Move GrOpsTask to gpu/ops and the the skgpu::v1 namespace

Bug: skia:11837
Change-Id: I9ee6343b5144b02e8f455df0ea01b8199a8f14e1
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/440837
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
diff --git a/src/gpu/ops/OpsTask.cpp b/src/gpu/ops/OpsTask.cpp
new file mode 100644
index 0000000..ab5c7cb
--- /dev/null
+++ b/src/gpu/ops/OpsTask.cpp
@@ -0,0 +1,1079 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "src/gpu/ops/OpsTask.h"
+
+#include "include/gpu/GrRecordingContext.h"
+#include "src/core/SkRectPriv.h"
+#include "src/core/SkScopeExit.h"
+#include "src/core/SkTraceEvent.h"
+#include "src/gpu/GrAttachment.h"
+#include "src/gpu/GrAuditTrail.h"
+#include "src/gpu/GrCaps.h"
+#include "src/gpu/GrGpu.h"
+#include "src/gpu/GrMemoryPool.h"
+#include "src/gpu/GrOpFlushState.h"
+#include "src/gpu/GrOpsRenderPass.h"
+#include "src/gpu/GrRecordingContextPriv.h"
+#include "src/gpu/GrRenderTarget.h"
+#include "src/gpu/GrResourceAllocator.h"
+#include "src/gpu/GrResourceProvider.h"
+#include "src/gpu/GrTexture.h"
+#include "src/gpu/geometry/GrRect.h"
+#include "src/gpu/ops/GrClearOp.h"
+
+////////////////////////////////////////////////////////////////////////////////
+
+namespace {
+
+// Experimentally we have found that most combining occurs within the first 10 comparisons.
+static const int kMaxOpMergeDistance = 10;
+static const int kMaxOpChainDistance = 10;
+
+////////////////////////////////////////////////////////////////////////////////
+
+inline bool can_reorder(const SkRect& a, const SkRect& b) { return !GrRectsOverlap(a, b); }
+
+GrOpsRenderPass* create_render_pass(GrGpu* gpu,
+                                    GrRenderTarget* rt,
+                                    bool useMSAASurface,
+                                    GrAttachment* stencil,
+                                    GrSurfaceOrigin origin,
+                                    const SkIRect& bounds,
+                                    GrLoadOp colorLoadOp,
+                                    const std::array<float, 4>& loadClearColor,
+                                    GrLoadOp stencilLoadOp,
+                                    GrStoreOp stencilStoreOp,
+                                    const SkTArray<GrSurfaceProxy*, true>& sampledProxies,
+                                    GrXferBarrierFlags renderPassXferBarriers) {
+    const GrOpsRenderPass::LoadAndStoreInfo kColorLoadStoreInfo {
+        colorLoadOp,
+        GrStoreOp::kStore,
+        loadClearColor
+    };
+
+    // TODO:
+    // We would like to (at this level) only ever clear & discard. We would need
+    // to stop splitting up higher level OpsTasks for copyOps to achieve that.
+    // Note: we would still need SB loads and stores but they would happen at a
+    // lower level (inside the VK command buffer).
+    const GrOpsRenderPass::StencilLoadAndStoreInfo stencilLoadAndStoreInfo {
+        stencilLoadOp,
+        stencilStoreOp,
+    };
+
+    return gpu->getOpsRenderPass(rt, useMSAASurface, stencil, origin, bounds, kColorLoadStoreInfo,
+                                 stencilLoadAndStoreInfo, sampledProxies, renderPassXferBarriers);
+}
+
+} // anonymous namespace
+
+////////////////////////////////////////////////////////////////////////////////
+
+namespace skgpu::v1 {
+
+inline OpsTask::OpChain::List::List(GrOp::Owner op)
+        : fHead(std::move(op)), fTail(fHead.get()) {
+    this->validate();
+}
+
+inline OpsTask::OpChain::List::List(List&& that) { *this = std::move(that); }
+
+inline OpsTask::OpChain::List& OpsTask::OpChain::List::operator=(List&& that) {
+    fHead = std::move(that.fHead);
+    fTail = that.fTail;
+    that.fTail = nullptr;
+    this->validate();
+    return *this;
+}
+
+inline GrOp::Owner OpsTask::OpChain::List::popHead() {
+    SkASSERT(fHead);
+    auto temp = fHead->cutChain();
+    std::swap(temp, fHead);
+    if (!fHead) {
+        SkASSERT(fTail == temp.get());
+        fTail = nullptr;
+    }
+    return temp;
+}
+
+inline GrOp::Owner OpsTask::OpChain::List::removeOp(GrOp* op) {
+#ifdef SK_DEBUG
+    auto head = op;
+    while (head->prevInChain()) { head = head->prevInChain(); }
+    SkASSERT(head == fHead.get());
+#endif
+    auto prev = op->prevInChain();
+    if (!prev) {
+        SkASSERT(op == fHead.get());
+        return this->popHead();
+    }
+    auto temp = prev->cutChain();
+    if (auto next = temp->cutChain()) {
+        prev->chainConcat(std::move(next));
+    } else {
+        SkASSERT(fTail == op);
+        fTail = prev;
+    }
+    this->validate();
+    return temp;
+}
+
+inline void OpsTask::OpChain::List::pushHead(GrOp::Owner op) {
+    SkASSERT(op);
+    SkASSERT(op->isChainHead());
+    SkASSERT(op->isChainTail());
+    if (fHead) {
+        op->chainConcat(std::move(fHead));
+        fHead = std::move(op);
+    } else {
+        fHead = std::move(op);
+        fTail = fHead.get();
+    }
+}
+
+inline void OpsTask::OpChain::List::pushTail(GrOp::Owner op) {
+    SkASSERT(op->isChainTail());
+    fTail->chainConcat(std::move(op));
+    fTail = fTail->nextInChain();
+}
+
+inline void OpsTask::OpChain::List::validate() const {
+#ifdef SK_DEBUG
+    if (fHead) {
+        SkASSERT(fTail);
+        fHead->validateChain(fTail);
+    }
+#endif
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+OpsTask::OpChain::OpChain(GrOp::Owner op, GrProcessorSet::Analysis processorAnalysis,
+                          GrAppliedClip* appliedClip, const GrDstProxyView* dstProxyView)
+        : fList{std::move(op)}
+        , fProcessorAnalysis(processorAnalysis)
+        , fAppliedClip(appliedClip) {
+    if (fProcessorAnalysis.requiresDstTexture()) {
+        SkASSERT(dstProxyView && dstProxyView->proxy());
+        fDstProxyView = *dstProxyView;
+    }
+    fBounds = fList.head()->bounds();
+}
+
+void OpsTask::OpChain::visitProxies(const GrVisitProxyFunc& func) const {
+    if (fList.empty()) {
+        return;
+    }
+    for (const auto& op : GrOp::ChainRange<>(fList.head())) {
+        op.visitProxies(func);
+    }
+    if (fDstProxyView.proxy()) {
+        func(fDstProxyView.proxy(), GrMipmapped::kNo);
+    }
+    if (fAppliedClip) {
+        fAppliedClip->visitProxies(func);
+    }
+}
+
+void OpsTask::OpChain::deleteOps() {
+    while (!fList.empty()) {
+        // Since the value goes out of scope immediately, the GrOp::Owner deletes the op.
