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Reland "Reland "[compiler][wasm] Align Frame slots to value size""
This is a reland of 1694925 Minor fix to linkage for constexpr. TBR=ahaas@chromium.org,neis@chromium.org Original change's description: > Reland "[compiler][wasm] Align Frame slots to value size" > > This is a reland of cddaf66 > > Original change's description: > > [compiler][wasm] Align Frame slots to value size > > > > - Adds an AlignedSlotAllocator class and tests, to unify slot > > allocation. This attempts to use alignment holes for smaller > > values. > > - Reworks Frame to use the new allocator for stack slots. > > - Reworks LinkageAllocator to use the new allocator for stack > > slots and for ARMv7 FP register aliasing. > > - Fixes the RegisterAllocator to align spill slots. > > - Fixes InstructionSelector to align spill slots. > > > > Bug: v8:9198 > > > > Change-Id: Ida148db428be89ef95de748ec5fc0e7b0358f523 > > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2512840 > > Commit-Queue: Bill Budge <bbudge@chromium.org> > > Reviewed-by: Georg Neis <neis@chromium.org> > > Reviewed-by: Andreas Haas <ahaas@chromium.org> > > Cr-Commit-Position: refs/heads/master@{#71644} > > Bug: v8:9198 > Change-Id: Ib91fa6746370c38496706341e12d05c7bf999389 > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2633390 > Commit-Queue: Bill Budge <bbudge@chromium.org> > Reviewed-by: Andreas Haas <ahaas@chromium.org> > Reviewed-by: Georg Neis <neis@chromium.org> > Cr-Commit-Position: refs/heads/master@{#72195} Bug: v8:9198 Change-Id: I91e02b823af8ec925dacf075388fb22e3eeb3384 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2640890 Reviewed-by: Bill Budge <bbudge@chromium.org> Commit-Queue: Bill Budge <bbudge@chromium.org> Cr-Commit-Position: refs/heads/master@{#72209}
1 parent 5603f5c commit 352b9ec

16 files changed

Lines changed: 477 additions & 111 deletions

‎BUILD.gn‎

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@@ -2519,6 +2519,8 @@ v8_source_set("v8_base_without_compiler") {
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"src/builtins/constants-table-builder.cc",
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"src/builtins/constants-table-builder.h",
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"src/builtins/profile-data-reader.h",
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"src/codegen/aligned-slot-allocator.cc",
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"src/codegen/aligned-slot-allocator.h",
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"src/codegen/assembler-arch.h",
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"src/codegen/assembler-inl.h",
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"src/codegen/assembler.cc",
@@ -4384,6 +4386,7 @@ v8_component("v8_libbase") {
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if (is_tsan && !build_with_chromium) {
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data += [ "tools/sanitizers/tsan_suppressions.txt" ]
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# llvm-symbolizer uses libstdc++ from the clang package.
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data += [ "//third_party/llvm-build/Release+Asserts/lib/libstdc++.so.6" ]
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}

