[CoreCLR] Complete in-process crash reporter support for community platforms #131535

Summary

#131410 enabled CoreCLR's in-process crash reporter on Android, Apple, and Linux targets. Other native Unix ports remain excluded because the reporter currently assumes Linux or Darwin signal-context headers and layouts.

Community Linux architectures

The reporter currently recognizes and extracts signal context for x64, x86, ARM64, and ARM.

The remaining community Linux architectures include:

• linux-riscv64
• linux-loongarch64
• linux-ppc64le
• linux-s390x

Proposed work

• Add the correct architecture name.
• Extract IP, SP, and BP from the Linux ucontext_t layout.
• Validate register mappings against the platform ABI and existing PAL context handling.
• Build using the repository's cross-build infrastructure.
• Where a runnable CoreCLR port exists, trigger a fatal crash and validate the console and JSON reports end to end.

Community Unix operating systems

The reporter is not currently compiled or enabled for community Unix targets such as:

• FreeBSD
• OpenBSD
• Haiku
• NetBSD
• illumos

src/coreclr/debug/crashreport/inproccrashreporter.cpp currently assumes Linux or Darwin signal-context headers and layouts. These operating systems expose ucontext_t and saved registers through different headers and fields.

For example, OpenBSD and Haiku require <signal.h> rather than <ucontext.h> for the relevant context definitions. FreeBSD, OpenBSD, NetBSD, and Haiku also use different fields for IP, SP, and BP.

Proposed work

• Select the appropriate signal-context header for each operating system.
• Add OS- and architecture-specific IP, SP, and BP extraction.
• Extend the FEATURE_INPROC_CRASHREPORT platform gate after the reporter compiles successfully.
• Cross-build CoreCLR using the repository's community-platform infrastructure.
• Where possible, trigger a fatal crash and validate the console and JSON reports end to end.

Exploratory validation

An experimental port established the following:

• FreeBSD x64 completed a full clr.runtime cross-build after adding its context layout.
• OpenBSD x64 completed a full clr.runtime cross-build after selecting <signal.h> and adding its context layout.
• The Haiku reporter target compiled after selecting <signal.h> and adding its context layout. The broader runtime build encountered unrelated existing corehost failures.
• NetBSD and illumos were not validated because suitable current cross-build environments were unavailable.

These experimental changes were not included in #131410.

Out of scope

• Windows, which requires a different native crash-context implementation.
• Browser and WASI, which do not provide the required native fatal-signal process model.