+        fList.popHead();
+    }
+}
+
+// Concatenates two op chains and attempts to merge ops across the chains. Assumes that we know that
+// the two chains are chainable. Returns the new chain.
+OpsTask::OpChain::List OpsTask::OpChain::DoConcat(List chainA, List chainB, const GrCaps& caps,
+                                                  SkArenaAlloc* opsTaskArena,
+                                                  GrAuditTrail* auditTrail) {
+    // We process ops in chain b from head to tail. We attempt to merge with nodes in a, starting
+    // at chain a's tail and working toward the head. We produce one of the following outcomes:
+    // 1) b's head is merged into an op in a.
+    // 2) An op from chain a is merged into b's head. (In this case b's head gets processed again.)
+    // 3) b's head is popped from chain a and added at the tail of a.
+    // After result 3 we don't want to attempt to merge the next head of b with the new tail of a,
+    // as we assume merges were already attempted when chain b was created. So we keep track of the
+    // original tail of a and start our iteration of a there. We also track the bounds of the nodes
+    // appended to chain a that will be skipped for bounds testing. If the original tail of a is
+    // merged into an op in b (case 2) then we advance the "original tail" towards the head of a.
+    GrOp* origATail = chainA.tail();
+    SkRect skipBounds = SkRectPriv::MakeLargestInverted();
+    do {
+        int numMergeChecks = 0;
+        bool merged = false;
+        bool noSkip = (origATail == chainA.tail());
+        SkASSERT(noSkip == (skipBounds == SkRectPriv::MakeLargestInverted()));
+        bool canBackwardMerge = noSkip || can_reorder(chainB.head()->bounds(), skipBounds);
+        SkRect forwardMergeBounds = skipBounds;
+        GrOp* a = origATail;
+        while (a) {
+            bool canForwardMerge =
+                    (a == chainA.tail()) || can_reorder(a->bounds(), forwardMergeBounds);
+            if (canForwardMerge || canBackwardMerge) {
+                auto result = a->combineIfPossible(chainB.head(), opsTaskArena, caps);
+                SkASSERT(result != GrOp::CombineResult::kCannotCombine);
+                merged = (result == GrOp::CombineResult::kMerged);
+                GrOP_INFO("\t\t: (%s opID: %u) -> Combining with (%s, opID: %u)\n",
+                          chainB.head()->name(), chainB.head()->uniqueID(), a->name(),
+                          a->uniqueID());
+            }
+            if (merged) {
+                GR_AUDIT_TRAIL_OPS_RESULT_COMBINED(auditTrail, a, chainB.head());
+                if (canBackwardMerge) {
+                    // The GrOp::Owner releases the op.
+                    chainB.popHead();
+                } else {
+                    // We merged the contents of b's head into a. We will replace b's head with a in
+                    // chain b.
+                    SkASSERT(canForwardMerge);
+                    if (a == origATail) {
+                        origATail = a->prevInChain();
+                    }
+                    GrOp::Owner detachedA = chainA.removeOp(a);
+                    // The GrOp::Owner releases the op.
+                    chainB.popHead();
+                    chainB.pushHead(std::move(detachedA));
+                    if (chainA.empty()) {
+                        // We merged all the nodes in chain a to chain b.
+                        return chainB;
+                    }
+                }
+                break;
+            } else {
+                if (++numMergeChecks == kMaxOpMergeDistance) {
+                    break;
+                }
+                forwardMergeBounds.joinNonEmptyArg(a->bounds());
+                canBackwardMerge =
+                        canBackwardMerge && can_reorder(chainB.head()->bounds(), a->bounds());
+                a = a->prevInChain();
+            }
+        }
+        // If we weren't able to merge b's head then pop b's head from chain b and make it the new
+        // tail of a.
+        if (!merged) {
+            chainA.pushTail(chainB.popHead());
+            skipBounds.joinNonEmptyArg(chainA.tail()->bounds());
+        }
+    } while (!chainB.empty());
+    return chainA;
+}
+
+// Attempts to concatenate the given chain onto our own and merge ops across the chains. Returns
+// whether the operation succeeded. On success, the provided list will be returned empty.
+bool OpsTask::OpChain::tryConcat(
+        List* list, GrProcessorSet::Analysis processorAnalysis, const GrDstProxyView& dstProxyView,
+        const GrAppliedClip* appliedClip, const SkRect& bounds, const GrCaps& caps,
+        SkArenaAlloc* opsTaskArena, GrAuditTrail* auditTrail) {
+    SkASSERT(!fList.empty());
+    SkASSERT(!list->empty());
+    SkASSERT(fProcessorAnalysis.requiresDstTexture() == SkToBool(fDstProxyView.proxy()));
+    SkASSERT(processorAnalysis.requiresDstTexture() == SkToBool(dstProxyView.proxy()));
+    // All returns use explicit tuple constructor rather than {a, b} to work around old GCC bug.
