[FMV] Add support-level table and remove __ARM_ACLE_VERSION

Remove __ARM_ACLE_VERSION, change __ARM_ACLE to represent when the header is
available, and update __FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL so that it
refers to a new Function Multi Versioning feature availability table.

For backwards compatibility with previous features, the table lists the support
level at which each current FMV target version name became available. It also
defines how future FMV feature sets allocate new support levels.

Author: CarolineConcatto

main/acle.md

@@ -1499,32 +1499,8 @@ enclose them in parentheses if they are not simple constants.
 
 ## Testing for Arm C Language Extensions
 
-`__ARM_ACLE` is defined as the version of this specification that is
-implemented, formatted as `{YEAR}{QUARTER}{PATCH}`. The `YEAR` segment is
-composed of 4 digits, the `QUARTER` segment is composed of 1 digit, and
-the `PATCH` segment is also composed of 1 digit.
-
-For example:
-
- - An implementation based on the version 2023 Q2 of the ACLE with no
-   further patch releases will define `__ARM_ACLE` as `202320`.
- - An implementation based on a hypothetical version 2024 Q3 of the ACLE
-   with two patch releases will define `__ARM_ACLE` as `202432`.
-
-NOTE: Previously, the macro followed the previous versioning scheme and
-was defined as `100 * major_version + minor_version`, which was the
-version of this specification implemented. For instance, an implementation
-implementing version 2.1 of the ACLE specification defined `__ARM_ACLE`
-as `201`.
-
-`__ARM_ACLE_VERSION(year, quarter, patch)` is defined to express a given
-ACLE version. Returns with the version number in the same format as the
-`__ARM_ACLE` does. Checking the minimum required ACLE version could be
-written as:
-
-``` c
-#if __ARM_ACLE >= __ARM_ACLE_VERSION(2024, 1, 0)
-```
+An implementation that supports the Arm C Language Extensions defines `__ARM_ACLE`.
+For compatibility with existing code, the recommended value of this macro is `202420`.
 
 ## Endianness
 
@@ -2998,14 +2974,8 @@ following:
 versioning mechanism described in this section is supported by the
 compiler and it is enabled.
 
-`__FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL` is defined to the currently supported
-version of the ACLE. The value and the format are the same as the `__ARM_ACLE`.
-
-For example, it can be implemented as:
-
-``` c
-#define __FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL __ARM_ACLE_VERSION(2024, 3, 0)
-```
+`__FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL` is defined as a value corresponding to the
+support level listed in [Function Multi Versioning feature availability](#function-multi-versioning-feature-availability).
 
 ### Target version strings
 
@@ -3130,6 +3100,71 @@ The following table lists the architectures feature mapping for AArch64.
 
 The tables are sorted by priority, starting from features of lowest priority ending with features of highest priority.
 
+### Function Multi Versioning feature availability
+
+The following table lists the Function Multi Versioning support level at
+which each target version name became available.
+
+A Function Multi Versioning target version name is supported when
+`__HAVE_FUNCTION_MULTI_VERSIONING` is defined to `1` and
+`__FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL` is greater than or equal to
+the support level listed for that name. Support for a given support level
+includes all target version names introduced at earlier support levels,
+unless otherwise specified.
+
+
+   | **Name**      | **Minimum support level** |
+   | ------------- | ------------------------- |
+   | default       | **202210**                |
+   | sha1          | 202210                    |
+   | aes           | 202210                    |
+   | vmull         | 202210                    |
+   | rng           | 202210                    |
+   | flagm         | 202210                    |
+   | flagm2        | 202210                    |
+   | lse           | 202210                    |
+   | dotprod       | 202210                    |
+   | rdm           | 202210                    |
+   | fp16          | 202210                    |
+   | dit           | 202210                    |
+   | dpb           | 202210                    |
+   | dpb2          | 202210                    |
+   | jscvt         | 202210                    |
+   | fcma          | 202210                    |
+   | frintts       | 202210                    |
+   | sve           | 202210                    |
+   | sve2          | 202210                    |
+   | sme           | 202210                    |
+   | sb            | 202210                    |
+   | ssbs          | 202210                    |
+   | bti           | 202210                    |
+   | crc           | **202240**                |
+   | sha2          | 202240                    |
+   | fp            | 202240                    |
+   | simd          | 202240                    |
+   | sm4           | 202240                    |
+   | sha3          | 202240                    |
+   | fp16fml       | 202240                    |
+   | rcpc          | 202240                    |
+   | rcpc2         | 202240                    |
+   | i8mm          | 202240                    |
+   | bf16          | 202240                    |
+   | f32mm         | 202240                    |
+   | f64mm         | 202240                    |
+   | sve2-aes      | 202240                    |
+   | sve2-bitperm  | 202240                    |
+   | sve2-sha3     | 202240                    |
+   | sve2-sm4      | 202240                    |
+   | memtag        | 202240                    |
+   | wfxt          | 202240                    |
+   | sme2          | 202240                    |
+   | rcpc3         | **202320**                |
+   | sme-f64f64    | 202320                    |
+   | sme-i16i64    | 202320                    |
+   | rdma          | **202410**                |
+   | mops          | 202410                    |
+   | cssc          | **202520**                |
+
 ### Dependencies
 
 If a feature depends on another feature as defined by the following table then: