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feat: optimize string literal tostack behavior #2945

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merged 2 commits into from
Sep 6, 2025
Merged

feat: optimize string literal tostack behavior #2945

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6165368
feat: optimize string literal tostack behavior
HerrCai0907 Sep 5, 2025
4fb803f
fix
HerrCai0907 Sep 5, 2025
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38 changes: 31 additions & 7 deletions src/compiler.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -55,11 +55,11 @@ import {
SideEffects,
SwitchBuilder,
ExpressionRunnerFlags,
isConstZero,
isConstNegZero,
isConstExpressionNaN,
ensureType,
createType
createType,
getConstValueInteger
} from "./module";

import {
Expand Down Expand Up @@ -451,6 +451,8 @@ export class Compiler extends DiagnosticEmitter {
memorySegments: MemorySegment[] = [];
/** Map of already compiled static string segments. */
stringSegments: Map<string,MemorySegment> = new Map();
/** Set of static GC object offsets. tostack is unnecessary for them. */
staticGcObjectOffsets: Map<i32, Set<i32>> = new Map();
/** Function table being compiled. First elem is blank. */
functionTable: Function[] = [];
/** Arguments length helper global. */
Expand Down Expand Up @@ -1939,7 +1941,16 @@ export class Compiler extends DiagnosticEmitter {
stringSegment = this.addRuntimeMemorySegment(buf);
segments.set(stringValue, stringSegment);
}
return i64_add(stringSegment.offset, i64_new(totalOverhead));
let stringOffset = i64_add(stringSegment.offset, i64_new(totalOverhead));
let staticGcObjectOffsets = this.staticGcObjectOffsets;
if (staticGcObjectOffsets.has(i64_high(stringOffset))) {
assert(staticGcObjectOffsets.get(i64_high(stringOffset))).add(i64_low(stringOffset));
} else {
let s = new Set<i32>();
s.add(i64_low(stringOffset));
staticGcObjectOffsets.set(i64_high(stringOffset), s);
}
return stringOffset;
}

/** Writes a series of static values of the specified type to a buffer. */
Expand Down Expand Up @@ -6754,6 +6765,21 @@ export class Compiler extends DiagnosticEmitter {
stub.set(CommonFlags.Compiled);
}

private needToStack(expr: ExpressionRef): bool {
const precomp = this.module.runExpression(expr, ExpressionRunnerFlags.Default);
// cannot precompute, so must go to stack
if (precomp == 0) return true;
const value = getConstValueInteger(precomp, this.options.isWasm64);
// zero constant doesn't need to go to stack
if (i64_eq(value, i64_zero)) return false;
// static GC objects doesn't need to go to stack
let staticGcObjectOffsets = this.staticGcObjectOffsets;
if (staticGcObjectOffsets.has(i64_high(value))) {
if (assert(staticGcObjectOffsets.get(i64_high(value))).has(i64_low(value))) return false;
}
return true;
}

/** Marks managed call operands for the shadow stack. */
private operandsTostack(signature: Signature, operands: ExpressionRef[]): void {
if (!this.options.stackSize) return;
Expand All @@ -6763,8 +6789,7 @@ export class Compiler extends DiagnosticEmitter {
if (thisType) {
if (thisType.isManaged) {
let operand = operands[0];
let precomp = module.runExpression(operand, ExpressionRunnerFlags.Default);
if (!precomp || !isConstZero(precomp)) { // otherwise unnecessary
if (this.needToStack(operand)) {
operands[operandIndex] = module.tostack(operand);
}
}
Expand All @@ -6777,8 +6802,7 @@ export class Compiler extends DiagnosticEmitter {
let paramType = parameterTypes[parameterIndex];
if (paramType.isManaged) {
let operand = operands[operandIndex];
let precomp = module.runExpression(operand, ExpressionRunnerFlags.Default);
if (!precomp || !isConstZero(precomp)) { // otherwise unnecessary
if (this.needToStack(operand)) {
operands[operandIndex] = module.tostack(operand);
}
}
Expand Down
12 changes: 12 additions & 0 deletions src/module.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -3038,6 +3038,18 @@ export function getConstValueI64High(expr: ExpressionRef): i32 {
return binaryen._BinaryenConstGetValueI64High(expr);
}

export function getConstValueInteger(expr: ExpressionRef, isWasm64: bool): i64 {
let lo: i32 = 0;
let hi: i32 = 0;
if (isWasm64) {
lo = getConstValueI64Low(expr);
hi = getConstValueI64High(expr);
} else {
lo = getConstValueI32(expr);
}
return i64_new(lo, hi);
}