+    if (fList.head()->classID() != list->head()->classID() ||
+        SkToBool(fAppliedClip) != SkToBool(appliedClip) ||
+        (fAppliedClip && *fAppliedClip != *appliedClip) ||
+        (fProcessorAnalysis.requiresNonOverlappingDraws() !=
+                processorAnalysis.requiresNonOverlappingDraws()) ||
+        (fProcessorAnalysis.requiresNonOverlappingDraws() &&
+                // Non-overlaping draws are only required when Ganesh will either insert a barrier,
+                // or read back a new dst texture between draws. In either case, we can neither
+                // chain nor combine overlapping Ops.
+                GrRectsTouchOrOverlap(fBounds, bounds)) ||
+        (fProcessorAnalysis.requiresDstTexture() != processorAnalysis.requiresDstTexture()) ||
+        (fProcessorAnalysis.requiresDstTexture() && fDstProxyView != dstProxyView)) {
+        return false;
+    }
+
+    SkDEBUGCODE(bool first = true;)
+    do {
+        switch (fList.tail()->combineIfPossible(list->head(), opsTaskArena, caps))
+        {
+            case GrOp::CombineResult::kCannotCombine:
+                // If an op supports chaining then it is required that chaining is transitive and
+                // that if any two ops in two different chains can merge then the two chains
+                // may also be chained together. Thus, we should only hit this on the first
+                // iteration.
+                SkASSERT(first);
+                return false;
+            case GrOp::CombineResult::kMayChain:
+                fList = DoConcat(std::move(fList), std::exchange(*list, List()), caps, opsTaskArena,
+                                 auditTrail);
+                // The above exchange cleared out 'list'. The list needs to be empty now for the
+                // loop to terminate.
+                SkASSERT(list->empty());
+                break;
+            case GrOp::CombineResult::kMerged: {
+                GrOP_INFO("\t\t: (%s opID: %u) -> Combining with (%s, opID: %u)\n",
+                          list->tail()->name(), list->tail()->uniqueID(), list->head()->name(),
+                          list->head()->uniqueID());
+                GR_AUDIT_TRAIL_OPS_RESULT_COMBINED(auditTrail, fList.tail(), list->head());
+                // The GrOp::Owner releases the op.
+                list->popHead();
+                break;
+            }
+        }
+        SkDEBUGCODE(first = false);
+    } while (!list->empty());
+
+    // The new ops were successfully merged and/or chained onto our own.
+    fBounds.joinPossiblyEmptyRect(bounds);
+    return true;
+}
+
+bool OpsTask::OpChain::prependChain(OpChain* that, const GrCaps& caps, SkArenaAlloc* opsTaskArena,
+                                    GrAuditTrail* auditTrail) {
+    if (!that->tryConcat(&fList, fProcessorAnalysis, fDstProxyView, fAppliedClip, fBounds, caps,
+                         opsTaskArena, auditTrail)) {
+        this->validate();
+        // append failed
+        return false;
+    }
+
+    // 'that' owns the combined chain. Move it into 'this'.
+    SkASSERT(fList.empty());
+    fList = std::move(that->fList);
+    fBounds = that->fBounds;
+
+    that->fDstProxyView.setProxyView({});
+    if (that->fAppliedClip && that->fAppliedClip->hasCoverageFragmentProcessor()) {
+        // Obliterates the processor.
+        that->fAppliedClip->detachCoverageFragmentProcessor();
+    }
+    this->validate();
+    return true;
+}
+
+GrOp::Owner OpsTask::OpChain::appendOp(
+        GrOp::Owner op, GrProcessorSet::Analysis processorAnalysis,
+        const GrDstProxyView* dstProxyView, const GrAppliedClip* appliedClip, const GrCaps& caps,
+        SkArenaAlloc* opsTaskArena, GrAuditTrail* auditTrail) {
+    const GrDstProxyView noDstProxyView;
+    if (!dstProxyView) {
+        dstProxyView = &noDstProxyView;
+    }
+    SkASSERT(op->isChainHead() && op->isChainTail());
+    SkRect opBounds = op->bounds();
+    List chain(std::move(op));
+    if (!this->tryConcat(&chain, processorAnalysis, *dstProxyView, appliedClip, opBounds, caps,
+                         opsTaskArena, auditTrail)) {
+        // append failed, give the op back to the caller.
+        this->validate();
+        return chain.popHead();
+    }
+
+    SkASSERT(chain.empty());
+    this->validate();
+    return nullptr;
+}
+
+inline void OpsTask::OpChain::validate() const {
+#ifdef SK_DEBUG
+    fList.validate();
+    for (const auto& op : GrOp::ChainRange<>(fList.head())) {
+        // Not using SkRect::contains because we allow empty rects.
