Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 544 insertions, 0 deletions

diff --git a/js/src/wasm/WasmBCFrame.cpp b/js/src/wasm/WasmBCFrame.cpp
new file mode 100644
index 0000000000..454f732823
--- /dev/null
+++ b/js/src/wasm/WasmBCFrame.cpp
@@ -0,0 +1,544 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ *
+ * Copyright 2016 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "wasm/WasmBCFrame.h"
+
+#include "wasm/WasmBaselineCompile.h"  // For BaseLocalIter
+#include "wasm/WasmBCClass.h"
+
+#include "jit/MacroAssembler-inl.h"
+#include "wasm/WasmBCClass-inl.h"
+#include "wasm/WasmBCCodegen-inl.h"
+#include "wasm/WasmBCRegDefs-inl.h"
+#include "wasm/WasmBCRegMgmt-inl.h"
+#include "wasm/WasmBCStkMgmt-inl.h"
+
+namespace js {
+namespace wasm {
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// BaseLocalIter methods.
+
+BaseLocalIter::BaseLocalIter(const ValTypeVector& locals,
+                             const ArgTypeVector& args, bool debugEnabled)
+    : locals_(locals),
+      args_(args),
+      argsIter_(args_),
+      index_(0),
+      frameSize_(0),
+      nextFrameSize_(debugEnabled ? DebugFrame::offsetOfFrame() : 0),
+      frameOffset_(INT32_MAX),
+      stackResultPointerOffset_(INT32_MAX),
+      mirType_(MIRType::Undefined),
+      done_(false) {
+  MOZ_ASSERT(args.lengthWithoutStackResults() <= locals.length());
+  settle();
+}
+
+int32_t BaseLocalIter::pushLocal(size_t nbytes) {
+  MOZ_ASSERT(nbytes % 4 == 0 && nbytes <= 16);
+  nextFrameSize_ = AlignBytes(frameSize_, nbytes) + nbytes;
+  return nextFrameSize_;  // Locals grow down so capture base address.
+}
+
+void BaseLocalIter::settle() {
+  MOZ_ASSERT(!done_);
+  frameSize_ = nextFrameSize_;
+
+  if (!argsIter_.done()) {
+    mirType_ = argsIter_.mirType();
+    MIRType concreteType = mirType_;
+    switch (mirType_) {
+      case MIRType::StackResults:
+        // The pointer to stack results is handled like any other argument:
+        // either addressed in place if it is passed on the stack, or we spill
+        // it in the frame if it's in a register.
+        MOZ_ASSERT(args_.isSyntheticStackResultPointerArg(index_));
+        concreteType = MIRType::Pointer;
+        [[fallthrough]];
+      case MIRType::Int32:
+      case MIRType::Int64:
+      case MIRType::Double:
+      case MIRType::Float32:
+      case MIRType::RefOrNull:
+#ifdef ENABLE_WASM_SIMD
+      case MIRType::Simd128:
+#endif
+        if (argsIter_->argInRegister()) {
+          frameOffset_ = pushLocal(MIRTypeToSize(concreteType));
+        } else {
+          frameOffset_ = -(argsIter_->offsetFromArgBase() + sizeof(Frame));
+        }
+        break;
+      default:
+        MOZ_CRASH("Argument type");
+    }
+    if (mirType_ == MIRType::StackResults) {
+      stackResultPointerOffset_ = frameOffset();
+      // Advance past the synthetic stack result pointer argument and fall
+      // through to the next case.
+      argsIter_++;
+      frameSize_ = nextFrameSize_;
+      MOZ_ASSERT(argsIter_.done());
+    } else {
+      return;
+    }
+  }
+
+  if (index_ < locals_.length()) {
+    switch (locals_[index_].kind()) {
+      case ValType::I32:
+      case ValType::I64:
+      case ValType::F32:
+      case ValType::F64:
+#ifdef ENABLE_WASM_SIMD
+      case ValType::V128:
+#endif
+      case ValType::Ref:
+        // TODO/AnyRef-boxing: With boxed immediates and strings, the
+        // debugger must be made aware that AnyRef != Pointer.
