[CoreCLR] java to managed typemap

[grendello]

This is a follow-up to #10065 (which must be merged first)

Implement an optimized (hash-based) managed-to-java typemap lookup for Debug builds, with a
fallback to string-based lookups if hash clashes are detected.

Additionally, optimize usage of certain sets of strings in native code, namely type and assembly names. Instead of storing them as "standard" string pointers, they are now contained in "blobs" - arrays of character data, separated with NUL characters. This approach gets rid of a potentially large number of native code relocations (each string is a pointer), replacing X pointers with a single pointer + offset when accessing a string. It also has a
side effect of (slightly) reducing generated code size.

[Copilot]

Pull Request Overview

This PR implements an optimized, hash‐based managed-to‐java typemap lookup for Debug builds while also optimizing the storage of type and assembly names by switching from pointer arrays to string blobs. Key updates include:

• Reordering of timing/logging checks in the native runtime initialization.
• Adoption of templated hash functions and updated binary search operations.
• Significant changes to TypeMap structures and associated C# generators for improved efficiency and reduced relocations.

Reviewed Changes

Copilot reviewed 19 out of 21 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/native/common/runtime-base/timing-internal.cc	Reordered the immediate_logging check to restrict option processing when immediate logging is enabled.
src/native/common/include/shared/xxhash.hh	Replaced a char*-based hash function with a templated version for broader applicability.
src/native/clr/include/xamarin-app.hh	Updated TypeMapEntry and related structures to use offset-based fields and std::string_view for string blobs.
src/native/clr/host/typemap.cc	Modified typemap lookup functions (debug and release) to support hash-based and string-based matching.
src/Xamarin.Android.Build.Tasks/Utilities/*.cs	Revised type mapping generators to generate and reference additional string length and offset fields.
src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Utilities/DeviceTest.cs	Updated test utilities to support new parameters for environment variable injection.

Files not reviewed (2)

• src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets: Language not supported
• src/native/native.targets: Language not supported

Comments suppressed due to low confidence (4)

src/native/common/include/shared/xxhash.hh:166

• Ensure that the updated templated hash function is compatible with existing code that depends on hash(const char*, size_t), particularly regarding type inference.

template<typename T> [[gnu::always_inline]] static auto hash (const T *p, size_t len) noexcept -> XXH64_hash_t

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Utilities/DeviceTest.cs:211

• [nitpick] Ensure that the new 'environmentVariables' parameter is adequately tested across different project run scenarios to confirm expected behavior.

protected static void RunProjectAndAssert (XamarinAndroidApplicationProject proj, ProjectBuilder builder, string logName = "run.log", Dictionary<string, string> environmentVariables = null, bool doNotCleanupOnUpdate = false, string [] parameters = null)

src/native/common/runtime-base/timing-internal.cc:30

• The reordering of the 'if (immediate_logging)' check may change the timing of when immediate logging is bypassed; please verify that this modification maintains the intended behavior.

if (immediate_logging) {

src/native/clr/include/xamarin-app.hh:66

• Changing 'from' from a pointer to a uint32_t offset requires thorough validation against all consumers of TypeMapEntry to avoid misinterpretation of data.

const uint32_t from;

[grendello]

/azp run

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