7be64db45f
This is a reland of cf93071c91
Original change's description:
> [interpreter] Short Star bytecode
>
> Design doc:
> https://docs.google.com/document/d/1g_NExMT78II_KnIYNa9MvyPYIj23qAiFUEsyemY5KRk/edit
>
> This change adds 16 new interpreter opcodes, kStar0 through kStar15, so
> that we can use a single byte to represent the common operation of
> storing to a low-numbered register. This generally reduces the quantity
> of bytecode generated on web sites by 8-9%.
>
> In order to not degrade speed, a couple of other changes are required:
>
> The existing lookahead logic to check for Star after certain other
> bytecode handlers is updated to check for these new short Star codes
> instead. Furthermore, that lookahead logic is updated to contain its own
> copy of the dispatch jump rather than merging control flow with the
> lookahead-failed case, to improve branch prediction.
>
> A bunch of constants use bytecode size in bytes as a proxy for the size
> or complexity of a function, and are adjusted downward proportionally to
> the decrease in generated bytecode size.
>
> Other small drive-by fix: update generate-bytecode-expectations to emit
> \n instead of \r\n on Windows.
>
> Change-Id: I6307c2b0f5794a3a1088bb0fb94f6e1615441ed5
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2641180
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
> Cr-Commit-Position: refs/heads/master@{#72773}
Change-Id: I1afb670c25694498b3989de615858f984a8c7f6f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2698057
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72821}
108 lines
2.4 KiB
Plaintext
108 lines
2.4 KiB
Plaintext
#
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# Autogenerated by generate-bytecode-expectations.
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#
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---
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wrap: yes
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---
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snippet: "
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let x = 10; function f1() {return x;}
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"
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frame size: 1
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parameter count: 1
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bytecode array length: 14
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bytecodes: [
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/* 30 E> */ B(CreateFunctionContext), U8(0), U8(1),
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B(PushContext), R(0),
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B(LdaTheHole),
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B(StaCurrentContextSlot), U8(2),
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/* 42 S> */ B(LdaSmi), I8(10),
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/* 42 E> */ B(StaCurrentContextSlot), U8(2),
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B(LdaUndefined),
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/* 72 S> */ B(Return),
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]
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constant pool: [
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SCOPE_INFO_TYPE,
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]
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handlers: [
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]
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---
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snippet: "
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let x = 10; function f1() {return x;} return x;
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"
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frame size: 1
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parameter count: 1
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bytecode array length: 15
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bytecodes: [
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/* 30 E> */ B(CreateFunctionContext), U8(0), U8(1),
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B(PushContext), R(0),
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B(LdaTheHole),
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B(StaCurrentContextSlot), U8(2),
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/* 42 S> */ B(LdaSmi), I8(10),
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/* 42 E> */ B(StaCurrentContextSlot), U8(2),
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/* 72 S> */ B(LdaImmutableCurrentContextSlot), U8(2),
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/* 81 S> */ B(Return),
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]
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constant pool: [
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SCOPE_INFO_TYPE,
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]
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handlers: [
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]
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---
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snippet: "
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let x = (x = 20); function f1() {return x;}
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"
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frame size: 2
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parameter count: 1
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bytecode array length: 23
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bytecodes: [
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/* 30 E> */ B(CreateFunctionContext), U8(0), U8(1),
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B(PushContext), R(0),
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B(LdaTheHole),
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B(StaCurrentContextSlot), U8(2),
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/* 42 S> */ B(LdaSmi), I8(20),
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B(Star1),
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B(LdaCurrentContextSlot), U8(2),
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/* 45 E> */ B(ThrowReferenceErrorIfHole), U8(1),
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B(Ldar), R(1),
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B(StaCurrentContextSlot), U8(2),
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/* 42 E> */ B(StaCurrentContextSlot), U8(2),
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B(LdaUndefined),
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/* 78 S> */ B(Return),
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]
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constant pool: [
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SCOPE_INFO_TYPE,
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ONE_BYTE_INTERNALIZED_STRING_TYPE ["x"],
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]
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handlers: [
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]
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---
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snippet: "
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let x = 10; x = 20; function f1() {return x;}
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"
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frame size: 1
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parameter count: 1
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bytecode array length: 18
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bytecodes: [
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/* 30 E> */ B(CreateFunctionContext), U8(0), U8(1),
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B(PushContext), R(0),
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B(LdaTheHole),
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B(StaCurrentContextSlot), U8(2),
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/* 42 S> */ B(LdaSmi), I8(10),
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/* 42 E> */ B(StaCurrentContextSlot), U8(2),
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/* 46 S> */ B(LdaSmi), I8(20),
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/* 48 E> */ B(StaCurrentContextSlot), U8(2),
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B(LdaUndefined),
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/* 80 S> */ B(Return),
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]
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constant pool: [
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SCOPE_INFO_TYPE,
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]
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handlers: [
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]
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