+        SkASSERT(fBounds.fLeft <= op.bounds().fLeft && fBounds.fTop <= op.bounds().fTop &&
+                 fBounds.fRight >= op.bounds().fRight && fBounds.fBottom >= op.bounds().fBottom);
+    }
+#endif
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+OpsTask::OpsTask(GrDrawingManager* drawingMgr,
+                 GrSurfaceProxyView view,
+                 GrAuditTrail* auditTrail,
+                 sk_sp<GrArenas> arenas)
+        : GrRenderTask()
+        , fAuditTrail(auditTrail)
+        , fUsesMSAASurface(view.asRenderTargetProxy()->numSamples() > 1)
+        , fTargetSwizzle(view.swizzle())
+        , fTargetOrigin(view.origin())
+        , fArenas{std::move(arenas)}
+          SkDEBUGCODE(, fNumClips(0)) {
+    this->addTarget(drawingMgr, view.detachProxy());
+}
+
+void OpsTask::deleteOps() {
+    for (auto& chain : fOpChains) {
+        chain.deleteOps();
+    }
+    fOpChains.reset();
+}
+
+OpsTask::~OpsTask() {
+    this->deleteOps();
+}
+
+void OpsTask::addOp(GrDrawingManager* drawingMgr, GrOp::Owner op,
+                    GrTextureResolveManager textureResolveManager, const GrCaps& caps) {
+    auto addDependency = [&](GrSurfaceProxy* p, GrMipmapped mipmapped) {
+        this->addDependency(drawingMgr, p, mipmapped, textureResolveManager, caps);
+    };
+
+    op->visitProxies(addDependency);
+
+    this->recordOp(std::move(op), false/*usesMSAA*/, GrProcessorSet::EmptySetAnalysis(), nullptr,
+                   nullptr, caps);
+}
+
+void OpsTask::addDrawOp(GrDrawingManager* drawingMgr, GrOp::Owner op, bool usesMSAA,
+                        const GrProcessorSet::Analysis& processorAnalysis, GrAppliedClip&& clip,
+                        const GrDstProxyView& dstProxyView,
+                        GrTextureResolveManager textureResolveManager, const GrCaps& caps) {
+    auto addDependency = [&](GrSurfaceProxy* p, GrMipmapped mipmapped) {
+        this->addSampledTexture(p);
+        this->addDependency(drawingMgr, p, mipmapped, textureResolveManager, caps);
+    };
+
+    op->visitProxies(addDependency);
+    clip.visitProxies(addDependency);
+    if (dstProxyView.proxy()) {
+        if (!(dstProxyView.dstSampleFlags() & GrDstSampleFlags::kAsInputAttachment)) {
+            this->addSampledTexture(dstProxyView.proxy());
+        }
+        if (dstProxyView.dstSampleFlags() & GrDstSampleFlags::kRequiresTextureBarrier) {
+            fRenderPassXferBarriers |= GrXferBarrierFlags::kTexture;
+        }
+        addDependency(dstProxyView.proxy(), GrMipmapped::kNo);
+        SkASSERT(!(dstProxyView.dstSampleFlags() & GrDstSampleFlags::kAsInputAttachment) ||
+                 dstProxyView.offset().isZero());
+    }
+
+    if (processorAnalysis.usesNonCoherentHWBlending()) {
+        fRenderPassXferBarriers |= GrXferBarrierFlags::kBlend;
+    }
+
+    this->recordOp(std::move(op), usesMSAA, processorAnalysis, clip.doesClip() ? &clip : nullptr,
+                   &dstProxyView, caps);
+}
+
+void OpsTask::endFlush(GrDrawingManager* drawingMgr) {
+    fLastClipStackGenID = SK_InvalidUniqueID;
+    this->deleteOps();
+
+    fDeferredProxies.reset();
+    fSampledProxies.reset();
+    fAuditTrail = nullptr;
+
+    GrRenderTask::endFlush(drawingMgr);
+}
+
+void OpsTask::onPrePrepare(GrRecordingContext* context) {
+    SkASSERT(this->isClosed());
+    // TODO: remove the check for discard here once reduced op splitting is turned on. Currently we
+    // can end up with OpsTasks that only have a discard load op and no ops. For vulkan validation
+    // we need to keep that discard and not drop it. Once we have reduce op list splitting enabled
+    // we shouldn't end up with OpsTasks with only discard.
+    if (this->isColorNoOp() ||
+        (fClippedContentBounds.isEmpty() && fColorLoadOp != GrLoadOp::kDiscard)) {
+        return;
+    }
+    TRACE_EVENT0("skia.gpu", TRACE_FUNC);
+
+    GrSurfaceProxyView dstView(sk_ref_sp(this->target(0)), fTargetOrigin, fTargetSwizzle);
+    for (const auto& chain : fOpChains) {
+        if (chain.shouldExecute()) {
+            chain.head()->prePrepare(context,
+                                     dstView,
+                                     chain.appliedClip(),
+                                     chain.dstProxyView(),
+                                     fRenderPassXferBarriers,
+                                     fColorLoadOp);
+        }
+    }
+}
+
+void OpsTask::onPrepare(GrOpFlushState* flushState) {
+    SkASSERT(this->target(0)->peekRenderTarget());
+    SkASSERT(this->isClosed());
+    // TODO: remove the check for discard here once reduced op splitting is turned on. Currently we
+    // can end up with OpsTasks that only have a discard load op and no ops. For vulkan validation
+    // we need to keep that discard and not drop it. Once we have reduce op list splitting enabled
+    // we shouldn't end up with OpsTasks with only discard.
+    if (this->isColorNoOp() ||
+        (fClippedContentBounds.isEmpty() && fColorLoadOp != GrLoadOp::kDiscard)) {
+        return;
+    }
+    TRACE_EVENT0("skia.gpu", TRACE_FUNC);
+
+    flushState->setSampledProxyArray(&fSampledProxies);
+    GrSurfaceProxyView dstView(sk_ref_sp(this->target(0)), fTargetOrigin, fTargetSwizzle);
+    // Loop over the ops that haven't yet been prepared.
+    for (const auto& chain : fOpChains) {
+        if (chain.shouldExecute()) {
+#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
+            TRACE_EVENT0("skia.gpu", chain.head()->name());
+#endif
+            GrOpFlushState::OpArgs opArgs(chain.head(),
+                                          dstView,
+                                          fUsesMSAASurface,
+                                          chain.appliedClip(),
+                                          chain.dstProxyView(),
+                                          fRenderPassXferBarriers,
+                                          fColorLoadOp);
+
+            flushState->setOpArgs(&opArgs);
+
+            // Temporary debugging helper: for debugging prePrepare w/o going through DDLs
+            // Delete once most of the GrOps have an onPrePrepare.
+            // chain.head()->prePrepare(flushState->gpu()->getContext(), &this->target(0),
+            //                          chain.appliedClip());
+
+            // GrOp::prePrepare may or may not have been called at this point
+            chain.head()->prepare(flushState);
+            flushState->setOpArgs(nullptr);
+        }
+    }
+    flushState->setSampledProxyArray(nullptr);
+}
+
+// TODO: this is where GrOp::renderTarget is used (which is fine since it
+// is at flush time). However, we need to store the RenderTargetProxy in the
+// Ops and instantiate them here.
