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-rw-r--r--src/wasm2js.h56
-rw-r--r--test/wasm2js/br_table_hoisting.2asm.js1
-rw-r--r--test/wasm2js/br_table_hoisting.2asm.js.opt2
-rw-r--r--test/wasm2js/br_table_temp.2asm.js.opt3
-rw-r--r--test/wasm2js/excess_fallthrough.2asm.js55
-rw-r--r--test/wasm2js/excess_fallthrough.2asm.js.opt36
-rw-r--r--test/wasm2js/excess_fallthrough.wast21
-rw-r--r--test/wasm2js/switch.2asm.js1
8 files changed, 137 insertions, 38 deletions
diff --git a/src/wasm2js.h b/src/wasm2js.h
index 25c51f490..624847f7d 100644
--- a/src/wasm2js.h
+++ b/src/wasm2js.h
@@ -1013,43 +1013,6 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
Expression* defaultBody = nullptr; // default must be last in asm.js
Ref visitSwitch(Switch* curr) {
-#if 0
- // Simple switch emitting. This is valid but may lead to block nesting of a size
- // that JS engines can't handle.
- Ref ret = ValueBuilder::makeBlock();
- Ref condition = visit(curr->condition, EXPRESSION_RESULT);
- Ref theSwitch =
- ValueBuilder::makeSwitch(makeAsmCoercion(condition, ASM_INT));
- ret[1]->push_back(theSwitch);
- // First, group the switch targets.
- std::map<Name, std::vector<Index>> targetIndexes;
- for (size_t i = 0; i < curr->targets.size(); i++) {
- targetIndexes[curr->targets[i]].push_back(i);
- }
- // Emit group by group.
- for (auto& pair : targetIndexes) {
- auto target = pair.first;
- auto& indexes = pair.second;
- if (target != curr->default_) {
- for (auto i : indexes) {
- ValueBuilder::appendCaseToSwitch(theSwitch,
- ValueBuilder::makeNum(i));
- }
- ValueBuilder::appendCodeToSwitch(
- theSwitch, blockify(makeBreakOrContinue(target)), false);
- } else {
- // For the group going to the same place as the default, we can just
- // emit the default itself, which we do at the end.
- }
- }
- // TODO: if the group the default is in is not the largest, we can turn
- // the largest into
- // the default by using a local and a check on the range
- ValueBuilder::appendDefaultToSwitch(theSwitch);
- ValueBuilder::appendCodeToSwitch(
- theSwitch, blockify(makeBreakOrContinue(curr->default_)), false);
- return ret;
-#else
// Even without optimizations, we work hard here to emit minimal and
// especially minimally-nested code, since otherwise we may get block
// nesting of a size that JS engines can't handle.
@@ -1064,6 +1027,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
// Emit first any hoisted groups.
auto& hoistedCases = switchProcessor.hoistedSwitchCases[curr];
std::set<Name> emittedTargets;
+ bool hoistedEndsWithUnreachable = false;
for (auto& case_ : hoistedCases) {
auto target = case_.target;
auto& code = case_.code;
@@ -1080,8 +1044,23 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
for (auto* c : code) {
ValueBuilder::appendCodeToSwitch(
theSwitch, blockify(visit(c, NO_RESULT)), false);
+ hoistedEndsWithUnreachable = c->type == unreachable;
}
}
+ // After the hoisted cases, if any remain we must make sure not to
+ // fall through into them. If no code was hoisted, this is unnecessary,
+ // and if the hoisted code ended with an unreachable it also is not
+ // necessary.
