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C++ Code::resetReachability方法代码示例

本文整理汇总了C++中Code::resetReachability方法的典型用法代码示例。如果您正苦于以下问题:C++ Code::resetReachability方法的具体用法?C++ Code::resetReachability怎么用?C++ Code::resetReachability使用的例子?那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在Code的用法示例。


在下文中一共展示了Code::resetReachability方法的2个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的C++代码示例。

示例1: prepareForGeneration

void prepareForGeneration(Code& code)
{
    TimingScope timingScope("Air::prepareForGeneration");
    
    // We don't expect the incoming code to have predecessors computed.
    code.resetReachability();
    
    if (shouldValidateIR())
        validate(code);

    // If we're doing super verbose dumping, the phase scope of any phase will already do a dump.
    if (shouldDumpIR() && !shouldDumpIRAtEachPhase()) {
        dataLog("Initial air:\n");
        dataLog(code);
    }

    // This is where we run our optimizations and transformations.
    // FIXME: Add Air optimizations.
    // https://bugs.webkit.org/show_bug.cgi?id=150456
    
    eliminateDeadCode(code);

    // Register allocation for all the Tmps that do not have a corresponding machine register.
    // After this phase, every Tmp has a reg.
    //
    // For debugging, you can use spillEverything() to put everything to the stack between each Inst.
    if (Options::airSpillsEverything())
        spillEverything(code);
    else
        iteratedRegisterCoalescing(code);

    // Prior to this point the prologue and epilogue is implicit. This makes it explicit. It also
    // does things like identify which callee-saves we're using and saves them.
    handleCalleeSaves(code);

    // This turns all Stack and CallArg Args into Addr args that use the frame pointer. It does
    // this by first-fit allocating stack slots. It should be pretty darn close to optimal, so we
    // shouldn't have to worry about this very much.
    allocateStack(code);

    // If we coalesced moves then we can unbreak critical edges. This is the main reason for this
    // phase.
    simplifyCFG(code);

    // This sorts the basic blocks in Code to achieve an ordering that maximizes the likelihood that a high
    // frequency successor is also the fall-through target.
    optimizeBlockOrder(code);

    // Attempt to remove false dependencies between instructions created by partial register changes.
    // This must be executed as late as possible as it depends on the instructions order and register use.
    fixPartialRegisterStalls(code);

    // This is needed to satisfy a requirement of B3::StackmapValue.
    reportUsedRegisters(code);

    if (shouldValidateIR())
        validate(code);

    // Do a final dump of Air. Note that we have to do this even if we are doing per-phase dumping,
    // since the final generation is not a phase.
    if (shouldDumpIR()) {
        dataLog("Air after ", code.lastPhaseName(), ", before generation:\n");
        dataLog(code);
    }
}
开发者ID:srinivas-kakarla,项目名称:WebKitForWayland,代码行数:65,代码来源:AirGenerate.cpp

示例2: simplifyCFG


//.........这里部分代码省略.........
                for (BasicBlock* block : code) {
                    for (BasicBlock* successor : block->successorBlocks())
                        RELEASE_ASSERT(successor->containsPredecessor(block));
                }
            }

            // We don't care about blocks that don't have successors.
            if (!block->numSuccessors())
                continue;

            // First check if any of the successors of this block can be forwarded over.
            for (BasicBlock*& successor : block->successorBlocks()) {
                if (successor != block
                    && successor->size() == 1
                    && successor->last().opcode == Jump) {
                    BasicBlock* newSuccessor = successor->successorBlock(0);
                    if (newSuccessor != successor) {
                        if (verbose) {
                            dataLog(
                                "Replacing ", pointerDump(block), "->", pointerDump(successor),
                                " with ", pointerDump(block), "->", pointerDump(newSuccessor), "\n");
                        }
                        // Note that we do not do replacePredecessor() because the block we're
                        // skipping will still have newSuccessor as its successor.
                        newSuccessor->addPredecessor(block);
                        successor = newSuccessor;
                        changed = true;
                    }
                }
            }

            // Now check if the block's terminal can be replaced with a jump.
            if (block->numSuccessors() > 1) {
                // The terminal must not have weird effects.
                if (!block->last().hasArgEffects()
                    && !block->last().hasNonArgNonControlEffects()) {
                    // All of the successors must be the same.
                    bool allSame = true;
                    BasicBlock* firstSuccessor = block->successorBlock(0);
                    for (unsigned i = 1; i < block->numSuccessors(); ++i) {
                        if (block->successorBlock(i) != firstSuccessor) {
                            allSame = false;
                            break;
                        }
                    }
                    if (allSame) {
                        if (verbose)
                            dataLog("Changing ", pointerDump(block), "'s terminal to a Jump.\n");
                        block->last() = Inst(Jump, block->last().origin);
                        block->successors().resize(1);
                        block->successors()[0].frequency() = FrequencyClass::Normal;
                        changed = true;
                    }
                }
            }

            // Finally handle jumps to a block with one predecessor.
            if (block->numSuccessors() == 1) {
                BasicBlock* successor = block->successorBlock(0);
                if (successor != block && successor->numPredecessors() == 1) {
                    RELEASE_ASSERT(successor->predecessor(0) == block);

                    // We can merge the two blocks because the predecessor only jumps to the successor
                    // and the successor is only reachable from the predecessor.

                    // Remove the terminal.
                    Value* origin = block->insts().takeLast().origin;

                    // Append the full contents of the successor to the predecessor.
                    block->insts().reserveCapacity(block->size() + successor->size());
                    for (Inst& inst : *successor)
                        block->appendInst(WTFMove(inst));

                    // Make sure that our successors are the successor's successors.
                    block->successors() = WTFMove(successor->successors());

                    // Make sure that the successor has nothing left in it except an oops.
                    successor->resize(1);
                    successor->last() = Inst(Oops, origin);
                    successor->successors().clear();

                    // Ensure that the predecessors of block's new successors know what's up.
                    for (BasicBlock* newSuccessor : block->successorBlocks())
                        newSuccessor->replacePredecessor(successor, block);

                    if (verbose)
                        dataLog("Merged ", pointerDump(block), "->", pointerDump(successor), "\n");
                    changed = true;
                }
            }
        }

        if (!changed)
            break;
        result = true;
        code.resetReachability();
    }

    return result;
}
开发者ID:teamfx,项目名称:openjfx-9-dev-rt,代码行数:101,代码来源:AirSimplifyCFG.cpp


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