+bool OpsTask::onExecute(GrOpFlushState* flushState) {
+    SkASSERT(this->numTargets() == 1);
+    GrRenderTargetProxy* proxy = this->target(0)->asRenderTargetProxy();
+    SkASSERT(proxy);
+    SK_AT_SCOPE_EXIT(proxy->clearArenas());
+
+    // TODO: remove the check for discard here once reduced op splitting is turned on. Currently we
+    // can end up with OpsTasks that only have a discard load op and no ops. For vulkan validation
+    // we need to keep that discard and not drop it. Once we have reduce op list splitting enabled
+    // we shouldn't end up with OpsTasks with only discard.
+    if (this->isColorNoOp() ||
+        (fClippedContentBounds.isEmpty() && fColorLoadOp != GrLoadOp::kDiscard)) {
+        return false;
+    }
+
+    TRACE_EVENT0("skia.gpu", TRACE_FUNC);
+
+    // Make sure load ops are not kClear if the GPU needs to use draws for clears
+    SkASSERT(fColorLoadOp != GrLoadOp::kClear ||
+             !flushState->gpu()->caps()->performColorClearsAsDraws());
+
+    const GrCaps& caps = *flushState->gpu()->caps();
+    GrRenderTarget* renderTarget = proxy->peekRenderTarget();
+    SkASSERT(renderTarget);
+
+    GrAttachment* stencil = nullptr;
+    if (proxy->needsStencil()) {
+        SkASSERT(proxy->canUseStencil(caps));
+        if (!flushState->resourceProvider()->attachStencilAttachment(renderTarget,
+                                                                     fUsesMSAASurface)) {
+            SkDebugf("WARNING: failed to attach a stencil buffer. Rendering will be skipped.\n");
+            return false;
+        }
+        stencil = renderTarget->getStencilAttachment(fUsesMSAASurface);
+    }
+
+    GrLoadOp stencilLoadOp;
+    switch (fInitialStencilContent) {
+        case StencilContent::kDontCare:
+            stencilLoadOp = GrLoadOp::kDiscard;
+            break;
+        case StencilContent::kUserBitsCleared:
+            SkASSERT(!caps.performStencilClearsAsDraws());
+            SkASSERT(stencil);
+            if (caps.discardStencilValuesAfterRenderPass()) {
+                // Always clear the stencil if it is being discarded after render passes. This is
+                // also an optimization because we are on a tiler and it avoids loading the values
+                // from memory.
+                stencilLoadOp = GrLoadOp::kClear;
+                break;
+            }
+            if (!stencil->hasPerformedInitialClear()) {
+                stencilLoadOp = GrLoadOp::kClear;
+                stencil->markHasPerformedInitialClear();
+                break;
+            }
+            // SurfaceDrawContexts are required to leave the user stencil bits in a cleared state
+            // once finished, meaning the stencil values will always remain cleared after the
+            // initial clear. Just fall through to reloading the existing (cleared) stencil values
+            // from memory.
+            [[fallthrough]];
+        case StencilContent::kPreserved:
+            SkASSERT(stencil);
+            stencilLoadOp = GrLoadOp::kLoad;
+            break;
+    }
+
+    // NOTE: If fMustPreserveStencil is set, then we are executing a surfaceDrawContext that split
+    // its opsTask.
+    //
+    // FIXME: We don't currently flag render passes that don't use stencil at all. In that case
+    // their store op might be "discard", and we currently make the assumption that a discard will
+    // not invalidate what's already in main memory. This is probably ok for now, but certainly
+    // something we want to address soon.
+    GrStoreOp stencilStoreOp = (caps.discardStencilValuesAfterRenderPass() && !fMustPreserveStencil)
+            ? GrStoreOp::kDiscard
+            : GrStoreOp::kStore;
+
+    GrOpsRenderPass* renderPass = create_render_pass(flushState->gpu(),
+                                                     proxy->peekRenderTarget(),
+                                                     fUsesMSAASurface,
+                                                     stencil,
+                                                     fTargetOrigin,
+                                                     fClippedContentBounds,
+                                                     fColorLoadOp,
+                                                     fLoadClearColor,
+                                                     stencilLoadOp,
+                                                     stencilStoreOp,
+                                                     fSampledProxies,
+                                                     fRenderPassXferBarriers);
+
+    if (!renderPass) {
+        return false;
+    }
+    flushState->setOpsRenderPass(renderPass);
+    renderPass->begin();
+
+    GrSurfaceProxyView dstView(sk_ref_sp(this->target(0)), fTargetOrigin, fTargetSwizzle);
+
+    // Draw all the generated geometry.