+        ASSERT_ANYREF_IS_JSOBJECT;
+        mirType_ = locals_[index_].toMIRType();
+        frameOffset_ = pushLocal(MIRTypeToSize(mirType_));
+        break;
+      default:
+        MOZ_CRASH("Compiler bug: Unexpected local type");
+    }
+    return;
+  }
+
+  done_ = true;
+}
+
+void BaseLocalIter::operator++(int) {
+  MOZ_ASSERT(!done_);
+  index_++;
+  if (!argsIter_.done()) {
+    argsIter_++;
+  }
+  settle();
+}
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Stack map methods.
+
+bool BaseCompiler::createStackMap(const char* who) {
+  const ExitStubMapVector noExtras;
+  return stackMapGenerator_.createStackMap(who, noExtras, masm.currentOffset(),
+                                           HasDebugFrameWithLiveRefs::No, stk_);
+}
+
+bool BaseCompiler::createStackMap(const char* who, CodeOffset assemblerOffset) {
+  const ExitStubMapVector noExtras;
+  return stackMapGenerator_.createStackMap(who, noExtras,
+                                           assemblerOffset.offset(),
+                                           HasDebugFrameWithLiveRefs::No, stk_);
+}
+
+bool BaseCompiler::createStackMap(
+    const char* who, HasDebugFrameWithLiveRefs debugFrameWithLiveRefs) {
+  const ExitStubMapVector noExtras;
+  return stackMapGenerator_.createStackMap(who, noExtras, masm.currentOffset(),
+                                           debugFrameWithLiveRefs, stk_);
+}
+
+bool BaseCompiler::createStackMap(
+    const char* who, const ExitStubMapVector& extras, uint32_t assemblerOffset,
+    HasDebugFrameWithLiveRefs debugFrameWithLiveRefs) {
+  return stackMapGenerator_.createStackMap(who, extras, assemblerOffset,
+                                           debugFrameWithLiveRefs, stk_);
+}
+
+bool MachineStackTracker::cloneTo(MachineStackTracker* dst) {
+  MOZ_ASSERT(dst->vec_.empty());
+  if (!dst->vec_.appendAll(vec_)) {
+    return false;
+  }
+  dst->numPtrs_ = numPtrs_;
+  return true;
+}
+
+bool StackMapGenerator::generateStackmapEntriesForTrapExit(
+    const ArgTypeVector& args, ExitStubMapVector* extras) {
+  return GenerateStackmapEntriesForTrapExit(args, trapExitLayout_,
+                                            trapExitLayoutNumWords_, extras);
+}
+
+bool StackMapGenerator::createStackMap(
+    const char* who, const ExitStubMapVector& extras, uint32_t assemblerOffset,
+    HasDebugFrameWithLiveRefs debugFrameWithLiveRefs, const StkVector& stk) {
+  size_t countedPointers = machineStackTracker.numPtrs() + memRefsOnStk;
+#ifndef DEBUG
+  // An important optimization.  If there are obviously no pointers, as
+  // we expect in the majority of cases, exit quickly.
+  if (countedPointers == 0 &&
+      debugFrameWithLiveRefs == HasDebugFrameWithLiveRefs::No) {
+    // We can skip creating the map if there are no |true| elements in
+    // |extras|.
+    bool extrasHasRef = false;
+    for (bool b : extras) {
+      if (b) {
+        extrasHasRef = true;
+        break;
+      }
+    }
+    if (!extrasHasRef) {
+      return true;
+    }
+  }
+#else
+  // In the debug case, create the stackmap regardless, and cross-check
+  // the pointer-counting below.  We expect the final map to have
+  // |countedPointers| in total.  This doesn't include those in the
+  // DebugFrame, but they do not appear in the map's bitmap.  Note that
+  // |countedPointers| is debug-only from this point onwards.
+  for (bool b : extras) {
+    countedPointers += (b ? 1 : 0);
+  }
+#endif
+
+  // Start with the frame-setup map, and add operand-stack information to
+  // that.  augmentedMst holds live data only within individual calls to
+  // createStackMap.
+  augmentedMst.clear();
+  if (!machineStackTracker.cloneTo(&augmentedMst)) {
+    return false;
+  }
+
+  // At this point, augmentedMst only contains entries covering the
+  // incoming argument area (if any) and for the area allocated by this
+  // function's prologue.  We now need to calculate how far the machine's
+  // stack pointer is below where it was at the start of the body.  But we
+  // must take care not to include any words pushed as arguments to an
+  // upcoming function call, since those words "belong" to the stackmap of
+  // the callee, not to the stackmap of this function.  Note however that
+  // any alignment padding pushed prior to pushing the args *does* belong to
+  // this function.
