CPE fits in existing padding.
- Growth = 0;
-
- return isOffsetInRange(UserOffset, CPEOffset, U);
-}
-
-/// isCPEntryInRange - Returns true if the distance between specific MI and
-/// specific ConstPool entry instruction can fit in MI's displacement field.
-bool MipsConstantIslands::isCPEntryInRange(MachineInstr *MI, unsigned UserOffset,
- MachineInstr *CPEMI, unsigned MaxDisp,
- bool NegOk, bool DoDump) {
- unsigned CPEOffset = getOffsetOf(CPEMI);
-
- if (DoDump) {
- DEBUG({
- unsigned Block = MI->getParent()->getNumber();
- const BasicBlockInfo &BBI = BBInfo[Block];
- dbgs() << "User of CPE#" << CPEMI->getOperand(0).getImm()
- << " max delta=" << MaxDisp
- << format(" insn address=%#x", UserOffset)
- << " in BB#" << Block << ": "
- << format("%#x-%x\t", BBI.Offset, BBI.postOffset()) << *MI
- << format("CPE address=%#x offset=%+d: ", CPEOffset,
- int(CPEOffset-UserOffset));
- });
- }
-
- return isOffsetInRange(UserOffset, CPEOffset, MaxDisp, NegOk);
-}
-
-/// BBIsJumpedOver - Return true of the specified basic block's only predecessor
-/// unconditionally branches to its only successor.
-static bool BBIsJumpedOver(MachineBasicBlock *MBB) {
- if (MBB->pred_size() != 1 || MBB->succ_size() != 1)
- return false;
-
-#ifdef IN_PROGRESS
- MachineBasicBlock *Succ = *MBB->succ_begin();
- MachineBasicBlock *Pred = *MBB->pred_begin();
- MachineInstr *PredMI = &Pred->back();
- if (PredMI->getOpcode() == ARM::B || PredMI->getOpcode() == ARM::tB
- || PredMI->getOpcode() == ARM::t2B)
- return PredMI->getOperand(0).getMBB() == Succ;
-#endif
- return false;
-}
-#endif // NDEBUG
-
-void MipsConstantIslands::adjustBBOffsetsAfter(MachineBasicBlock *BB) {
- unsigned BBNum = BB->getNumber();
- for(unsigned i = BBNum + 1, e = MF->getNumBlockIDs(); i < e; ++i) {
- // Get the offset and known bits at the end of the layout predecessor.
- // Include the alignment of the current block.
- unsigned Offset = BBInfo[i - 1].postOffset();
- BBInfo[i].Offset = Offset;
- }
-}
-
-/// decrementCPEReferenceCount - find the constant pool entry with index CPI
-/// and instruction CPEMI, and decrement its refcount. If the refcount
-/// becomes 0 remove the entry and instruction. Returns true if we removed
-/// the entry, false if we didn't.
-
-bool MipsConstantIslands::decrementCPEReferenceCount(unsigned CPI,
- MachineInstr *CPEMI) {
- // Find the old entry. Eliminate it if it is no longer used.
- CPEntry *CPE = findConstPoolEntry(CPI, CPEMI);
- assert(CPE && "Unexpected!");
- if (--CPE->RefCount == 0) {
- removeDeadCPEMI(CPEMI);
- CPE->CPEMI = NULL;
- --NumCPEs;
- return true;
- }
- return false;
-}
-
-/// LookForCPEntryInRange - see if the currently referenced CPE is in range;
-/// if not, see if an in-range clone of the CPE is in range, and if so,
-/// change the data structures so the user references the clone. Returns:
-/// 0 = no existing entry found
-/// 1 = entry found, and there were no code insertions or deletions
-/// 2 = entry found, and there were code insertions or deletions
-int MipsConstantIslands::findInRangeCPEntry(CPUser& U, unsigned UserOffset)
-{
- MachineInstr *UserMI = U.MI;
- MachineInstr *CPEMI = U.CPEMI;
-
- // Check to see if the CPE is already in-range.
- if (isCPEntryInRange(UserMI, UserOffset, CPEMI, U.getMaxDisp(), U.NegOk,
- true)) {
- DEBUG(dbgs() << "In range\n");
- return 1;
- }
-
- // No. Look for previously created clones of the CPE that are in range.