+ bool stoppedFurtherFallthrough = false;
+ auto stopFurtherFallthrough = [&]() {
+ if (!stoppedFurtherFallthrough && !hoistedCases.empty() &&
+ !hoistedEndsWithUnreachable) {
+ stoppedFurtherFallthrough = true;
+ ValueBuilder::appendCodeToSwitch(
+ theSwitch, blockify(ValueBuilder::makeBreak(IString())), false);
+ }
+ };
+
// Emit any remaining groups by just emitting branches to their code,
// which will appear outside the switch.
for (auto& pair : targetIndexes) {
@@ -1090,6 +1069,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
if (emittedTargets.count(target)) {
continue;
}
+ stopFurtherFallthrough();
if (target != curr->default_) {
for (auto i : indexes) {
ValueBuilder::appendCaseToSwitch(theSwitch,
@@ -1106,12 +1086,12 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
// the largest into
// the default by using a local and a check on the range
if (!emittedTargets.count(curr->default_)) {
+ stopFurtherFallthrough();
ValueBuilder::appendDefaultToSwitch(theSwitch);
ValueBuilder::appendCodeToSwitch(
theSwitch, blockify(makeBreakOrContinue(curr->default_)), false);
}
return theSwitch;
-#endif
}
Ref visitCall(Call* curr) {
diff --git a/test/wasm2js/br_table_hoisting.2asm.js b/test/wasm2js/br_table_hoisting.2asm.js
index e1d743cfe..8d5e45440 100644
--- a/test/wasm2js/br_table_hoisting.2asm.js
+++ b/test/wasm2js/br_table_hoisting.2asm.js
@@ -104,6 +104,7 @@ function asmFunc(global, env, buffer) {
}
zed(-1 | 0);
zed(-2 | 0);
+ break;
case 0:
break a;
case 1:
diff --git a/test/wasm2js/br_table_hoisting.2asm.js.opt b/test/wasm2js/br_table_hoisting.2asm.js.opt
index 44c9d0417..f28214760 100644
--- a/test/wasm2js/br_table_hoisting.2asm.js.opt
+++ b/test/wasm2js/br_table_hoisting.2asm.js.opt
@@ -100,6 +100,7 @@ function asmFunc(global, env, buffer) {
}
zed(-1);
zed(-2);
+ break;
case 0:
break a;
case 1:
@@ -140,6 +141,7 @@ function asmFunc(global, env, buffer) {
}
zed(-1);
zed(-2);
+ break;
case 0:
break a;
case 1:
diff --git a/test/wasm2js/br_table_temp.2asm.js.opt b/test/wasm2js/br_table_temp.2asm.js.opt
index bc29f2c3a..eba815912 100644
--- a/test/wasm2js/br_table_temp.2asm.js.opt
+++ b/test/wasm2js/br_table_temp.2asm.js.opt
@@ -12571,6 +12571,7 @@ function asmFunc(global, env, buffer) {
$2 = 18;
case 1:
$1 = $2 + 1 | 0;
+ break;
default:
break block;
};
@@ -12589,6 +12590,7 @@ function asmFunc(global, env, buffer) {
$2 = 16;
case 1:
$1 = $2 + 1 | 0;
+ break;
case 0:
break block;
};
@@ -12607,6 +12609,7 @@ function asmFunc(global, env, buffer) {
$2 = 16;
case 1:
$1 = $2 + 1 | 0;
+ break;
default:
break block;
};
diff --git a/test/wasm2js/excess_fallthrough.2asm.js b/test/wasm2js/excess_fallthrough.2asm.js
new file mode 100644
index 000000000..e5c4bcd1a
--- /dev/null
+++ b/test/wasm2js/excess_fallthrough.2asm.js
@@ -0,0 +1,55 @@
+
+function asmFunc(global, env, buffer) {
+ var HEAP8 = new global.Int8Array(buffer);
+ var HEAP16 = new global.Int16Array(buffer);
+ var HEAP32 = new global.Int32Array(buffer);
+ var HEAPU8 = new global.Uint8Array(buffer);
+ var HEAPU16 = new global.Uint16Array(buffer);
+ var HEAPU32 = new global.Uint32Array(buffer);
+ var HEAPF32 = new global.Float32Array(buffer);
+ var HEAPF64 = new global.Float64Array(buffer);
+ var Math_imul = global.Math.imul;