+  //
+  // That padding is taken into account at the point where
+  // framePushedExcludingOutboundCallArgs is set, viz, in startCallArgs(),
+  // and comprises two components:
+  //
+  // * call->frameAlignAdjustment
+  // * the padding applied to the stack arg area itself.  That is:
+  //   StackArgAreaSize(argTys) - StackArgAreaSizeUnpadded(argTys)
+  Maybe<uint32_t> framePushedExcludingArgs;
+  if (framePushedAtEntryToBody.isNothing()) {
+    // Still in the prologue.  framePushedExcludingArgs remains Nothing.
+    MOZ_ASSERT(framePushedExcludingOutboundCallArgs.isNothing());
+  } else {
+    // In the body.
+    MOZ_ASSERT(masm_.framePushed() >= framePushedAtEntryToBody.value());
+    if (framePushedExcludingOutboundCallArgs.isSome()) {
+      // In the body, and we've potentially pushed some args onto the stack.
+      // We must ignore them when sizing the stackmap.
+      MOZ_ASSERT(masm_.framePushed() >=
+                 framePushedExcludingOutboundCallArgs.value());
+      MOZ_ASSERT(framePushedExcludingOutboundCallArgs.value() >=
+                 framePushedAtEntryToBody.value());
+      framePushedExcludingArgs =
+          Some(framePushedExcludingOutboundCallArgs.value());
+    } else {
+      // In the body, but not with call args on the stack.  The stackmap
+      // must be sized so as to extend all the way "down" to
+      // masm_.framePushed().
+      framePushedExcludingArgs = Some(masm_.framePushed());
+    }
+  }
+
+  if (framePushedExcludingArgs.isSome()) {
+    uint32_t bodyPushedBytes =
+        framePushedExcludingArgs.value() - framePushedAtEntryToBody.value();
+    MOZ_ASSERT(0 == bodyPushedBytes % sizeof(void*));
+    if (!augmentedMst.pushNonGCPointers(bodyPushedBytes / sizeof(void*))) {
+      return false;
+    }
+  }
+
+  // Scan the operand stack, marking pointers in the just-added new
+  // section.
+  MOZ_ASSERT_IF(framePushedAtEntryToBody.isNothing(), stk.empty());
+  MOZ_ASSERT_IF(framePushedExcludingArgs.isNothing(), stk.empty());
+
+  for (const Stk& v : stk) {
+#ifndef DEBUG
+    // We don't track roots in registers, per rationale below, so if this
+    // doesn't hold, something is seriously wrong, and we're likely to get a
+    // GC-related crash.
+    MOZ_RELEASE_ASSERT(v.kind() != Stk::RegisterRef);
+    if (v.kind() != Stk::MemRef) {
+      continue;
+    }
+#else
+    // Take the opportunity to check everything we reasonably can about
+    // operand stack elements.
+    switch (v.kind()) {
+      case Stk::MemI32:
+      case Stk::MemI64:
+      case Stk::MemF32:
+      case Stk::MemF64:
+      case Stk::ConstI32:
+      case Stk::ConstI64:
+      case Stk::ConstF32:
+      case Stk::ConstF64:
+#  ifdef ENABLE_WASM_SIMD
+      case Stk::MemV128:
+      case Stk::ConstV128:
+#  endif
+        // All of these have uninteresting type.
+        continue;
+      case Stk::LocalI32:
+      case Stk::LocalI64:
+      case Stk::LocalF32:
+      case Stk::LocalF64:
+#  ifdef ENABLE_WASM_SIMD
+      case Stk::LocalV128:
+#  endif
+        // These also have uninteresting type.  Check that they live in the
+        // section of stack set up by beginFunction().  The unguarded use of
+        // |value()| here is safe due to the assertion above this loop.
+        MOZ_ASSERT(v.offs() <= framePushedAtEntryToBody.value());
+        continue;
+      case Stk::RegisterI32:
+      case Stk::RegisterI64:
+      case Stk::RegisterF32:
+      case Stk::RegisterF64:
+#  ifdef ENABLE_WASM_SIMD
+      case Stk::RegisterV128:
+#  endif
+        // These also have uninteresting type, but more to the point: all
+        // registers holding live values should have been flushed to the
+        // machine stack immediately prior to the instruction to which this
+        // stackmap pertains.  So these can't happen.