- unsigned CPI = CPEMI->getOperand(1).getIndex();
- std::vector<CPEntry> &CPEs = CPEntries[CPI];
- for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
- // We already tried this one
- if (CPEs[i].CPEMI == CPEMI)
- continue;
- // Removing CPEs can leave empty entries, skip
- if (CPEs[i].CPEMI == NULL)
- continue;
- if (isCPEntryInRange(UserMI, UserOffset, CPEs[i].CPEMI, U.getMaxDisp(),
- U.NegOk)) {
- DEBUG(dbgs() << "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.
- for (unsigned j = 0, e = UserMI->getNumOperands(); j != e; ++j)
- if (UserMI->getOperand(j).isCPI()) {
- UserMI->getOperand(j).setIndex(CPEs[i].CPI);
- break;
- }
- // Adjust the refcount of the clone...
- CPEs[i].RefCount++;
- // ...and the original. If we didn't remove the old entry, none of the
- // addresses changed, so we don't need another pass.
- return decrementCPEReferenceCount(CPI, CPEMI) ? 2 : 1;
- }
- }
- return 0;
-}
-
-/// LookForCPEntryInRange - see if the currently referenced CPE is in range;
-/// This version checks if the longer form of the instruction can be used to
-/// to satisfy things.
-/// if not, see if an in-range clone of the CPE is in range, and if so,
-/// change the data structures so the user references the clone. Returns:
-/// 0 = no existing entry found
-/// 1 = entry found, and there were no code insertions or deletions
-/// 2 = entry found, and there were code insertions or deletions
-int MipsConstantIslands::findLongFormInRangeCPEntry(CPUser& U, unsigned UserOffset)
-{
- MachineInstr *UserMI = U.MI;
- MachineInstr *CPEMI = U.CPEMI;
-
- // Check to see if the CPE is already in-range.
- if (isCPEntryInRange(UserMI, UserOffset, CPEMI, U.getLongFormMaxDisp(), U.NegOk,
- true)) {
- DEBUG(dbgs() << "In range\n");
- UserMI->setDesc(TII->get(U.getLongFormOpcode()));
- return 2; // instruction is longer length now
- }
-
- // No. Look for previously created clones of the CPE that are in range.
- unsigned CPI = CPEMI->getOperand(1).getIndex();
- std::vector<CPEntry> &CPEs = CPEntries[CPI];
- for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
- // We already tried this one
- if (CPEs[i].CPEMI == CPEMI)
- continue;
- // Removing CPEs can leave empty entries, skip
- if (CPEs[i].CPEMI == NULL)
- continue;
- if (isCPEntryInRange(UserMI, UserOffset, CPEs[i].CPEMI, U.getLongFormMaxDisp(),
- U.NegOk)) {
- DEBUG(dbgs() << "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.
- for (unsigned j = 0, e = UserMI->getNumOperands(); j != e; ++j)
- if (UserMI->getOperand(j).isCPI()) {
- UserMI->getOperand(j).setIndex(CPEs[i].CPI);
- break;
- }
- // Adjust the refcount of the clone...
- CPEs[i].RefCount++;
- // ...and the original. If we didn't remove the old entry, none of the
- // addresses changed, so we don't need another pass.
- return decrementCPEReferenceCount(CPI, CPEMI) ? 2 : 1;
- }
- }
- return 0;
-}
-
-/// getUnconditionalBrDisp - Returns the maximum displacement that can fit in
-/// the specific unconditional branch instruction.