+ var Math_fround = global.Math.fround;
+ var Math_abs = global.Math.abs;
+ var Math_clz32 = global.Math.clz32;
+ var Math_min = global.Math.min;
+ var Math_max = global.Math.max;
+ var Math_floor = global.Math.floor;
+ var Math_ceil = global.Math.ceil;
+ var Math_sqrt = global.Math.sqrt;
+ var abort = env.abort;
+ var nan = global.NaN;
+ var infinity = global.Infinity;
+ function bar() {
+
+ }
+
+ function foo($0) {
+ $0 = $0 | 0;
+ label$4 : while (1) {
+ label$5 : {
+ bar();
+ block : {
+ switch (123 | 0) {
+ case 0:
+ bar();
+ break;
+ default:
+ break label$5;
+ };
+ }
+ return;
+ }
+ abort();
+ };
+ }
+
+ var FUNCTION_TABLE = [];
+ return {
+ "foo": foo
+ };
+}
+
+var memasmFunc = new ArrayBuffer(65536);
+var retasmFunc = asmFunc({Math,Int8Array,Uint8Array,Int16Array,Uint16Array,Int32Array,Uint32Array,Float32Array,Float64Array,NaN,Infinity}, {abort:function() { throw new Error('abort'); }},memasmFunc);
+export var foo = retasmFunc.foo;
diff --git a/test/wasm2js/excess_fallthrough.2asm.js.opt b/test/wasm2js/excess_fallthrough.2asm.js.opt
new file mode 100644
index 000000000..a805107be
--- /dev/null
+++ b/test/wasm2js/excess_fallthrough.2asm.js.opt
@@ -0,0 +1,36 @@
+
+function asmFunc(global, env, buffer) {
+ var HEAP8 = new global.Int8Array(buffer);
+ var HEAP16 = new global.Int16Array(buffer);
+ var HEAP32 = new global.Int32Array(buffer);
+ var HEAPU8 = new global.Uint8Array(buffer);
+ var HEAPU16 = new global.Uint16Array(buffer);
+ var HEAPU32 = new global.Uint32Array(buffer);
+ var HEAPF32 = new global.Float32Array(buffer);
+ var HEAPF64 = new global.Float64Array(buffer);
+ var Math_imul = global.Math.imul;
+ var Math_fround = global.Math.fround;
+ var Math_abs = global.Math.abs;
+ var Math_clz32 = global.Math.clz32;
+ var Math_min = global.Math.min;
+ var Math_max = global.Math.max;
+ var Math_floor = global.Math.floor;
+ var Math_ceil = global.Math.ceil;
+ var Math_sqrt = global.Math.sqrt;
+ var abort = env.abort;
+ var nan = global.NaN;
+ var infinity = global.Infinity;
+ function foo($0) {
+ $0 = $0 | 0;
+ abort();
+ }
+
+ var FUNCTION_TABLE = [];
+ return {
+ "foo": foo
+ };
+}
+
+var memasmFunc = new ArrayBuffer(65536);
+var retasmFunc = asmFunc({Math,Int8Array,Uint8Array,Int16Array,Uint16Array,Int32Array,Uint32Array,Float32Array,Float64Array,NaN,Infinity}, {abort:function() { throw new Error('abort'); }},memasmFunc);
+export var foo = retasmFunc.foo;
diff --git a/test/wasm2js/excess_fallthrough.wast b/test/wasm2js/excess_fallthrough.wast
new file mode 100644
index 000000000..a31ba88f3
--- /dev/null
+++ b/test/wasm2js/excess_fallthrough.wast
@@ -0,0 +1,21 @@
+(module
+ (export "foo" (func $foo))
+ (func $bar)
+ (func $foo (param $0 i32)
+ (loop $label$4
+ (block $label$5
+ (call $bar)
+ (block
+ (block $label$7
+ (br_table $label$7 $label$5
+ (i32.const 123)
+ )
+ )
+ (call $bar)
+ )
+ (return)
+ )
+ (unreachable)
+ )
+ )
+)
diff --git a/test/wasm2js/switch.2asm.js b/test/wasm2js/switch.2asm.js
index b7583298e..3c2572315 100644
--- a/test/wasm2js/switch.2asm.js
+++ b/test/wasm2js/switch.2asm.js
@@ -46,6 +46,7 @@ function asmFunc(global, env, buffer) {
j = 101;
default:
j = 102;
+ break;
case 7:
break $7;
};
generated by cgit v1.2.3 (git 2.39.1) at 2025-08-05 21:06:50 +0000