+        MOZ_CRASH("createStackMap: operand stack has Register-non-Ref");
+      case Stk::MemRef:
+        // This is the only case we care about.  We'll handle it after the
+        // switch.
+        break;
+      case Stk::LocalRef:
+        // We need the stackmap to mention this pointer, but it should
+        // already be in the machineStackTracker section created by
+        // beginFunction().
+        MOZ_ASSERT(v.offs() <= framePushedAtEntryToBody.value());
+        continue;
+      case Stk::ConstRef:
+        // This can currently only be a null pointer.
+        MOZ_ASSERT(v.refval() == 0);
+        continue;
+      case Stk::RegisterRef:
+        // This can't happen, per rationale above.
+        MOZ_CRASH("createStackMap: operand stack contains RegisterRef");
+      default:
+        MOZ_CRASH("createStackMap: unknown operand stack element");
+    }
+#endif
+    // v.offs() holds masm.framePushed() at the point immediately after it
+    // was pushed on the stack.  Since it's still on the stack,
+    // masm.framePushed() can't be less.
+    MOZ_ASSERT(v.offs() <= framePushedExcludingArgs.value());
+    uint32_t offsFromMapLowest = framePushedExcludingArgs.value() - v.offs();
+    MOZ_ASSERT(0 == offsFromMapLowest % sizeof(void*));
+    augmentedMst.setGCPointer(offsFromMapLowest / sizeof(void*));
+  }
+
+  // Create the final StackMap.  The initial map is zeroed out, so there's
+  // no need to write zero bits in it.
+  const uint32_t extraWords = extras.length();
+  const uint32_t augmentedMstWords = augmentedMst.length();
+  const uint32_t numMappedWords = extraWords + augmentedMstWords;
+  StackMap* stackMap = StackMap::create(numMappedWords);
+  if (!stackMap) {
+    return false;
+  }
+
+  {
+    // First the exit stub extra words, if any.
+    uint32_t i = 0;
+    for (bool b : extras) {
+      if (b) {
+        stackMap->setBit(i);
+      }
+      i++;
+    }
+  }
+  {
+    // Followed by the "main" part of the map.
+    //
+    // This is really just a bit-array copy, so it is reasonable to ask
+    // whether the representation of MachineStackTracker could be made more
+    // similar to that of StackMap, so that the copy could be done with
+    // `memcpy`.  Unfortunately it's not so simple; see comment on `class
+    // MachineStackTracker` for details.
+    MachineStackTracker::Iter iter(augmentedMst);
+    while (true) {
+      size_t i = iter.get();
+      if (i == MachineStackTracker::Iter::FINISHED) {
+        break;
+      }
+      stackMap->setBit(extraWords + i);
+    }
+  }
+
+  stackMap->setExitStubWords(extraWords);
+
+  // Record in the map, how far down from the highest address the Frame* is.
+  // Take the opportunity to check that we haven't marked any part of the
+  // Frame itself as a pointer.
+  stackMap->setFrameOffsetFromTop(numStackArgWords +
+                                  sizeof(Frame) / sizeof(void*));
+#ifdef DEBUG
+  for (uint32_t i = 0; i < sizeof(Frame) / sizeof(void*); i++) {
+    MOZ_ASSERT(stackMap->getBit(stackMap->header.numMappedWords -
+                                stackMap->header.frameOffsetFromTop + i) == 0);
+  }
+#endif
+
+  // Note the presence of a DebugFrame with live pointers, if any.
+  if (debugFrameWithLiveRefs != HasDebugFrameWithLiveRefs::No) {
+    stackMap->setHasDebugFrameWithLiveRefs();
+  }
+
+  // Add the completed map to the running collection thereof.
+  if (!stackMaps_->add((uint8_t*)(uintptr_t)assemblerOffset, stackMap)) {
+    stackMap->destroy();
+    return false;
+  }
+
+#ifdef DEBUG
+  {
+    // Crosscheck the map pointer counting.
+    uint32_t nw = stackMap->header.numMappedWords;
+    uint32_t np = 0;
+    for (uint32_t i = 0; i < nw; i++) {
+      np += stackMap->getBit(i);
+    }
+    MOZ_ASSERT(size_t(np) == countedPointers);
+  }
+#endif
+
+  return true;
+}
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Stack frame methods.
