Feature/m0081 meja 2367 linear mem and sni review #1186
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… by its module name
Co-authored-by: agazardMicroeJ <[email protected]>
Co-authored-by: agazardMicroeJ <[email protected]>
Co-authored-by: agazardMicroeJ <[email protected]>
put back the "call" Java to C and C to Java that can be directly linked
Co-authored-by: agazardMicroeJ <[email protected]>
…tdlib linker option
frivieremicroej
commented
Jan 21, 2025
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| Given the following Wasm module: | ||
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| .. code:: wat |
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When possible, I prefer to keep managed C here instead of wat file.
how to we define the number of pages using clang ?
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| Wasm linear memory is a contiguous, byte-addressable memory region used in Wasm programs. | ||
| It is the main mechanism through which a Wasm module manages its memory and exchanges data with :ref:`the host <managedc.communication.managedc_memory>`. | ||
| This memory is represented as an array of bytes, indexed starting at zero, and is :ref:`dynamically resizable <managedc.instructions.partially_supported>`. |
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In our case this is false (see memory.grow), and maybe this is in fact a feature and we will let it as-is.
To be reworded in this direction.
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| To minimize the size of allocated memory, a Wasm module should: | ||
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| * Export the the Wasm global ``__heap_base``, using the linker option ``-Wl,--export=__heap_base`` like the following Wasm module, |
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Same, how to we reduce the page with clang ?
Is it using the clang compiler: -z stack-size=n, but in this case does it only affect the first page ?
| (export "__heap_base" (global $heap_base)) | ||
| ) | ||
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| * Avoid using the ``memory.size`` and ``memory.grow`` instructions (do not use malloc/free function in the Managed C code). |
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really ? OK maybe only for this example
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| The boundary between the auxiliary stack + the Static Data regions and the heap region is marked by the special Wasm global ``__heap_base`` | ||
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| Wasm Linear Memory Size |
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Suggested change
| Wasm Linear Memory Size | |
| Configure the Wasm Linear Memory Size |
| (export "memory" (memory $mem)) | ||
| ) | ||
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| This linear memory of this module should have an initial Size of **2 pages** (128 KiB), and a maximum Size of **10 pages** (640 KiB). |
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Suggested change
| This linear memory of this module should have an initial Size of **2 pages** (128 KiB), and a maximum Size of **10 pages** (640 KiB). | |
| This linear memory of this module should have an initial size of **2 pages** (128 KB), and a maximum Size of **10 pages** (640 KB). |
| Wasm Linear Memory Size | ||
| ----------------------- | ||
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| WebAssembly organizes linear memory in pages, where each page is **64 KiB** (65,536 bytes). |
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Suggested change
| WebAssembly organizes linear memory in pages, where each page is **64 KiB** (65,536 bytes). | |
| WebAssembly organizes linear memory in pages, where each page is **64 KB** (65,536 bytes). |
| "updated": 1736414807618, | ||
| "link": null, | ||
| "locked": false, | ||
| "text": "Grow downward", |
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Suggested change
| "text": "Grow downward", | |
| "text": "Grows downward", |
| "updated": 1736414789926, | ||
| "link": null, | ||
| "locked": false, | ||
| "text": "Grow upward", |
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Suggested change
| "text": "Grow upward", | |
| "text": "Grows upward", |
| Build Without The Standard Library | ||
| ---------------------------------- | ||
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| The ``-nostdlib`` flag is a linker option used to exclude the standard library when building a program. |
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-nostdlib is not enough
We should put back the full compilet command line here
[path_to_wasi_sdk]/bin/clang -Wl,--no-entry -Wl,--export-all -Wl,--allow-undefined -nostdlib -o my_app.wasm my_app.o
frivieremicroej
commented
Jan 22, 2025
| @@ -34,14 +36,14 @@ In the terminal, navigate to the ``src/main/c`` directory and execute the follow | |||
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| .. code:: console | |||
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| [path_to_wasi_sdk]/bin/clang -Wl,--no-entry -Wl,--export-all -Wl,--allow-undefined -nostdlib -o my_app.wasm my_app.o | |||
| [path_to_wasi_sdk]/bin/clang -Wl,--export-all -o my_app.wasm my_app.o | |||
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put back --no-entry and -Wl,--allow-undefined
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