+    for (const auto& chain : fOpChains) {
+        if (!chain.shouldExecute()) {
+            continue;
+        }
+#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
+        TRACE_EVENT0("skia.gpu", chain.head()->name());
+#endif
+
+        GrOpFlushState::OpArgs opArgs(chain.head(),
+                                      dstView,
+                                      fUsesMSAASurface,
+                                      chain.appliedClip(),
+                                      chain.dstProxyView(),
+                                      fRenderPassXferBarriers,
+                                      fColorLoadOp);
+
+        flushState->setOpArgs(&opArgs);
+        chain.head()->execute(flushState, chain.bounds());
+        flushState->setOpArgs(nullptr);
+    }
+
+    renderPass->end();
+    flushState->gpu()->submit(renderPass);
+    flushState->setOpsRenderPass(nullptr);
+
+    return true;
+}
+
+void OpsTask::setColorLoadOp(GrLoadOp op, std::array<float, 4> color) {
+    fColorLoadOp = op;
+    fLoadClearColor = color;
+    if (GrLoadOp::kClear == fColorLoadOp) {
+        GrSurfaceProxy* proxy = this->target(0);
+        SkASSERT(proxy);
+        fTotalBounds = proxy->backingStoreBoundsRect();
+    }
+}
+
+void OpsTask::reset() {
+    fDeferredProxies.reset();
+    fSampledProxies.reset();
+    fClippedContentBounds = SkIRect::MakeEmpty();
+    fTotalBounds = SkRect::MakeEmpty();
+    this->deleteOps();
+    fRenderPassXferBarriers = GrXferBarrierFlags::kNone;
+}
+
+bool OpsTask::canMerge(const OpsTask* opsTask) const {
+    return this->target(0) == opsTask->target(0) &&
+           fArenas == opsTask->fArenas &&
+           !opsTask->fCannotMergeBackward;
+}
+
+int OpsTask::mergeFrom(SkSpan<const sk_sp<GrRenderTask>> tasks) {
+    int mergedCount = 0;
+    for (const sk_sp<GrRenderTask>& task : tasks) {
+        auto opsTask = task->asOpsTask();
+        if (!opsTask || !this->canMerge(opsTask)) {
+            break;
+        }
+        SkASSERT(fTargetSwizzle == opsTask->fTargetSwizzle);
+        SkASSERT(fTargetOrigin == opsTask->fTargetOrigin);
+        if (GrLoadOp::kClear == opsTask->fColorLoadOp) {
+            // TODO(11903): Go back to actually dropping ops tasks when we are merged with
+            // color clear.
+            return 0;
+        }
+        mergedCount += 1;
+    }
+    if (0 == mergedCount) {
+        return 0;
+    }
+
+    SkSpan<const sk_sp<OpsTask>> mergingNodes(
+            reinterpret_cast<const sk_sp<OpsTask>*>(tasks.data()), SkToSizeT(mergedCount));
+    int addlDeferredProxyCount = 0;
+    int addlProxyCount = 0;
+    int addlOpChainCount = 0;
+    for (const auto& toMerge : mergingNodes) {
+        addlDeferredProxyCount += toMerge->fDeferredProxies.count();
+        addlProxyCount += toMerge->fSampledProxies.count();
+        addlOpChainCount += toMerge->fOpChains.count();
+        fClippedContentBounds.join(toMerge->fClippedContentBounds);
+        fTotalBounds.join(toMerge->fTotalBounds);
+        fRenderPassXferBarriers |= toMerge->fRenderPassXferBarriers;
+        if (fInitialStencilContent == StencilContent::kDontCare) {
+            // Propogate the first stencil content that isn't kDontCare.
+            //
+            // Once the stencil has any kind of initial content that isn't kDontCare, then the
+            // inital contents of subsequent opsTasks that get merged in don't matter.
+            //
+            // (This works because the opsTask all target the same render target and are in
+            // painter's order. kPreserved obviously happens automatically with a merge, and kClear
+            // is also automatic because the contract is for ops to leave the stencil buffer in a
+            // cleared state when finished.)
+            fInitialStencilContent = toMerge->fInitialStencilContent;
+        }
+        fUsesMSAASurface |= toMerge->fUsesMSAASurface;
+        SkDEBUGCODE(fNumClips += toMerge->fNumClips);
+    }
+
+    fLastClipStackGenID = SK_InvalidUniqueID;
+    fDeferredProxies.reserve_back(addlDeferredProxyCount);
+    fSampledProxies.reserve_back(addlProxyCount);
+    fOpChains.reserve_back(addlOpChainCount);
+    for (const auto& toMerge : mergingNodes) {
+        for (GrRenderTask* renderTask : toMerge->dependents()) {
+            renderTask->replaceDependency(toMerge.get(), this);
+        }
+        for (GrRenderTask* renderTask : toMerge->dependencies()) {
+            renderTask->replaceDependent(toMerge.get(), this);
+        }
+        fDeferredProxies.move_back_n(toMerge->fDeferredProxies.count(),
+                                     toMerge->fDeferredProxies.data());
+        fSampledProxies.move_back_n(toMerge->fSampledProxies.count(),
+                                    toMerge->fSampledProxies.data());
+        fOpChains.move_back_n(toMerge->fOpChains.count(),
+                              toMerge->fOpChains.data());
+        toMerge->fDeferredProxies.reset();
+        toMerge->fSampledProxies.reset();
+        toMerge->fOpChains.reset();
+    }
+    fMustPreserveStencil = mergingNodes.back()->fMustPreserveStencil;
+    return mergedCount;
+}
+
+bool OpsTask::resetForFullscreenClear(CanDiscardPreviousOps canDiscardPreviousOps) {
+    if (CanDiscardPreviousOps::kYes == canDiscardPreviousOps || this->isEmpty()) {
+        this->deleteOps();
+        fDeferredProxies.reset();
+        fSampledProxies.reset();
+
+        // If the opsTask is using a render target which wraps a vulkan command buffer, we can't do
+        // a clear load since we cannot change the render pass that we are using. Thus we fall back
+        // to making a clear op in this case.
+        return !this->target(0)->asRenderTargetProxy()->wrapsVkSecondaryCB();
+    }
+
+    // Could not empty the task, so an op must be added to handle the clear
+    return false;
+}
+
+void OpsTask::discard() {
+    // Discard calls to in-progress opsTasks are ignored. Calls at the start update the
+    // opsTasks' color & stencil load ops.
