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kripkenkripken
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Group reference types in binary format. (#4774)
Grouping all references together makes it easier for baseline compilers to zero out memory (as the zeroing out may be different for MVP types vs. references). This puts all references together, either at the start or the end. As a heuristic for that we see if the first local is a reference. As the optimizer will sort locals by frequency, this ensures that the most-frequent local stays in index 0. Fixes #4773. See more details there
1 parent a82e2db commit 9831b36

5 files changed

+182
-7
lines changed

‎src/wasm/wasm-stack.cpp

Lines changed: 23 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2327,6 +2327,29 @@ void BinaryInstWriter::mapLocalsAndEmitHeader() {
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}
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}
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countScratchLocals();
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if (parent.getModule()->features.hasReferenceTypes()) {
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// Sort local types in a way that keeps all MVP types together and all
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// reference types together. E.g. it is helpful to avoid a block of i32s in
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// between blocks of different reference types, since clearing out reference
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// types may require different work.
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//
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// See https://github.com/WebAssembly/binaryen/issues/4773
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//
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// In order to decide whether to put MVP types or reference types first,
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// look at the type of the first local. In an optimized binary we will have
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// sorted the locals by frequency of uses, so this way we'll keep the most
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// commonly-used local at the top, which should work well in many cases.
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bool refsFirst = !localTypes.empty() && localTypes[0].isRef();
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std::stable_sort(localTypes.begin(), localTypes.end(), [&](Type a, Type b) {
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if (refsFirst) {
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return a.isRef() && !b.isRef();
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} else {
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return !a.isRef() && b.isRef();
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}
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});
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}
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std::unordered_map<Type, size_t> currLocalsByType;
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for (Index i = func->getVarIndexBase(); i < func->getNumLocals(); i++) {
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Index j = 0;

‎test/typed-function-references.wast

Lines changed: 41 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -41,4 +41,45 @@
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)
4242
)
4343
)
44+
(func $ref-types-first
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;; 6 reference types and 3 MVP types. The binary format should emit all the
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;; reference types first since a reference type appears first. In addition,
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;; types should be emitted in blocks there, that is, locals of identical
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;; types should be adjacent.
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(local $r1 (ref null $mixed_results))
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(local $r2 (ref null $mixed_results))
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(local $i1 i32)
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(local $r3 anyref)
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(local $i2 i64)
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(local $r4 anyref)
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(local $i3 i64)
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(local $r5 anyref)
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(local $r6 funcref)
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)
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(func $mvp-types-first
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;; Reversed from before, now an MVP type appears first, so they should all
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;; be before reference types in the binary format.
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(local $i1 i32) ;; only this local was moved up.
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(local $r1 (ref null $mixed_results))
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(local $r2 (ref null $mixed_results))
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(local $r3 anyref)
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(local $i2 i64)
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(local $r4 anyref)
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(local $i3 i64)
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(local $r5 anyref)
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(local $r6 funcref)
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)
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(func $mvp-types-first-param (param $r0 (ref null $mixed_results))
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;; As before, but now there is a reference type *parameter*. We should
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;; ignore that and sort as in the last function.
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(local $i1 i32) ;; only this local was moved up.
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(local $r1 (ref null $mixed_results))
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(local $r2 (ref null $mixed_results))
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(local $r3 anyref)
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(local $i2 i64)
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(local $r4 anyref)
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(local $i3 i64)
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(local $r5 anyref)
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(local $r6 funcref)
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)
4485
)