-static inline unsigned getUnconditionalBrDisp(int Opc) {
-#ifdef IN_PROGRESS
- switch (Opc) {
- case ARM::tB:
- return ((1<<10)-1)*2;
- case ARM::t2B:
- return ((1<<23)-1)*2;
- default:
- break;
- }
-#endif
- return ((1<<23)-1)*4;
-}
-
-/// findAvailableWater - 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, WaterIter
-/// 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 MipsConstantIslands::findAvailableWater(CPUser &U, unsigned UserOffset,
- water_iterator &WaterIter) {
- if (WaterList.empty())
- return false;
-
- unsigned BestGrowth = ~0u;
- for (water_iterator IP = prior(WaterList.end()), B = WaterList.begin();;
- --IP) {
- MachineBasicBlock* WaterBB = *IP;
- // Check if water is in range and is either at a lower address than the
- // current "high water mark" or a new water block that was created since
- // the previous iteration by inserting an unconditional branch. In the
- // latter case, we want to allow resetting the high water mark back to
- // this new water since we haven't seen it before. Inserting branches
- // should be relatively uncommon and when it does happen, we want to be
- // sure to take advantage of it for all the CPEs near that block, so that
- // we don't insert more branches than necessary.
- unsigned Growth;
- if (isWaterInRange(UserOffset, WaterBB, U, Growth) &&
- (WaterBB->getNumber() < U.HighWaterMark->getNumber() ||
- NewWaterList.count(WaterBB)) && Growth < BestGrowth) {
- // This is the least amount of required padding seen so far.
- BestGrowth = Growth;
- WaterIter = IP;
- DEBUG(dbgs() << "Found water after BB#" << WaterBB->getNumber()
- << " Growth=" << Growth << '\n');
-
- // Keep looking unless it is perfect.
- if (BestGrowth == 0)
- return true;
- }
- if (IP == B)
- break;
- }
- return BestGrowth != ~0u;
-}
-
-/// createNewWater - No existing WaterList entry will work for
-/// 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
-/// block following which the new island can be inserted (the WaterList
-/// is not adjusted).
-void MipsConstantIslands::createNewWater(unsigned CPUserIndex,
- unsigned UserOffset,
- MachineBasicBlock *&NewMBB) {
- CPUser &U = CPUsers[CPUserIndex];
- MachineInstr *UserMI = U.MI;
- MachineInstr *CPEMI = U.CPEMI;
- unsigned CPELogAlign = getCPELogAlign(CPEMI);
- MachineBasicBlock *UserMBB = UserMI->getParent();
- const BasicBlockInfo &UserBBI = BBInfo[UserMBB->getNumber()];
-
- // If the block does not end in an unconditional branch already, and if 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 +
- // Thumb2, 2 on Thumb1.
- if (BBHasFallthrough(UserMBB)) {
- // Size of branch to insert.
-#ifdef IN_PROGRESS
- unsigned Delta = isThumb1 ? 2 : 4;
-#else
- unsigned Delta = 4;
-#endif
- // Compute the offset where the CPE will begin.
- unsigned CPEOffset = UserBBI.postOffset(CPELogAlign) + Delta;
-
- if (isOffsetInRange(UserOffset, CPEOffset, U)) {
- DEBUG(dbgs() << "Split at end of BB#" << UserMBB->getNumber()
- << format(", expected CPE offset %#x\n", CPEOffset));
- NewMBB = llvm::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 targets
- // will be exchanged, and the altered branch may be out of range, so the
- // machinery has to know about it.
-#ifdef IN_PROGRESS
- int UncondBr = isThumb ? ((isThumb2) ? ARM::t2B : ARM::tB) : ARM::B;
- if (!isThumb)
- BuildMI(UserMBB, DebugLoc(), TII->get(UncondBr)).addMBB(NewMBB);
- else
- BuildMI(UserMBB, DebugLoc(), TII->get(UncondBr)).addMBB(NewMBB)
- .addImm(ARMCC::AL).addReg(0);
-#else
- int UncondBr = 1;
-#endif
- unsigned MaxDisp = getUnconditionalBrDisp(UncondBr);
- ImmBranches.push_back(ImmBranch(&UserMBB->back(),
- MaxDisp, false, UncondBr));
- BBInfo[UserMBB->getNumber()].Size += Delta;
- adjustBBOffsetsAfter(UserMBB);
- return;
- }
- }
-
- // What a big block. Find a place within the block to split it. 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 CPE' cannot immediately follow it (that
- // location is 2 bytes farther away from I+1 than CPE was from I) and we'd
- // need to create a new island. So, we make a first guess, then walk through
- // the instructions between the one currently being looked at and the
- // possible insertion point, and make sure any other instructions that
- // reference CPEs will be able to use the same island area; if not, we back
- // up the insertion point.