+    if (this->isEmpty()) {
+        fColorLoadOp = GrLoadOp::kDiscard;
+        fInitialStencilContent = StencilContent::kDontCare;
+        fTotalBounds.setEmpty();
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+#if GR_TEST_UTILS
+void OpsTask::dump(const SkString& label,
+                   SkString indent,
+                   bool printDependencies,
+                   bool close) const {
+    GrRenderTask::dump(label, indent, printDependencies, false);
+
+    SkDebugf("%sfColorLoadOp: ", indent.c_str());
+    switch (fColorLoadOp) {
+        case GrLoadOp::kLoad:
+            SkDebugf("kLoad\n");
+            break;
+        case GrLoadOp::kClear:
+            SkDebugf("kClear {%g, %g, %g, %g}\n",
+                     fLoadClearColor[0],
+                     fLoadClearColor[1],
+                     fLoadClearColor[2],
+                     fLoadClearColor[3]);
+            break;
+        case GrLoadOp::kDiscard:
+            SkDebugf("kDiscard\n");
+            break;
+    }
+
+    SkDebugf("%sfInitialStencilContent: ", indent.c_str());
+    switch (fInitialStencilContent) {
+        case StencilContent::kDontCare:
+            SkDebugf("kDontCare\n");
+            break;
+        case StencilContent::kUserBitsCleared:
+            SkDebugf("kUserBitsCleared\n");
+            break;
+        case StencilContent::kPreserved:
+            SkDebugf("kPreserved\n");
+            break;
+    }
+
+    SkDebugf("%s%d ops:\n", indent.c_str(), fOpChains.count());
+    for (int i = 0; i < fOpChains.count(); ++i) {
+        SkDebugf("%s*******************************\n", indent.c_str());
+        if (!fOpChains[i].head()) {
+            SkDebugf("%s%d: <combined forward or failed instantiation>\n", indent.c_str(), i);
+        } else {
+            SkDebugf("%s%d: %s\n", indent.c_str(), i, fOpChains[i].head()->name());
+            SkRect bounds = fOpChains[i].bounds();
+            SkDebugf("%sClippedBounds: [L: %.2f, T: %.2f, R: %.2f, B: %.2f]\n",
+                     indent.c_str(),
+                     bounds.fLeft, bounds.fTop, bounds.fRight, bounds.fBottom);
+            for (const auto& op : GrOp::ChainRange<>(fOpChains[i].head())) {
+                SkString info = SkTabString(op.dumpInfo(), 1);
+                SkDebugf("%s%s\n", indent.c_str(), info.c_str());
+                bounds = op.bounds();
+                SkDebugf("%s\tClippedBounds: [L: %.2f, T: %.2f, R: %.2f, B: %.2f]\n",
+                         indent.c_str(),
+                         bounds.fLeft, bounds.fTop, bounds.fRight, bounds.fBottom);
+            }
+        }
+    }
+
+    if (close) {
+        SkDebugf("%s--------------------------------------------------------------\n\n",
+                 indent.c_str());
+    }
+}
+#endif
+
+#ifdef SK_DEBUG
+void OpsTask::visitProxies_debugOnly(const GrVisitProxyFunc& func) const {
+    auto textureFunc = [ func ] (GrSurfaceProxy* tex, GrMipmapped mipmapped) {
+        func(tex, mipmapped);
+    };
+
+    for (const OpChain& chain : fOpChains) {
+        chain.visitProxies(textureFunc);
+    }
+}
+
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+
+void OpsTask::onMakeSkippable() {
+    this->deleteOps();
+    fDeferredProxies.reset();
+    fColorLoadOp = GrLoadOp::kLoad;
+    SkASSERT(this->isColorNoOp());
+}
+
+bool OpsTask::onIsUsed(GrSurfaceProxy* proxyToCheck) const {
+    bool used = false;
+    for (GrSurfaceProxy* proxy : fSampledProxies) {
+        if (proxy == proxyToCheck) {
+            used = true;
+            break;
+        }
+    }
+#ifdef SK_DEBUG
+    bool usedSlow = false;
+    auto visit = [ proxyToCheck, &usedSlow ] (GrSurfaceProxy* p, GrMipmapped) {
+        if (p == proxyToCheck) {
+            usedSlow = true;
+        }
+    };
+    this->visitProxies_debugOnly(visit);
+    SkASSERT(used == usedSlow);
+#endif
+
+    return used;
+}
+
+void OpsTask::gatherProxyIntervals(GrResourceAllocator* alloc) const {
+    SkASSERT(this->isClosed());
+    if (this->isColorNoOp()) {
+        return;
+    }
+
+    for (int i = 0; i < fDeferredProxies.count(); ++i) {
+        SkASSERT(!fDeferredProxies[i]->isInstantiated());
+        // We give all the deferred proxies a write usage at the very start of flushing. This
+        // locks them out of being reused for the entire flush until they are read - and then
+        // they can be recycled. This is a bit unfortunate because a flush can proceed in waves
+        // with sub-flushes. The deferred proxies only need to be pinned from the start of
+        // the sub-flush in which they appear.
+        alloc->addInterval(fDeferredProxies[i], 0, 0, GrResourceAllocator::ActualUse::kNo);
+    }
+
+    GrSurfaceProxy* targetProxy = this->target(0);
+
+    // Add the interval for all the writes to this OpsTasks's target
+    if (fOpChains.count()) {
+        unsigned int cur = alloc->curOp();
+
+        alloc->addInterval(targetProxy, cur, cur + fOpChains.count() - 1,
+                           GrResourceAllocator::ActualUse::kYes);
+    } else {
+        // This can happen if there is a loadOp (e.g., a clear) but no other draws. In this case we
+        // still need to add an interval for the destination so we create a fake op# for
+        // the missing clear op.
+        alloc->addInterval(targetProxy, alloc->curOp(), alloc->curOp(),
+                           GrResourceAllocator::ActualUse::kYes);
+        alloc->incOps();
+    }
+
+    auto gather = [ alloc SkDEBUGCODE(, this) ] (GrSurfaceProxy* p, GrMipmapped) {
+        alloc->addInterval(p,
+                           alloc->curOp(),
+                           alloc->curOp(),
+                           GrResourceAllocator::ActualUse::kYes
+                           SkDEBUGCODE(, this->target(0) == p));
+    };
+    // TODO: visitProxies is expensive. Can we do this with fSampledProxies instead?
+    for (const OpChain& recordedOp : fOpChains) {
+        recordedOp.visitProxies(gather);
+
+        // Even though the op may have been (re)moved we still need to increment the op count to
+        // keep all the math consistent.