‎test/typed-function-references.wast.from-wast

Lines changed: 38 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,5 @@
11
(module
2+
(type $mixed_results (func (result anyref f32 anyref f32)))
23
(type $none_=>_none (func))
34
(type $i32-i32 (func (param i32) (result i32)))
45
(type $=>eqref (func (result eqref)))
@@ -8,7 +9,7 @@
89
(type $f64_=>_ref_null<_->_eqref> (func (param f64) (result (ref null $=>eqref))))
910
(type $=>anyref (func (result anyref)))
1011
(type $none_=>_i32_ref?|$mixed_results|_f64 (func (result i32 (ref null $mixed_results) f64)))
11-
(type $mixed_results (func (result anyref f32 anyref f32)))
12+
(type $ref?|$mixed_results|_=>_none (func (param (ref null $mixed_results))))
1213
(elem declare func $call-ref $call-ref-more)
1314
(func $call-ref
1415
(call_ref
@@ -62,4 +63,40 @@
6263
)
6364
)
6465
)
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(func $ref-types-first
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(local $r1 (ref null $mixed_results))
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(local $r2 (ref null $mixed_results))
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(local $i1 i32)
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(local $r3 anyref)
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(local $i2 i64)
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(local $r4 anyref)
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(local $i3 i64)
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(local $r5 anyref)
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(local $r6 funcref)
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(nop)
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)
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(func $mvp-types-first
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(local $i1 i32)
80+
(local $r1 (ref null $mixed_results))
81+
(local $r2 (ref null $mixed_results))
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(local $r3 anyref)
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(local $i2 i64)
84+
(local $r4 anyref)
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(local $i3 i64)
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(local $r5 anyref)
87+
(local $r6 funcref)
88+
(nop)
89+
)
90+
(func $mvp-types-first-param (param $r0 (ref null $mixed_results))
91+
(local $i1 i32)
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(local $r1 (ref null $mixed_results))
93+
(local $r2 (ref null $mixed_results))
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(local $r3 anyref)
95+
(local $i2 i64)
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(local $r4 anyref)
97+
(local $i3 i64)
98+
(local $r5 anyref)
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(local $r6 funcref)
100+
(nop)
101+
)
65102
)

‎test/typed-function-references.wast.fromBinary

Lines changed: 40 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,15 @@
11
(module
2+
(type $mixed_results (func (result anyref f32 anyref f32)))
23
(type $none_=>_none (func))
34
(type $i32-i32 (func (param i32) (result i32)))
4-
(type $mixed_results (func (result anyref f32 anyref f32)))
55
(type $=>eqref (func (result eqref)))
66
(type $ref|$i32-i32|_=>_i32 (func (param (ref $i32-i32)) (result i32)))
77
(type $ref?|$i32-i32|_=>_i32 (func (param (ref null $i32-i32)) (result i32)))
88
(type $none_=>_i32 (func (result i32)))
99
(type $f64_=>_ref_null<_->_eqref> (func (param f64) (result (ref null $=>eqref))))
1010
(type $=>anyref (func (result anyref)))
1111
(type $none_=>_i32_ref?|$mixed_results|_f64 (func (result i32 (ref null $mixed_results) f64)))
12+
(type $ref?|$mixed_results|_=>_none (func (param (ref null $mixed_results))))
1213
(elem declare func $call-ref $call-ref-more)
1314
(func $call-ref
1415
(call_ref
@@ -53,8 +54,8 @@
5354
)
5455
(func $type-only-in-tuple-local
5556
(local $x i32)
56-
(local $1 (ref null $=>anyref))
57-
(local $2 f64)
57+
(local $1 f64)
58+
(local $2 (ref null $=>anyref))
5859
(nop)
5960
)
6061
(func $type-only-in-tuple-block
@@ -92,5 +93,41 @@
9293
)
9394
)
9495
)
96+
(func $ref-types-first
97+
(local $r1 (ref null $mixed_results))
98+
(local $r2 (ref null $mixed_results))
99+
(local $r3 anyref)
100+
(local $r4 anyref)
101+
(local $r5 anyref)
102+
(local $r6 funcref)
103+
(local $i1 i32)
104+
(local $i2 i64)
105+
(local $i3 i64)
106+
(nop)
107+
)
108+
(func $mvp-types-first
109+
(local $i1 i32)
110+
(local $i2 i64)
111+
(local $i3 i64)
112+
(local $r1 (ref null $mixed_results))
113+
(local $r2 (ref null $mixed_results))
114+
(local $r3 anyref)
115+
(local $r4 anyref)
116+
(local $r5 anyref)
117+
(local $r6 funcref)
118+
(nop)
119+
)
120+
(func $mvp-types-first-param (param $r0 (ref null $mixed_results))
121+
(local $i1 i32)
122+
(local $i2 i64)
123+
(local $i3 i64)
124+
(local $r1 (ref null $mixed_results))
125+
(local $r2 (ref null $mixed_results))
126+
(local $r3 anyref)
127+
(local $r4 anyref)
128+
(local $r5 anyref)
129+
(local $r6 funcref)
130+
(nop)
131+
)
95132
)
96133