-
- // Try to split the block so it's fully aligned. Compute the latest split
- // point where we can add a 4-byte branch instruction, and then align to
- // LogAlign which is the largest possible alignment in the function.
- unsigned LogAlign = MF->getAlignment();
- assert(LogAlign >= CPELogAlign && "Over-aligned constant pool entry");
- unsigned KnownBits = UserBBI.internalKnownBits();
- unsigned UPad = UnknownPadding(LogAlign, KnownBits);
- unsigned BaseInsertOffset = UserOffset + U.getMaxDisp() - UPad;
- DEBUG(dbgs() << format("Split in middle of big block before %#x",
- BaseInsertOffset));
-
- // The 4 in the following is for the unconditional branch we'll be inserting
- // (allows for long branch on Thumb1). Alignment of the island is handled
- // inside isOffsetInRange.
- BaseInsertOffset -= 4;
-
- DEBUG(dbgs() << format(", adjusted to %#x", BaseInsertOffset)
- << " la=" << LogAlign
- << " kb=" << KnownBits
- << " up=" << UPad << '\n');
-
- // This could point off the end of the block if we've already got constant
- // pool entries following this block; only the last one is in the water list.
- // Back past any possible branches (allow for a conditional and a maximally
- // long unconditional).
- if (BaseInsertOffset + 8 >= UserBBI.postOffset()) {
- BaseInsertOffset = UserBBI.postOffset() - UPad - 8;
- DEBUG(dbgs() << format("Move inside block: %#x\n", BaseInsertOffset));
- }
- unsigned EndInsertOffset = BaseInsertOffset + 4 + UPad +
- CPEMI->getOperand(2).getImm();
- MachineBasicBlock::iterator MI = UserMI;
- ++MI;
- unsigned CPUIndex = CPUserIndex+1;
- unsigned NumCPUsers = CPUsers.size();
- MachineInstr *LastIT = 0;
- for (unsigned Offset = UserOffset+TII->GetInstSizeInBytes(UserMI);
- Offset < BaseInsertOffset;
- Offset += TII->GetInstSizeInBytes(MI),
- MI = llvm::next(MI)) {
- assert(MI != UserMBB->end() && "Fell off end of block");
- if (CPUIndex < NumCPUsers && CPUsers[CPUIndex].MI == MI) {
- CPUser &U = CPUsers[CPUIndex];
- if (!isOffsetInRange(Offset, EndInsertOffset, U)) {
- // Shift intertion point by one unit of alignment so it is within reach.
- BaseInsertOffset -= 1u << LogAlign;
- EndInsertOffset -= 1u << LogAlign;
- }
- // This is overly conservative, as we don't account for CPEMIs being
- // reused within the block, but it doesn't matter much. Also assume CPEs
- // are added in order with alignment padding. We may eventually be able
- // to pack the aligned CPEs better.
- EndInsertOffset += U.CPEMI->getOperand(2).getImm();
- CPUIndex++;
- }
-#ifdef IN_PROGRESS
- // Remember the last IT instruction.
- if (MI->getOpcode() == ARM::t2IT)
- LastIT = MI;
-#endif
- }
-
- --MI;
-
- // Avoid splitting an IT block.
- if (LastIT) {
-#ifdef IN_PROGRESS
- unsigned PredReg = 0;
- ARMCC::CondCodes CC = getITInstrPredicate(MI, PredReg);
- if (CC != ARMCC::AL)
- MI = LastIT;
-#endif
- }
- NewMBB = splitBlockBeforeInstr(MI);
-}
-
-/// handleConstantPoolUser - Analyze the specified user, checking to see if it
-/// 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 MipsConstantIslands::handleConstantPoolUser(unsigned CPUserIndex) {
- CPUser &U = CPUsers[CPUserIndex];
- MachineInstr *UserMI = U.MI;
- MachineInstr *CPEMI = U.CPEMI;
- unsigned CPI = CPEMI->getOperand(1).getIndex();
- unsigned Size = CPEMI->getOperand(2).getImm();
- // Compute this only once, it's expensive.
