mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-17 03:30:28 +00:00
d04a8d4b33
Sooooo many of these had incorrect or strange main module includes. I have manually inspected all of these, and fixed the main module include to be the nearest plausible thing I could find. If you own or care about any of these source files, I encourage you to take some time and check that these edits were sensible. I can't have broken anything (I strictly added headers, and reordered them, never removed), but they may not be the headers you'd really like to identify as containing the API being implemented. Many forward declarations and missing includes were added to a header files to allow them to parse cleanly when included first. The main module rule does in fact have its merits. =] git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
237 lines
7.8 KiB
C++
237 lines
7.8 KiB
C++
//===-- HexagonCFGOptimizer.cpp - CFG optimizations -----------------------===//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "hexagon_cfg"
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#include "Hexagon.h"
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#include "HexagonMachineFunctionInfo.h"
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#include "HexagonSubtarget.h"
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#include "HexagonTargetMachine.h"
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#include "llvm/CodeGen/MachineDominators.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineLoopInfo.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/MathExtras.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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using namespace llvm;
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namespace {
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class HexagonCFGOptimizer : public MachineFunctionPass {
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private:
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HexagonTargetMachine& QTM;
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const HexagonSubtarget &QST;
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void InvertAndChangeJumpTarget(MachineInstr*, MachineBasicBlock*);
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public:
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static char ID;
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HexagonCFGOptimizer(HexagonTargetMachine& TM) : MachineFunctionPass(ID),
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QTM(TM),
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QST(*TM.getSubtargetImpl()) {}
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const char *getPassName() const {
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return "Hexagon CFG Optimizer";
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}
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bool runOnMachineFunction(MachineFunction &Fn);
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};
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char HexagonCFGOptimizer::ID = 0;
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static bool IsConditionalBranch(int Opc) {
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return (Opc == Hexagon::JMP_c) || (Opc == Hexagon::JMP_cNot)
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|| (Opc == Hexagon::JMP_cdnPt) || (Opc == Hexagon::JMP_cdnNotPt);
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}
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static bool IsUnconditionalJump(int Opc) {
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return (Opc == Hexagon::JMP);
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}
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void
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HexagonCFGOptimizer::InvertAndChangeJumpTarget(MachineInstr* MI,
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MachineBasicBlock* NewTarget) {
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const HexagonInstrInfo *QII = QTM.getInstrInfo();
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int NewOpcode = 0;
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switch(MI->getOpcode()) {
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case Hexagon::JMP_c:
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NewOpcode = Hexagon::JMP_cNot;
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break;
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case Hexagon::JMP_cNot:
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NewOpcode = Hexagon::JMP_c;
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break;
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case Hexagon::JMP_cdnPt:
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NewOpcode = Hexagon::JMP_cdnNotPt;
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break;
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case Hexagon::JMP_cdnNotPt:
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NewOpcode = Hexagon::JMP_cdnPt;
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break;
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default:
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llvm_unreachable("Cannot handle this case");
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}
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MI->setDesc(QII->get(NewOpcode));
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MI->getOperand(1).setMBB(NewTarget);
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}
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bool HexagonCFGOptimizer::runOnMachineFunction(MachineFunction &Fn) {
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// Loop over all of the basic blocks.
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for (MachineFunction::iterator MBBb = Fn.begin(), MBBe = Fn.end();
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MBBb != MBBe; ++MBBb) {
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MachineBasicBlock* MBB = MBBb;
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// Traverse the basic block.
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MachineBasicBlock::iterator MII = MBB->getFirstTerminator();
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if (MII != MBB->end()) {
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MachineInstr *MI = MII;
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int Opc = MI->getOpcode();
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if (IsConditionalBranch(Opc)) {
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//
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// (Case 1) Transform the code if the following condition occurs:
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// BB1: if (p0) jump BB3
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// ...falls-through to BB2 ...
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// BB2: jump BB4
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// ...next block in layout is BB3...
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// BB3: ...
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//
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// Transform this to:
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// BB1: if (!p0) jump BB4
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// Remove BB2
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// BB3: ...
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//
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// (Case 2) A variation occurs when BB3 contains a JMP to BB4:
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// BB1: if (p0) jump BB3
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// ...falls-through to BB2 ...
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// BB2: jump BB4
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// ...other basic blocks ...
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// BB4:
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// ...not a fall-thru
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// BB3: ...
