1592983 - Only validate WebAssembly baseline stack in live code

Status: RESOLVED FIXED

(Core :: JavaScript: WebAssembly, defect, P3)

Description

[Andy Wingo [:wingo]]

Given this test (to be committed):

wasmFullPass(`
  (module
    (func (export "run") (result i32)
      (i32.add
        (block (result i32 i32)
          (i32.const 32)
          (i32.const 10)
          (br 0)))))`,
             42);

After the (br 0) -- which is right before the i32.add, in terms of instruction flow -- the assertStackInvariants check barfed because the Stk value stack no longer corresponded to the dynamic frame height:

Assertion failure: size == fr.dynamicHeight(), at /home/wingo/src/mozilla-unified/js/src/wasm/WasmBaselineCompile.cpp:4412

This is because writing the stack args for the branch resulted in codegen reserving some stack space, but the Stk stack was only reset once the block actually ended.

I think simply avoiding the debug check in dead code might be the right thing.

Comment 1

[Andy Wingo [:wingo]]

Attachment: Bug 1592983 - Only validate WebAssembly baseline stack in live code

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/39bc5b23a7a9
Only validate WebAssembly baseline stack in live code r=lth

Comment 3

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/mozilla-central/rev/39bc5b23a7a9