- unsigned UserOffset = getUserOffset(U);
-
- // See if the current entry is within range, or there is a clone of it
- // in range.
- int result = findInRangeCPEntry(U, UserOffset);
- if (result==1) return false;
- else if (result==2) return true;
-
-
- // Look for water where we can place this CPE.
- MachineBasicBlock *NewIsland = MF->CreateMachineBasicBlock();
- MachineBasicBlock *NewMBB;
- water_iterator IP;
- if (findAvailableWater(U, UserOffset, IP)) {
- DEBUG(dbgs() << "Found water in range\n");
- MachineBasicBlock *WaterBB = *IP;
-
- // If the original WaterList entry was "new water" on this iteration,
- // propagate that to the new island. This is just keeping NewWaterList
- // updated to match the WaterList, which will be updated below.
- if (NewWaterList.erase(WaterBB))
- NewWaterList.insert(NewIsland);
-
- // The new CPE goes before the following block (NewMBB).
- NewMBB = llvm::next(MachineFunction::iterator(WaterBB));
-
- } else {
- // No water found.
- // we first see if a longer form of the instrucion could have reached the constant.
- // in that case we won't bother to split
-#ifdef IN_PROGRESS
- result = findLongFormInRangeCPEntry(U, UserOffset);
-#endif
- DEBUG(dbgs() << "No water found\n");
- createNewWater(CPUserIndex, UserOffset, NewMBB);
-
- // splitBlockBeforeInstr adds to WaterList, which is important when it is
- // called while handling branches so that the water will be seen on the
- // next iteration for constant pools, but in this context, we don't want
- // it. Check for this so it will be removed from the WaterList.
- // Also remove any entry from NewWaterList.
- MachineBasicBlock *WaterBB = prior(MachineFunction::iterator(NewMBB));
- IP = std::find(WaterList.begin(), WaterList.end(), WaterBB);
- if (IP != WaterList.end())
- NewWaterList.erase(WaterBB);
-
- // We are adding new water. Update NewWaterList.
- NewWaterList.insert(NewIsland);
- }
-
- // 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 of times we have to move the same CPE
- // more than once and is also important to ensure the algorithm terminates.
- if (IP != WaterList.end())
- WaterList.erase(IP);
-
- // Okay, we know we can put an island before NewMBB now, do it!
- MF->insert(NewMBB, NewIsland);
-
- // Update internal data structures to account for the newly inserted MBB.
- updateForInsertedWaterBlock(NewIsland);
-
- // Decrement the old entry, and remove it if refcount becomes 0.
- decrementCPEReferenceCount(CPI, CPEMI);
-
- // Now that we have an island to add the CPE to, clone the original CPE and
- // add it to the island.
- U.HighWaterMark = NewIsland;
- U.CPEMI = BuildMI(NewIsland, DebugLoc(), TII->get(Mips::CONSTPOOL_ENTRY))
- .addImm(ID).addConstantPoolIndex(CPI).addImm(Size);
- CPEntries[CPI].push_back(CPEntry(U.CPEMI, ID, 1));
- ++NumCPEs;
-
- // Mark the basic block as aligned as required by the const-pool entry.
- NewIsland->setAlignment(getCPELogAlign(U.CPEMI));
-
- // Increase the size of the island block to account for the new entry.
- BBInfo[NewIsland->getNumber()].Size += Size;
- adjustBBOffsetsAfter(llvm::prior(MachineFunction::iterator(NewIsland)));
-
- // No existing clone of this CPE is within range.
- // We will be generating a new clone. Get a UID for it.
- unsigned ID = createPICLabelUId();
-
- // Finally, change the CPI in the instruction operand to be ID.
- for (unsigned i = 0, e = UserMI->getNumOperands(); i != e; ++i)
- if (UserMI->getOperand(i).isCPI()) {
- UserMI->getOperand(i).setIndex(ID);
- break;
- }
-
- DEBUG(dbgs() << " Moved CPE to #" << ID << " CPI=" << CPI
- << format(" offset=%#x\n", BBInfo[NewIsland->getNumber()].Offset));
-
- return true;
-}
-
-/// removeDeadCPEMI - Remove a dead constant pool entry instruction. Update
-/// sizes and offsets of impacted basic blocks.