+        alloc->incOps();
+    }
+}
+
+void OpsTask::recordOp(
+        GrOp::Owner op, bool usesMSAA, GrProcessorSet::Analysis processorAnalysis,
+        GrAppliedClip* clip, const GrDstProxyView* dstProxyView, const GrCaps& caps) {
+    GrSurfaceProxy* proxy = this->target(0);
+#ifdef SK_DEBUG
+    op->validate();
+    SkASSERT(processorAnalysis.requiresDstTexture() == (dstProxyView && dstProxyView->proxy()));
+    SkASSERT(proxy);
+    // A closed OpsTask should never receive new/more ops
+    SkASSERT(!this->isClosed());
+    // Ensure we can support dynamic msaa if the caller is trying to trigger it.
+    if (proxy->asRenderTargetProxy()->numSamples() == 1 && usesMSAA) {
+        SkASSERT(caps.supportsDynamicMSAA(proxy->asRenderTargetProxy()));
+    }
+#endif
+
+    if (!op->bounds().isFinite()) {
+        return;
+    }
+
+    fUsesMSAASurface |= usesMSAA;
+
+    // Account for this op's bounds before we attempt to combine.
+    // NOTE: The caller should have already called "op->setClippedBounds()" by now, if applicable.
+    fTotalBounds.join(op->bounds());
+
+    // Check if there is an op we can combine with by linearly searching back until we either
+    // 1) check every op
+    // 2) intersect with something
+    // 3) find a 'blocker'
+    GR_AUDIT_TRAIL_ADD_OP(fAuditTrail, op.get(), proxy->uniqueID());
+    GrOP_INFO("opsTask: %d Recording (%s, opID: %u)\n"
+              "\tBounds [L: %.2f, T: %.2f R: %.2f B: %.2f]\n",
+               this->uniqueID(),
+               op->name(),
+               op->uniqueID(),
+               op->bounds().fLeft, op->bounds().fTop,
+               op->bounds().fRight, op->bounds().fBottom);
+    GrOP_INFO(SkTabString(op->dumpInfo(), 1).c_str());
+    GrOP_INFO("\tOutcome:\n");
+    int maxCandidates = std::min(kMaxOpChainDistance, fOpChains.count());
+    if (maxCandidates) {
+        int i = 0;
+        while (true) {
+            OpChain& candidate = fOpChains.fromBack(i);
+            op = candidate.appendOp(std::move(op), processorAnalysis, dstProxyView, clip, caps,
+                                    fArenas->arenaAlloc(), fAuditTrail);
+            if (!op) {
+                return;
+            }
+            // Stop going backwards if we would cause a painter's order violation.
+            if (!can_reorder(candidate.bounds(), op->bounds())) {
+                GrOP_INFO("\t\tBackward: Intersects with chain (%s, head opID: %u)\n",
+                          candidate.head()->name(), candidate.head()->uniqueID());
+                break;
+            }
+            if (++i == maxCandidates) {
+                GrOP_INFO("\t\tBackward: Reached max lookback or beginning of op array %d\n", i);
+                break;
+            }
+        }
+    } else {
+        GrOP_INFO("\t\tBackward: FirstOp\n");
+    }
+    if (clip) {
+        clip = fArenas->arenaAlloc()->make<GrAppliedClip>(std::move(*clip));
+        SkDEBUGCODE(fNumClips++;)
+    }
+    fOpChains.emplace_back(std::move(op), processorAnalysis, clip, dstProxyView);
+}
+
+void OpsTask::forwardCombine(const GrCaps& caps) {
+    SkASSERT(!this->isClosed());
+    GrOP_INFO("opsTask: %d ForwardCombine %d ops:\n", this->uniqueID(), fOpChains.count());
+
+    for (int i = 0; i < fOpChains.count() - 1; ++i) {
+        OpChain& chain = fOpChains[i];
+        int maxCandidateIdx = std::min(i + kMaxOpChainDistance, fOpChains.count() - 1);
+        int j = i + 1;
+        while (true) {
+            OpChain& candidate = fOpChains[j];
+            if (candidate.prependChain(&chain, caps, fArenas->arenaAlloc(), fAuditTrail)) {
+                break;
+            }
+            // Stop traversing if we would cause a painter's order violation.
+            if (!can_reorder(chain.bounds(), candidate.bounds())) {
+                GrOP_INFO(
+                        "\t\t%d: chain (%s head opID: %u) -> "
+                        "Intersects with chain (%s, head opID: %u)\n",
+                        i, chain.head()->name(), chain.head()->uniqueID(), candidate.head()->name(),
+                        candidate.head()->uniqueID());
+                break;
+            }
+            if (++j > maxCandidateIdx) {
+                GrOP_INFO("\t\t%d: chain (%s opID: %u) -> Reached max lookahead or end of array\n",
+                          i, chain.head()->name(), chain.head()->uniqueID());
+                break;
+            }
+        }
+    }
+}
+
+GrRenderTask::ExpectedOutcome OpsTask::onMakeClosed(GrRecordingContext* rContext,
+                                                    SkIRect* targetUpdateBounds) {
+    this->forwardCombine(*rContext->priv().caps());
+    if (!this->isColorNoOp()) {
+        GrSurfaceProxy* proxy = this->target(0);
+        // Use the entire backing store bounds since the GPU doesn't clip automatically to the
+        // logical dimensions.
+        SkRect clippedContentBounds = proxy->backingStoreBoundsRect();
+        // TODO: If we can fix up GLPrograms test to always intersect the target proxy bounds
+        // then we can simply assert here that the bounds intersect.
+        if (clippedContentBounds.intersect(fTotalBounds)) {
+            clippedContentBounds.roundOut(&fClippedContentBounds);
+            *targetUpdateBounds = GrNativeRect::MakeIRectRelativeTo(
+                    fTargetOrigin,
+                    this->target(0)->backingStoreDimensions().height(),
+                    fClippedContentBounds);
+            return ExpectedOutcome::kTargetDirty;
+        }
+    }
+    return ExpectedOutcome::kTargetUnchanged;
+}
+
+} // namespace skgpu::v1