‎src/codegen/aligned-slot-allocator.cc‎

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// Copyright 2020 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "src/codegen/aligned-slot-allocator.h"
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#include "src/base/bits.h"
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#include "src/base/logging.h"
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namespace v8 {
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namespace internal {
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// Define storage so we can use things like std::min that may take an address.
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constexpr int AlignedSlotAllocator::kSlotSize;
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int AlignedSlotAllocator::NextSlot(int n) const {
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DCHECK(n == 1 || n == 2 || n == 4);
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if (n <= 1 && IsValid(next1_)) return next1_;
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if (n <= 2 && IsValid(next2_)) return next2_;
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DCHECK(IsValid(next4_));
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return next4_;
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}
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int AlignedSlotAllocator::Allocate(int n) {
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DCHECK(n == 1 || n == 2 || n == 4);
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// Check invariants.
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DCHECK_EQ(0, next4_ & 3);
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DCHECK_IMPLIES(IsValid(next2_), (next2_ & 1) == 0);
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// The sentinel value kInvalidSlot is used to indicate no slot.
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// next1_ is the index of the 1 slot fragment, or kInvalidSlot.
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// next2_ is the 2-aligned index of the 2 slot fragment, or kInvalidSlot.
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// next4_ is the 4-aligned index of the next 4 slot group. It is always valid.
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// In order to ensure we only have a single 1- or 2-slot fragment, we greedily
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// use any fragment that satisfies the request.
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int result = kInvalidSlot;
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switch (n) {
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case 1: {
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if (IsValid(next1_)) {
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result = next1_;
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next1_ = kInvalidSlot;
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} else if (IsValid(next2_)) {
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result = next2_;
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next1_ = result + 1;
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next2_ = kInvalidSlot;
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} else {
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result = next4_;
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next1_ = result + 1;
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next2_ = result + 2;
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next4_ += 4;
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}
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break;
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}
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case 2: {
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if (IsValid(next2_)) {
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result = next2_;
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next2_ = kInvalidSlot;
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} else {
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result = next4_;
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next2_ = result + 2;
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next4_ += 4;
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}
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break;
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}
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case 4: {
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result = next4_;
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next4_ += 4;
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break;
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}
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default:
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UNREACHABLE();
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break;
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}
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DCHECK(IsValid(result));
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size_ = std::max(size_, result + n);
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return result;
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}
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int AlignedSlotAllocator::AllocateUnaligned(int n) {
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DCHECK_GE(n, 0);
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// Check invariants.
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DCHECK_EQ(0, next4_ & 3);
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DCHECK_IMPLIES(IsValid(next2_), (next2_ & 1) == 0);
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// Reserve |n| slots at |size_|, invalidate fragments below the new |size_|,
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// and add any new fragments beyond the new |size_|.
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int result = size_;
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size_ += n;
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switch (size_ & 3) {
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case 0: {
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next1_ = next2_ = kInvalidSlot;
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next4_ = size_;
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break;
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}
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case 1: {
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next1_ = size_;
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next2_ = size_ + 1;
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next4_ = size_ + 3;
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break;
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}
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case 2: {
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next1_ = kInvalidSlot;
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next2_ = size_;
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next4_ = size_ + 2;
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break;
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}
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case 3: {
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next1_ = size_;
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next2_ = kInvalidSlot;
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next4_ = size_ + 1;
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break;
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}
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}
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return result;
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}
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int AlignedSlotAllocator::Align(int n) {
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DCHECK(base::bits::IsPowerOfTwo(n));
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DCHECK_LE(n, 4);
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int mask = n - 1;
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int misalignment = size_ & mask;
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int padding = (n - misalignment) & mask;
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AllocateUnaligned(padding);
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return padding;
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}
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} // namespace internal
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} // namespace v8

‎src/codegen/aligned-slot-allocator.h‎

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// Copyright 2020 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef V8_CODEGEN_ALIGNED_SLOT_ALLOCATOR_H_
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#define V8_CODEGEN_ALIGNED_SLOT_ALLOCATOR_H_
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#include "src/base/macros.h"
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#include "src/base/platform/platform.h"
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#include "src/common/globals.h"
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namespace v8 {
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namespace internal {
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// An aligned slot allocator. Allocates groups of 1, 2, or 4 slots such that the
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// first slot of the group is aligned to the group size. The allocator can also
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// allocate unaligned groups of arbitrary size, and an align the number of slots
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// to 1, 2, or 4 slots. The allocator tries to be as thrifty as possible by
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// reusing alignment padding slots in subsequent smaller slot allocations.
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class V8_EXPORT_PRIVATE AlignedSlotAllocator {
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public:
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// Slots are always multiples of pointer-sized units.
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static constexpr int kSlotSize = kSystemPointerSize;
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static int NumSlotsForWidth(int bytes) {
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DCHECK_GT(bytes, 0);
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return (bytes + kSlotSize - 1) / kSlotSize;
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}
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AlignedSlotAllocator() = default;
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// Allocates |n| slots, where |n| must be 1, 2, or 4. Padding slots may be
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// inserted for alignment.
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// Returns the starting index of the slots, which is evenly divisible by |n|.
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int Allocate(int n);
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// Gets the starting index of the slots that would be returned by Allocate(n).
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int NextSlot(int n) const;
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// Allocates the given number of slots at the current end of the slot area,
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// and returns the starting index of the slots. This resets any fragment
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// slots, so subsequent allocations will be after the end of this one.
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// AllocateUnaligned(0) can be used to partition the slot area, for example
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// to make sure tagged values follow untagged values on a Frame.
45+
int AllocateUnaligned(int n);
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47+
// Aligns the slot area so that future allocations begin at the alignment.
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// Returns the number of slots needed to align the slot area.
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int Align(int n);
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// Returns the size of the slot area, in slots. This will be greater than any
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// already allocated slot index.
53+
int Size() const { return size_; }
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private:
56+
static constexpr int kInvalidSlot = -1;
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58+
static bool IsValid(int slot) { return slot > kInvalidSlot; }
59+
60+
int next1_ = kInvalidSlot;
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int next2_ = kInvalidSlot;
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int next4_ = 0;
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int size_ = 0;
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65+
DISALLOW_NEW_AND_DELETE()
66+
};
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68+
} // namespace internal
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} // namespace v8
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#endif // V8_CODEGEN_ALIGNED_SLOT_ALLOCATOR_H_