-void MipsConstantIslands::removeDeadCPEMI(MachineInstr *CPEMI) {
- MachineBasicBlock *CPEBB = CPEMI->getParent();
- unsigned Size = CPEMI->getOperand(2).getImm();
- CPEMI->eraseFromParent();
- BBInfo[CPEBB->getNumber()].Size -= Size;
- // All succeeding offsets have the current size value added in, fix this.
- if (CPEBB->empty()) {
- BBInfo[CPEBB->getNumber()].Size = 0;
-
- // This block no longer needs to be aligned.
- CPEBB->setAlignment(0);
- } else
- // Entries are sorted by descending alignment, so realign from the front.
- CPEBB->setAlignment(getCPELogAlign(CPEBB->begin()));
-
- adjustBBOffsetsAfter(CPEBB);
- // An island has only one predecessor BB and one successor BB. Check if
- // this BB's predecessor jumps directly to this BB's successor. This
- // shouldn't happen currently.
- assert(!BBIsJumpedOver(CPEBB) && "How did this happen?");
- // FIXME: remove the empty blocks after all the work is done?
-}
-
-/// removeUnusedCPEntries - Remove constant pool entries whose refcounts
-/// are zero.
-bool MipsConstantIslands::removeUnusedCPEntries() {
- unsigned MadeChange = false;
- for (unsigned i = 0, e = CPEntries.size(); i != e; ++i) {
- std::vector<CPEntry> &CPEs = CPEntries[i];
- for (unsigned j = 0, ee = CPEs.size(); j != ee; ++j) {
- if (CPEs[j].RefCount == 0 && CPEs[j].CPEMI) {
- removeDeadCPEMI(CPEs[j].CPEMI);
- CPEs[j].CPEMI = NULL;
- MadeChange = true;
- }
- }
- }
- return MadeChange;
-}
-
-/// isBBInRange - Returns true if the distance between specific MI and
-/// specific BB can fit in MI's displacement field.
-bool MipsConstantIslands::isBBInRange(MachineInstr *MI,MachineBasicBlock *DestBB,
- unsigned MaxDisp) {
-#ifdef IN_PROGRESS
- unsigned PCAdj = isThumb ? 4 : 8;
-#else
- unsigned PCAdj = 4;
-#endif
- unsigned BrOffset = getOffsetOf(MI) + PCAdj;
- unsigned DestOffset = BBInfo[DestBB->getNumber()].Offset;
-
- DEBUG(dbgs() << "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.
- if (DestOffset-BrOffset <= MaxDisp)
- return true;
- } else {
- if (BrOffset-DestOffset <= MaxDisp)
- return true;
- }
- return false;
-}
-
-/// fixupImmediateBr - Fix up an immediate branch whose destination is too far
-/// away to fit in its displacement field.
-bool MipsConstantIslands::fixupImmediateBr(ImmBranch &Br) {
- MachineInstr *MI = Br.MI;
- MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
-
- // Check to see if the DestBB is already in-range.
- if (isBBInRange(MI, DestBB, Br.MaxDisp))
- return false;
-
- if (!Br.isCond)
- return fixupUnconditionalBr(Br);
- return fixupConditionalBr(Br);
-}
-
-/// fixupUnconditionalBr - Fix up an unconditional branch whose destination is
-/// too far away to fit in its displacement field. If the LR register has been
-/// spilled in the epilogue, then we can use BL to implement a far jump.
-/// Otherwise, add an intermediate branch instruction to a branch.
-bool
-MipsConstantIslands::fixupUnconditionalBr(ImmBranch &Br) {
- MachineInstr *MI = Br.MI;
- MachineBasicBlock *MBB = MI->getParent();
-#ifdef IN_PROGRESS
- if (!isThumb1)
- llvm_unreachable("fixupUnconditionalBr is Thumb1 only!");
-#endif
- // Use BL to implement far jump.