‎test/typed-function-references.wast.fromBinary.noDebugInfo

Lines changed: 40 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,15 @@
11
(module
2+
(type $none_=>_anyref_f32_anyref_f32 (func (result anyref f32 anyref f32)))
23
(type $none_=>_none (func))
34
(type $i32_=>_i32 (func (param i32) (result i32)))
4-
(type $none_=>_anyref_f32_anyref_f32 (func (result anyref f32 anyref f32)))
55
(type $none_=>_eqref (func (result eqref)))
66
(type $ref|i32_->_i32|_=>_i32 (func (param (ref $i32_=>_i32)) (result i32)))
77
(type $ref?|i32_->_i32|_=>_i32 (func (param (ref null $i32_=>_i32)) (result i32)))
88
(type $none_=>_i32 (func (result i32)))
99
(type $f64_=>_ref?|none_->_eqref| (func (param f64) (result (ref null $none_=>_eqref))))
1010
(type $none_=>_anyref (func (result anyref)))
1111
(type $none_=>_i32_ref?|none_->_anyref_f32_anyref_f32|_f64 (func (result i32 (ref null $none_=>_anyref_f32_anyref_f32) f64)))
12+
(type $ref?|none_->_anyref_f32_anyref_f32|_=>_none (func (param (ref null $none_=>_anyref_f32_anyref_f32))))
1213
(elem declare func $0 $2)
1314
(func $0
1415
(call_ref
@@ -53,8 +54,8 @@
5354
)
5455
(func $7
5556
(local $0 i32)
56-
(local $1 (ref null $none_=>_anyref))
57-
(local $2 f64)
57+
(local $1 f64)
58+
(local $2 (ref null $none_=>_anyref))
5859
(nop)
5960
)
6061
(func $8
@@ -92,5 +93,41 @@
9293
)
9394
)
9495
)
96+
(func $9
97+
(local $0 (ref null $none_=>_anyref_f32_anyref_f32))
98+
(local $1 (ref null $none_=>_anyref_f32_anyref_f32))
99+
(local $2 anyref)
100+
(local $3 anyref)
101+
(local $4 anyref)
102+
(local $5 funcref)
103+
(local $6 i32)
104+
(local $7 i64)
105+
(local $8 i64)
106+
(nop)
107+
)
108+
(func $10
109+
(local $0 i32)
110+
(local $1 i64)
111+
(local $2 i64)
112+
(local $3 (ref null $none_=>_anyref_f32_anyref_f32))
113+
(local $4 (ref null $none_=>_anyref_f32_anyref_f32))
114+
(local $5 anyref)
115+
(local $6 anyref)
116+
(local $7 anyref)
117+
(local $8 funcref)
118+
(nop)
119+
)
120+
(func $11 (param $0 (ref null $none_=>_anyref_f32_anyref_f32))
121+
(local $1 i32)
122+
(local $2 i64)
123+
(local $3 i64)
124+
(local $4 (ref null $none_=>_anyref_f32_anyref_f32))
125+
(local $5 (ref null $none_=>_anyref_f32_anyref_f32))
126+
(local $6 anyref)
127+
(local $7 anyref)
128+
(local $8 anyref)
129+
(local $9 funcref)
130+
(nop)
131+
)
95132
)
96133

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