export function getConstValueF32(expr: ExpressionRef): f32 {
return binaryen._BinaryenConstGetValueF32(expr);
}
Expand Down
39 changes: 3 additions & 36 deletions tests/compiler/NonNullable.debug.wat
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Original file line number Diff line number Diff line change
Expand Up @@ -357,28 +357,15 @@
(local $0 i32)
(local $1 i32)
global.get $~lib/memory/__stack_pointer
i32.const 12
i32.const 8
i32.sub
global.set $~lib/memory/__stack_pointer
call $~stack_check
global.get $~lib/memory/__stack_pointer
i64.const 0
i64.store
global.get $~lib/memory/__stack_pointer
i32.const 0
i32.store offset=8
i32.const 32
local.set $1
global.get $~lib/memory/__stack_pointer
local.get $1
i32.store
local.get $1
i32.const 32
local.set $1
global.get $~lib/memory/__stack_pointer
local.get $1
i32.store offset=4
local.get $1
call $~lib/string/String.__eq
i32.eqz
if
Expand All @@ -390,17 +377,7 @@
unreachable
end
i32.const 112
local.set $1
global.get $~lib/memory/__stack_pointer
local.get $1
i32.store
local.get $1
i32.const 112
local.set $1
global.get $~lib/memory/__stack_pointer
local.get $1
i32.store offset=4
local.get $1
call $~lib/string/String.__eq
i32.eqz
if
Expand All @@ -412,17 +389,7 @@
unreachable
end
i32.const 144
local.set $1
global.get $~lib/memory/__stack_pointer
local.get $1
i32.store
local.get $1
i32.const 144
local.set $1
global.get $~lib/memory/__stack_pointer
local.get $1
i32.store offset=4
local.get $1
call $~lib/string/String.__eq
i32.eqz
if
Expand All @@ -436,7 +403,7 @@
global.get $~lib/memory/__stack_pointer
global.get $NonNullable/z
local.tee $0
i32.store offset=8
i32.store offset=4
local.get $0
if (result i32)
local.get $0
Expand All @@ -462,7 +429,7 @@
local.get $1
call $NonNullable/safetyCheck<~lib/string/String|null>
global.get $~lib/memory/__stack_pointer
i32.const 12
i32.const 8
i32.add
global.set $~lib/memory/__stack_pointer
)
Expand Down
27 changes: 3 additions & 24 deletions tests/compiler/NonNullable.release.wat
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@
(start $~start)
(func $~start
global.get $~lib/memory/__stack_pointer
i32.const 12
i32.const 8
i32.sub
global.set $~lib/memory/__stack_pointer
block $folding-inner0
Expand All @@ -33,15 +33,6 @@
global.get $~lib/memory/__stack_pointer
i64.const 0
i64.store
global.get $~lib/memory/__stack_pointer
i32.const 0
i32.store offset=8
global.get $~lib/memory/__stack_pointer
i32.const 1056
i32.store
global.get $~lib/memory/__stack_pointer
i32.const 1056
i32.store offset=4
i32.const 1056
i32.const 1056
call $~lib/string/String.__eq
Expand All @@ -54,12 +45,6 @@
call $~lib/builtins/abort
unreachable
end
global.get $~lib/memory/__stack_pointer
i32.const 1136
i32.store
global.get $~lib/memory/__stack_pointer
i32.const 1136
i32.store offset=4
i32.const 1136
i32.const 1136
call $~lib/string/String.__eq
Expand All @@ -72,12 +57,6 @@
call $~lib/builtins/abort
unreachable
end
global.get $~lib/memory/__stack_pointer
i32.const 1168
i32.store
global.get $~lib/memory/__stack_pointer
i32.const 1168
i32.store offset=4
i32.const 1168
i32.const 1168
call $~lib/string/String.__eq
Expand All @@ -92,7 +71,7 @@
end
global.get $~lib/memory/__stack_pointer
i32.const 1248
i32.store offset=8
i32.store offset=4
global.get $~lib/memory/__stack_pointer
i32.const 1248
i32.store
Expand Down Expand Up @@ -126,7 +105,7 @@
i32.add
global.set $~lib/memory/__stack_pointer
global.get $~lib/memory/__stack_pointer
i32.const 12
i32.const 8
i32.add
global.set $~lib/memory/__stack_pointer
return
Expand Down
65 changes: 21 additions & 44 deletions tests/compiler/bindings/esm.debug.wat
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Original file line number Diff line number Diff line change
Expand Up @@ -124,6 +124,27 @@
(export "functionFunction" (func $export:bindings/esm/functionFunction))
(func $start:bindings/esm~anonymous|0
)
(func $start:bindings/esm
i32.const 128
i32.const 1
f64.const 42
f64.const 0
f64.const 0
f64.const 0
f64.const 0
call $~lib/builtins/trace
i32.const 160
call $~lib/bindings/dom/console.log
global.get $~lib/bindings/dom/Math.E
call $~lib/bindings/dom/Math.log
drop
global.get $bindings/esm/immutableGlobal
drop
global.get $bindings/esm/immutableGlobalNested
drop
call $bindings/esm/Date_getTimezoneOffset
drop
)
(func $bindings/esm/plainFunction (param $a i32) (param $b i32) (result i32)
local.get $a
local.get $b
Expand Down Expand Up @@ -3081,50 +3102,6 @@
unreachable
end
)
(func $start:bindings/esm
(local $0 i32)
global.get $~lib/memory/__stack_pointer
i32.const 4
i32.sub
global.set $~lib/memory/__stack_pointer
call $~stack_check
global.get $~lib/memory/__stack_pointer
i32.const 0
i32.store
i32.const 128
local.set $0
global.get $~lib/memory/__stack_pointer
local.get $0
i32.store
local.get $0
i32.const 1
f64.const 42
f64.const 0
f64.const 0
f64.const 0
f64.const 0
call $~lib/builtins/trace
i32.const 160
local.set $0
global.get $~lib/memory/__stack_pointer
local.get $0
i32.store
local.get $0
call $~lib/bindings/dom/console.log
global.get $~lib/bindings/dom/Math.E
call $~lib/bindings/dom/Math.log
drop
global.get $bindings/esm/immutableGlobal
drop
global.get $bindings/esm/immutableGlobalNested
drop
call $bindings/esm/Date_getTimezoneOffset
drop
global.get $~lib/memory/__stack_pointer
i32.const 4
i32.add
global.set $~lib/memory/__stack_pointer
)
(func $bindings/esm/bufferFunction (param $a i32) (param $b i32) (result i32)
(local $aByteLength i32)
(local $bByteLength i32)
Expand Down
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