- Br.MaxDisp = (1 << 21) * 2;
-#ifdef IN_PROGRESS
- MI->setDesc(TII->get(ARM::tBfar));
-#endif
- BBInfo[MBB->getNumber()].Size += 2;
- adjustBBOffsetsAfter(MBB);
- HasFarJump = true;
- ++NumUBrFixed;
-
- DEBUG(dbgs() << " Changed B to long jump " << *MI);
-
- return true;
-}
-
-/// fixupConditionalBr - Fix up a conditional branch whose destination is too
-/// far away to fit in its displacement field. It is converted to an inverse
-/// conditional branch + an unconditional branch to the destination.
-bool
-MipsConstantIslands::fixupConditionalBr(ImmBranch &Br) {
-#ifdef IN_PROGRESS
- MachineInstr *MI = Br.MI;
- MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
-
- // Add an unconditional branch to the destination and invert the branch
- // condition to jump over it:
- // blt L1
- // =>
- // bge L2
- // b L1
- // L2:
- ARMCC::CondCodes CC = (ARMCC::CondCodes)MI->getOperand(1).getImm();
- CC = ARMCC::getOppositeCondition(CC);
- unsigned CCReg = MI->getOperand(2).getReg();
-
- // If the branch is at the end of its MBB and that has a fall-through block,
- // direct the updated conditional branch to the fall-through block. Otherwise,
- // split the MBB before the next instruction.
- MachineBasicBlock *MBB = MI->getParent();
- MachineInstr *BMI = &MBB->back();
- bool NeedSplit = (BMI != MI) || !BBHasFallthrough(MBB);
-
- ++NumCBrFixed;
- if (BMI != MI) {
- if (llvm::next(MachineBasicBlock::iterator(MI)) == prior(MBB->end()) &&
- BMI->getOpcode() == Br.UncondBr) {
- // Last MI in the BB is an unconditional branch. Can we simply invert the
- // condition and swap destinations:
- // beq L1
- // b L2
- // =>
- // bne L2
- // b L1
- MachineBasicBlock *NewDest = BMI->getOperand(0).getMBB();
- if (isBBInRange(MI, NewDest, Br.MaxDisp)) {
- DEBUG(dbgs() << " Invert Bcc condition and swap its destination with "
- << *BMI);
- BMI->getOperand(0).setMBB(DestBB);
- MI->getOperand(0).setMBB(NewDest);
- MI->getOperand(1).setImm(CC);
- return true;
- }
- }
- }
-
- if (NeedSplit) {
- splitBlockBeforeInstr(MI);
- // No need for the branch to the next block. We're adding an unconditional
- // branch to the destination.
- int delta = TII->GetInstSizeInBytes(&MBB->back());
- BBInfo[MBB->getNumber()].Size -= delta;
- MBB->back().eraseFromParent();
- // BBInfo[SplitBB].Offset is wrong temporarily, fixed below
- }
- MachineBasicBlock *NextBB = llvm::next(MachineFunction::iterator(MBB));
-
- DEBUG(dbgs() << " 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.
- BuildMI(MBB, DebugLoc(), TII->get(MI->getOpcode()))
- .addMBB(NextBB).addImm(CC).addReg(CCReg);
- Br.MI = &MBB->back();
- BBInfo[MBB->getNumber()].Size += TII->GetInstSizeInBytes(&MBB->back());
- if (isThumb)
- BuildMI(MBB, DebugLoc(), TII->get(Br.UncondBr)).addMBB(DestBB)
- .addImm(ARMCC::AL).addReg(0);
- else
- BuildMI(MBB, DebugLoc(), TII->get(Br.UncondBr)).addMBB(DestBB);
- BBInfo[MBB->getNumber()].Size += TII->GetInstSizeInBytes(&MBB->back());
- unsigned MaxDisp = getUnconditionalBrDisp(Br.UncondBr);
- ImmBranches.push_back(ImmBranch(&MBB->back(), MaxDisp, false, Br.UncondBr));
-
- // Remove the old conditional branch. It may or may not still be in MBB.
