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Wasm targets should append lld --stack-first #4496

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#5501
Closed
Wasm targets should append lld --stack-first#4496
#5501
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acceptedThis proposal is planned.arch-wasm32-bit and 64-bit WebAssemblycontributor friendlyThis issue is limited in scope and/or knowledge of Zig internals.proposalThis issue suggests language modifications. If it also has the "accepted" label then it is planned.
Milestone
0.7.0

Description

@fengb
fengb
opened on Feb 18, 2020

By default, LLVM adopts this memory model:

|   Globals   |   <-- Stack   |   Heap -->  |++

This means when the stack runs out of space, it will start trampling over global memory before causing a stack overflow.

Appending --stack-first will flip where the stack and the globals are located, so stack overflow will error out immediately instead of corrupting globals.

Rust has made a similar decision: rustwasm/team#81 (comment)

Activity

  1. andrewrk
    added
    arch-wasm32-bit and 64-bit WebAssembly
    proposalThis issue suggests language modifications. If it also has the "accepted" label then it is planned.
    on Feb 18, 2020
  2. andrewrk
    added this to the 0.7.0 milestone on Feb 18, 2020
  3. andrewrk
    added
    acceptedThis proposal is planned.
    contributor friendlyThis issue is limited in scope and/or knowledge of Zig internals.
    on Feb 18, 2020

  4. zigazeljko commented on May 31, 2020

    @zigazeljko
    zigazeljko
    on May 31, 2020
    Contributor

    So the only change is adding lj->args.append("--stack-first"); to construct_linker_job_wasm?

    If so, I can prepare a pull request.

  5. fengb commented on Jun 1, 2020

    @fengb
    fengb
    on Jun 1, 2020
    ContributorAuthor

    Yep that should be it.

  6. andrewrk
    closed this as completedin #5501on Jul 27, 2020
  7. jedisct1
    added 2 commits that reference this issue on Jul 28, 2020

    WASI: Put the stack before globals

    7e9095b

    WASI: Put the stack before globals

    d37afd6
  8. liujinye-sys
    added a commit that references this issue on Jul 23, 2025

    WASI: Put the stack before globals

    6d0e4b0
  9. liujinye-sys
    added a commit that references this issue on Dec 16, 2025

    WASI: Put the stack before globals

    1248bc9
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