0a1,107
> From 1484f4a4f5a04a83738e6616b926a472d23b8adf Mon Sep 17 00:00:00 2001
> From: Peter Zhu <peter@peterzhu.ca>
> Date: Tue, 14 Jun 2022 14:37:21 -0400
> Subject: [PATCH] Define the GC compaction support during run time.
> 
> == Summary of the implementation ==
> 
> The patch is created by 3 commits on the upstream Ruby master branch in
> the chronological order below.
> https://github.com/ruby/ruby/commit/52d42e702375446746164a0251e1a10bce813b78
> https://github.com/ruby/ruby/commit/79eaaf2d0b641710613f16525e4b4c439dfe854e
> https://github.com/ruby/ruby/commit/2c190863239bee3f54cfb74b16bb6ea4cae6ed20
> 
> The implementation is basically to replace the wrongly used
> `GC_COMPACTION_SUPPORTED` with the `GC_CAN_COMPILE_COMPACTION`.
> 
> * GC_COMPACTION_SUPPORTED macro
>   only checks whether compaction is supported at compile time.
> * GC_CAN_COMPILE_COMPACTION macro
>   checks whether compaction is supported at both compile and run time.
> 
> == How to create this patch ==
> 
> Download Ruby source code.
> ```
> $ git clone https://github.com/ruby/ruby.git
> $ cd ruby
> ```
> 
> First create a commit squashed from the 3 commits above.
> Checkout the second commmit above, and create a temporary branch.
> ```
> $ git checkout 79eaaf2d0b641710613f16525e4b4c439dfe854e
> $ git checkout -b wip/detect-compaction-runtime-tmp
> ```
> 
> Cherry pick the third commit on the second commit.
> ```
> $ git cherry-pick 2c190863239bee3f54cfb74b16bb6ea4cae6ed20
> ```
> 
> Squash the last 3 commits on the branch.
> ```
> $ git rebase -i 2223eb082afa6d05321b69df783d4133b9aacba6
> ```
> 
> Then checkout Ruby 3.1.2 branch.
> Create a new branch.
> Merge the Fedora Ruby's ruby-3.2.0-define-unsupported-gc-compaction-methods-as-rb_f_notimplement.patch.
> ```
> $ git checkout v3_1_2
> $ git checkout -b wip/detect-compaction-runtime
> $ patch -p1 < ~/fed/ruby/ruby-3.2.0-define-unsupported-gc-compaction-methods-as-rb_f_notimplement.patch
> $ git add gc.c gc.rb test/ruby/test_gc_compact.rb
> $ git commit
> ```
> 
> Merge the squashed on commit on the `wip/detect-compaction-runtime-tmp` branch
> into the `wip/detect-compaction-runtime` branch.
> ```
> $ git cherry-pick <the squashed commit above>
> ```
> 
> Fix conflicts seeing the difference by `git show <the squashed commit above>`
> on another terminal.
> ```
> $ vi gc.c
> $ git add gc.c
> $ git commit
> ```
> 
> == Original commit messages ==
> 
> This is a combination of 3 commits.
> This is the 1st commit message:
> ~~~
> Rename GC_COMPACTION_SUPPORTED
> 
> Naming this macro GC_COMPACTION_SUPPORTED is misleading because it
> only checks whether compaction is supported at compile time.
> 
> [Bug #18829]
> ~~~
> 
> This is the commit message #2:
> ~~~
> Include runtime checks for compaction support
> 
> Commit 0c36ba53192c5a0d245c9b626e4346a32d7d144e changed GC compaction
> methods to not be implemented when not supported. However, that commit
> only does compile time checks (which currently only checks for WASM),
> but there are additional compaction support checks during run time.
> 
> This commit changes it so that GC compaction methods aren't defined
> during run time if the platform does not support GC compaction.
> 
> [Bug #18829]
> ~~~
> 
> This is the commit message #3:
> ~~~
> Suppress code unused unless GC_CAN_COMPILE_COMPACTION
> ~~~
> ---
>  gc.c | 62 ++++++++++++++++++++++++++++++++++++++++--------------------
>  1 file changed, 42 insertions(+), 20 deletions(-)
> 
2c109
< index 1c35856c44..c80a3de365 100644
---
> index 1c35856c44..3dbb4d156b 100644
10c117
< +#if defined(__wasi__)
---
> +#if defined(__wasi__) /* WebAssembly doesn't support signals */
22c129
< +# define GC_COMPACTION_SUPPORTED (GC_CAN_COMPILE_COMPACTION && USE_MMAP_ALIGNED_ALLOC)
---
> +# define GC_COMPACTION_SUPPORTED (GC_CAN_COMPILE_COMPACTION && HEAP_PAGE_ALLOC_USE_MMAP)
97c204,206
< @@ -10816,6 +10828,7 @@ gc_set_auto_compact(VALUE _, VALUE v)
---
> @@ -10814,8 +10826,7 @@ gc_disable(rb_execution_context_t *ec, VALUE _)
>  static VALUE
>  gc_set_auto_compact(VALUE _, VALUE v)
99,100c208,209
<      /* If not MinGW, Windows, or does not have mmap, we cannot use mprotect for
<       * the read barrier, so we must disable automatic compaction. */
---
> -    /* If not MinGW, Windows, or does not have mmap, we cannot use mprotect for
> -     * the read barrier, so we must disable automatic compaction. */
105c214
< @@ -10824,7 +10837,8 @@ gc_set_auto_compact(VALUE _, VALUE v)
---
> @@ -10824,7 +10835,7 @@ gc_set_auto_compact(VALUE _, VALUE v)
110d218
< +
115c223
< @@ -13696,11 +13710,20 @@ Init_GC(void)
---
> @@ -13696,11 +13707,21 @@ Init_GC(void)
123a232
> +
129,130c238,239
< +        rb_define_singleton_method(rb_mGC, "verify_compaction_references", gc_verify_compaction_references, -1);
< +    } else {
---
> +    }
> +    else {
141c250
< @@ -13724,6 +13747,7 @@ Init_GC(void)
---
> @@ -13724,6 +13745,7 @@ Init_GC(void)
145c254
< +        OPT(GC_COMPACTION_SUPPORTED);
---
> +	OPT(GC_COMPACTION_SUPPORTED);
148a258,260
> -- 
> 2.36.1
>