[wasm-ld] How to specify a non-growable memory without `--initial-memory` and `--max-memory`

[sbc100]

Until recently the way to specify a non-growable memory was to specify both --initial-memory and --max-memory and set them to the same value. This is what emscripten currently does by default unless you opt into -sALLOW_MEMORY_GROWTH.

However, we recently added a new --initial-heap flag which allows the user to set and initial heap size and have the linker then derive the initial memory size based on the sum of stack size + heap size + static data size. See #75594.

When attempting to start using this flag in emscripten we discovered that there is no way to use the --initial-heap flag and still get a non-growable memory. See https://github.com/emscripten-core/emscripten/pull/21071/files#r1491731562.

It seems that we need some kind of flag like the existing --growable-table flag. It would be nice to add --growable-memory except that would mean changing the default to non-growable, which is perhaps too much of a breaking change. @sunfishcode WDYT?

Instead perhaps we can add --no-growable-memory?

Perhaps the existing --growable-table flag could also take a no- prefix so that they were symmetrical?

[llvmbot]

@llvm/issue-subscribers-lld-wasm

Author: Sam Clegg (sbc100)

Until recently the way to specify a non-growable memory was to specify both `--initial-memory` and `--max-memory` and set them to the same value. This is what emscripten currently does by default unless you opt into `-sALLOW_MEMORY_GROWTH`.

However, we recently added a new --initial-heap flag which allows the user to set and initial heap size and have the linker then derive the initial memory size based on the sum of stack size + heap size + static data size. See #75594.

When attempting to start using this flag in emscripten we discovered that there is no way to use the --initial-heap flag and still get a non-growable memory. See https://github.com/emscripten-core/emscripten/pull/21071/files#r1491731562.

It seems that we need some kind of flag like the existing --growable-table flag. It would be nice to add --growable-memory except that would mean changing the default to non-growable, which is perhaps too much of a breaking change. @sunfishcode WDYT?

Instead perhaps we can add --no-growable-memory?

Perhaps the existing --growable-table flag could also take a no- prefix so that they were symmetrical?