+
+void BaseStackFrame::zeroLocals(BaseRegAlloc* ra) {
+  MOZ_ASSERT(varLow_ != UINT32_MAX);
+
+  if (varLow_ == varHigh_) {
+    return;
+  }
+
+  static const uint32_t wordSize = sizeof(void*);
+
+  // The adjustments to 'low' by the size of the item being stored compensates
+  // for the fact that locals offsets are the offsets from Frame to the bytes
+  // directly "above" the locals in the locals area.  See comment at Local.
+
+  // On 64-bit systems we may have 32-bit alignment for the local area as it
+  // may be preceded by parameters and prologue/debug data.
+
+  uint32_t low = varLow_;
+  if (low % wordSize) {
+    masm.store32(Imm32(0), Address(sp_, localOffset(low + 4)));
+    low += 4;
+  }
+  MOZ_ASSERT(low % wordSize == 0);
+
+  const uint32_t high = AlignBytes(varHigh_, wordSize);
+
+  // An UNROLL_LIMIT of 16 is chosen so that we only need an 8-bit signed
+  // immediate to represent the offset in the store instructions in the loop
+  // on x64.
+
+  const uint32_t UNROLL_LIMIT = 16;
+  const uint32_t initWords = (high - low) / wordSize;
+  const uint32_t tailWords = initWords % UNROLL_LIMIT;
+  const uint32_t loopHigh = high - (tailWords * wordSize);
+
+  // With only one word to initialize, just store an immediate zero.
+
+  if (initWords == 1) {
+    masm.storePtr(ImmWord(0), Address(sp_, localOffset(low + wordSize)));
+    return;
+  }
+
+  // For other cases, it's best to have a zero in a register.
+  //
+  // One can do more here with SIMD registers (store 16 bytes at a time) or
+  // with instructions like STRD on ARM (store 8 bytes at a time), but that's
+  // for another day.
+
+  RegI32 zero = ra->needI32();
+  masm.mov(ImmWord(0), zero);
+
+  // For the general case we want to have a loop body of UNROLL_LIMIT stores
+  // and then a tail of less than UNROLL_LIMIT stores.  When initWords is less
+  // than 2*UNROLL_LIMIT the loop trip count is at most 1 and there is no
+  // benefit to having the pointer calculations and the compare-and-branch.
+  // So we completely unroll when we have initWords < 2 * UNROLL_LIMIT.  (In
+  // this case we'll end up using 32-bit offsets on x64 for up to half of the
+  // stores, though.)
+
+  // Fully-unrolled case.
+
+  if (initWords < 2 * UNROLL_LIMIT) {
+    for (uint32_t i = low; i < high; i += wordSize) {
+      masm.storePtr(zero, Address(sp_, localOffset(i + wordSize)));
+    }
+    ra->freeI32(zero);
+    return;
+  }
+
+  // Unrolled loop with a tail. Stores will use negative offsets. That's OK
+  // for x86 and ARM, at least.
+
+  // Compute pointer to the highest-addressed slot on the frame.
+  RegI32 p = ra->needI32();
+  masm.computeEffectiveAddress(Address(sp_, localOffset(low + wordSize)), p);
+
+  // Compute pointer to the lowest-addressed slot on the frame that will be
+  // initialized by the loop body.
+  RegI32 lim = ra->needI32();
+  masm.computeEffectiveAddress(Address(sp_, localOffset(loopHigh + wordSize)),
+                               lim);
+
+  // The loop body.  Eventually we'll have p == lim and exit the loop.
+  Label again;
+  masm.bind(&again);
+  for (uint32_t i = 0; i < UNROLL_LIMIT; ++i) {
+    masm.storePtr(zero, Address(p, -(wordSize * i)));
+  }
+  masm.subPtr(Imm32(UNROLL_LIMIT * wordSize), p);
+  masm.branchPtr(Assembler::LessThan, lim, p, &again);
+
+  // The tail.
+  for (uint32_t i = 0; i < tailWords; ++i) {
+    masm.storePtr(zero, Address(p, -(wordSize * i)));
+  }
+
+  ra->freeI32(p);
+  ra->freeI32(lim);
+  ra->freeI32(zero);
+}
+
+}  // namespace wasm
+}  // namespace js