‎src/compiler/backend/arm/instruction-selector-arm.cc‎

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@@ -499,7 +499,7 @@ void VisitPairAtomicBinOp(InstructionSelector* selector, Node* node,
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500500
void InstructionSelector::VisitStackSlot(Node* node) {
501501
StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
502-
int slot = frame_->AllocateSpillSlot(rep.size());
502+
int slot = frame_->AllocateSpillSlot(rep.size(), rep.alignment());
503503
OperandGenerator g(this);
504504

505505
Emit(kArchStackSlot, g.DefineAsRegister(node),

‎src/compiler/backend/arm64/instruction-selector-arm64.cc‎

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@@ -566,7 +566,7 @@ int32_t LeftShiftForReducedMultiply(Matcher* m) {
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567567
void InstructionSelector::VisitStackSlot(Node* node) {
568568
StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
569-
int slot = frame_->AllocateSpillSlot(rep.size());
569+
int slot = frame_->AllocateSpillSlot(rep.size(), rep.alignment());
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OperandGenerator g(this);
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572572
Emit(kArchStackSlot, g.DefineAsRegister(node),

‎src/compiler/backend/ia32/instruction-selector-ia32.cc‎

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@@ -398,7 +398,7 @@ void VisitRROI8x16SimdShift(InstructionSelector* selector, Node* node,
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399399
void InstructionSelector::VisitStackSlot(Node* node) {
400400
StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
401-
int slot = frame_->AllocateSpillSlot(rep.size());
401+
int slot = frame_->AllocateSpillSlot(rep.size(), rep.alignment());
402402
OperandGenerator g(this);
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404404
Emit(kArchStackSlot, g.DefineAsRegister(node),

‎src/compiler/backend/ppc/instruction-selector-ppc.cc‎

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@@ -155,7 +155,7 @@ void VisitBinop(InstructionSelector* selector, Node* node,
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156156
void InstructionSelector::VisitStackSlot(Node* node) {
157157
StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
158-
int slot = frame_->AllocateSpillSlot(rep.size());
158+
int slot = frame_->AllocateSpillSlot(rep.size(), rep.alignment());
159159
OperandGenerator g(this);
160160

161161
Emit(kArchStackSlot, g.DefineAsRegister(node),

‎src/compiler/backend/register-allocator.cc‎

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@@ -4519,9 +4519,11 @@ void OperandAssigner::AssignSpillSlots() {
45194519
for (SpillRange* range : spill_ranges) {
45204520
data()->tick_counter()->TickAndMaybeEnterSafepoint();
45214521
if (range == nullptr || range->IsEmpty()) continue;
4522-
// Allocate a new operand referring to the spill slot.
45234522
if (!range->HasSlot()) {
4524-
int index = data()->frame()->AllocateSpillSlot(range->byte_width());
4523+
// Allocate a new operand referring to the spill slot, aligned to the
4524+
// operand size.
4525+
int width = range->byte_width();
4526+
int index = data()->frame()->AllocateSpillSlot(width, width);
45254527
range->set_assigned_slot(index);
45264528
}
45274529
}

‎src/compiler/backend/s390/instruction-selector-s390.cc‎

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@@ -680,7 +680,7 @@ void VisitBinOp(InstructionSelector* selector, Node* node,
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681681
void InstructionSelector::VisitStackSlot(Node* node) {
682682
StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
683-
int slot = frame_->AllocateSpillSlot(rep.size());
683+
int slot = frame_->AllocateSpillSlot(rep.size(), rep.alignment());
684684
OperandGenerator g(this);
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686686
Emit(kArchStackSlot, g.DefineAsRegister(node),

‎src/compiler/backend/x64/instruction-selector-x64.cc‎

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@@ -336,7 +336,7 @@ ArchOpcode GetStoreOpcode(StoreRepresentation store_rep) {
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337337
void InstructionSelector::VisitStackSlot(Node* node) {
338338
StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
339-
int slot = frame_->AllocateSpillSlot(rep.size());
339+
int slot = frame_->AllocateSpillSlot(rep.size(), rep.alignment());
340340
OperandGenerator g(this);
341341

342342
Emit(kArchStackSlot, g.DefineAsRegister(node),

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