- BBInfo[MI->getParent()->getNumber()].Size -= TII->GetInstSizeInBytes(MI);
- MI->eraseFromParent();
- adjustBBOffsetsAfter(MBB);
-#endif
- return true;
-}
-
void MipsConstantIslands::prescanForConstants() {
unsigned int J;
- PrescannedForConstants = true;
for (MachineFunction::iterator B =
MF->begin(), E = MF->end(); B != E; ++B) {
for (MachineBasicBlock::instr_iterator I =
@@ -1715,11 +238,10 @@ void MipsConstantIslands::prescanForCons
unsigned index = MCP->getConstantPoolIndex(C, 4);
I->getOperand(2).ChangeToImmediate(index);
DEBUG(dbgs() << "constant island constant " << *I << "\n");
- I->setDesc(TII->get(Mips::LwRxPcTcp16));
+ I->setDesc(TII->get(Mips::LwRxPcTcpX16));
I->RemoveOperand(1);
I->RemoveOperand(1);
I->addOperand(MachineOperand::CreateCPI(index, 0));
- I->addOperand(MachineOperand::CreateImm(4));
}
break;
}
@@ -1729,4 +251,3 @@ void MipsConstantIslands::prescanForCons
}
}
}
-
Removed: llvm/trunk/test/CodeGen/Mips/const4.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Mips/const4.ll?rev=194025&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Mips/const4.ll (original)
+++ llvm/trunk/test/CodeGen/Mips/const4.ll (removed)
@@ -1,64 +0,0 @@
-; RUN: llc -mtriple=mipsel-linux-gnu -march=mipsel -mcpu=mips16 -soft-float -mips16-hard-float -relocation-model=static -mips16-constant-islands -mips-constant-islands-small-offset=20 < %s | FileCheck %s -check-prefix=offset20
-
-; RUN: llc -mtriple=mipsel-linux-gnu -march=mipsel -mcpu=mips16 -soft-float -mips16-hard-float -relocation-model=static -mips16-constant-islands -mips-constant-islands-small-offset=40 < %s | FileCheck %s -check-prefix=offset40
-
-
- at i = common global i32 0, align 4
- at b = common global i32 0, align 4
-
-; Function Attrs: nounwind
-define void @t() #0 {
-entry:
- store i32 -559023410, i32* @i, align 4
- %0 = load i32* @b, align 4
- %tobool = icmp ne i32 %0, 0
- br i1 %tobool, label %if.then, label %if.else
-; offset20: lw ${{[0-9]+}}, $CPI0_1 # 16 bit inst
-; offset20: b $BB0_2
-; offset20: .align 2
-; offset20: $CPI0_0:
-; offset20: .4byte 3735943886
-; offset20: $BB0_2:
-
-; offset40: beqz ${{[0-9]+}}, $BB0_3
-; offset40: jal foo
-; offset40: nop
-; offset40: b $BB0_4
-; offset40: .align 2
-; offset40: $CPI0_0:
-; offset40: .4byte 3735943886
-; offset40: $BB0_3:
-; offset40: jal goo
-
-if.then: ; preds = %entry
- call void bitcast (void (...)* @foo to void ()*)()
- br label %if.end
-
-if.else: ; preds = %entry
- call void bitcast (void (...)* @goo to void ()*)()
- br label %if.end
-
-if.end: ; preds = %if.else, %if.then
- call void bitcast (void (...)* @hoo to void ()*)()
- call void bitcast (void (...)* @hoo to void ()*)()
- call void bitcast (void (...)* @hoo to void ()*)()
- call void bitcast (void (...)* @hoo to void ()*)()
- call void bitcast (void (...)* @hoo to void ()*)()
- call void bitcast (void (...)* @hoo to void ()*)()
- call void bitcast (void (...)* @hoo to void ()*)()
- call void bitcast (void (...)* @hoo to void ()*)()
- ret void
-}
-
-declare void @foo(...) #1
-
-declare void @goo(...) #1
-
-declare void @hoo(...) #1
-
-attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="true" }
-attributes #1 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="true" }
-
-!llvm.ident = !{!0}
-
-!0 = metadata !{metadata !"clang version 3.4 (gitosis at dmz-portal.mips.com:clang.git 3a50d847e098f36e3bf8bc14eea07a6cc35f7803) (gitosis at dmz-portal.mips.com:llvm.git f52db0b69f0c888bdc98bb2f13aaecc1e83288a9)"}
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