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// jump BB4
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//
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// Transform this to:
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// BB1: if (!p0) jump BB4
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// Remove BB2
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// BB3: ...
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// BB4: ...
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//
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unsigned NumSuccs = MBB->succ_size();
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MachineBasicBlock::succ_iterator SI = MBB->succ_begin();
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MachineBasicBlock* FirstSucc = *SI;
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MachineBasicBlock* SecondSucc = *(++SI);
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MachineBasicBlock* LayoutSucc = NULL;
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MachineBasicBlock* JumpAroundTarget = NULL;
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if (MBB->isLayoutSuccessor(FirstSucc)) {
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LayoutSucc = FirstSucc;
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JumpAroundTarget = SecondSucc;
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} else if (MBB->isLayoutSuccessor(SecondSucc)) {
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LayoutSucc = SecondSucc;
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JumpAroundTarget = FirstSucc;
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} else {
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// Odd case...cannot handle.
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}
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// The target of the unconditional branch must be JumpAroundTarget.
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// TODO: If not, we should not invert the unconditional branch.
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MachineBasicBlock* CondBranchTarget = NULL;
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if ((MI->getOpcode() == Hexagon::JMP_c) ||
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(MI->getOpcode() == Hexagon::JMP_cNot)) {
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CondBranchTarget = MI->getOperand(1).getMBB();
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}
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if (!LayoutSucc || (CondBranchTarget != JumpAroundTarget)) {
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continue;
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}
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if ((NumSuccs == 2) && LayoutSucc && (LayoutSucc->pred_size() == 1)) {
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// Ensure that BB2 has one instruction -- an unconditional jump.
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if ((LayoutSucc->size() == 1) &&
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IsUnconditionalJump(LayoutSucc->front().getOpcode())) {
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MachineBasicBlock* UncondTarget =
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LayoutSucc->front().getOperand(0).getMBB();
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// Check if the layout successor of BB2 is BB3.
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bool case1 = LayoutSucc->isLayoutSuccessor(JumpAroundTarget);
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bool case2 = JumpAroundTarget->isSuccessor(UncondTarget) &&
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JumpAroundTarget->size() >= 1 &&
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IsUnconditionalJump(JumpAroundTarget->back().getOpcode()) &&
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JumpAroundTarget->pred_size() == 1 &&
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JumpAroundTarget->succ_size() == 1;
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if (case1 || case2) {
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InvertAndChangeJumpTarget(MI, UncondTarget);
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MBB->removeSuccessor(JumpAroundTarget);
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MBB->addSuccessor(UncondTarget);
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// Remove the unconditional branch in LayoutSucc.
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LayoutSucc->erase(LayoutSucc->begin());
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LayoutSucc->removeSuccessor(UncondTarget);
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LayoutSucc->addSuccessor(JumpAroundTarget);
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// This code performs the conversion for case 2, which moves
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// the block to the fall-thru case (BB3 in the code above).
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if (case2 && !case1) {
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JumpAroundTarget->moveAfter(LayoutSucc);
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// only move a block if it doesn't have a fall-thru. otherwise
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// the CFG will be incorrect.
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if (!UncondTarget->canFallThrough()) {
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UncondTarget->moveAfter(JumpAroundTarget);
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}
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}
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//
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// Correct live-in information. Is used by post-RA scheduler
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// The live-in to LayoutSucc is now all values live-in to
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// JumpAroundTarget.
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//
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std::vector<unsigned> OrigLiveIn(LayoutSucc->livein_begin(),
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LayoutSucc->livein_end());
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std::vector<unsigned> NewLiveIn(JumpAroundTarget->livein_begin(),
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JumpAroundTarget->livein_end());
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for (unsigned i = 0; i < OrigLiveIn.size(); ++i) {
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LayoutSucc->removeLiveIn(OrigLiveIn[i]);
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}
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for (unsigned i = 0; i < NewLiveIn.size(); ++i) {
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LayoutSucc->addLiveIn(NewLiveIn[i]);
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}
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}
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}
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}
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}
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}
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}
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return true;
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}
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}
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//===----------------------------------------------------------------------===//
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// Public Constructor Functions
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//===----------------------------------------------------------------------===//
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FunctionPass *llvm::createHexagonCFGOptimizer(HexagonTargetMachine &TM) {
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return new HexagonCFGOptimizer(TM);
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}
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