Remove IsCallerSPValid, standardize caller-frame validity on IsCallerContextValid, and finalize AsmOffsets updates

[Copilot]

IsCallerSPValid was a legacy EH-era flag that could drift from IsCallerContextValid semantics. This change removes the legacy flag and makes caller-frame validity uniformly context-based, with explicit callouts for spots that previously tolerated divergence.

• Description

  • Removed IsCallerSPValid from REGDISPLAY_BASE.
  • Replaced remaining checks/preconditions with IsCallerContextValid.
  • Deleted all IsCallerSPValid writes in unwind/update paths across CoreCLR VM and debugger architecture-specific code.
  • Updated src/coreclr/System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs for affected 32-bit targets (ARM, X86, WASM) so REGDISPLAY size/offset constants match the new layout and native static asserts pass.
  • Follow-up fix: corrected TARGET_ARM Release REGDISPLAY constants in AsmOffsets.cs to match the current native layout (SIZEOF__REGDISPLAY, OFFSETOF__REGDISPLAY__SP, OFFSETOF__REGDISPLAY__ControlPC) after CI-reported ARM static-assert mismatches.

• Key change areas

  • src/coreclr/inc/regdisp.h
  • src/coreclr/inc/stackframe.h
  • src/coreclr/vm/exceptionhandling.cpp
  • src/coreclr/vm/eetwain.cpp
  • architecture/debugger unwind/update sites that previously assigned both flags
  • src/coreclr/System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs

• Manual inspection callouts (safety review)

  • src/coreclr/vm/eetwain.cpp (EnsureCallerContextIsValid paths)
  • src/coreclr/vm/stackwalk.cpp (StackFrameIterator::SkipTo)
  • src/coreclr/gcinfo/gcinfodumper.cpp (synthetic REGDISPLAY initialization)

• Example

  // Before
  _ASSERTE(pRD->IsCallerSPValid || pRD->IsCallerContextValid);
  
  // After
  _ASSERTE(pRD->IsCallerContextValid);

• Validation

  • ./build.sh clr.runtime -c Release -arch x64 -os linux -ninja
  • ./build.sh clr.runtime -os browser -arch wasm -c Release -ninja
  • ./build.sh clr.runtime -c Release -arch arm -os linux -ninja

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[davidwrighton]

@copilot, in the build there are a lot of errors that look like

  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:261:19: error: static assertion failed due to requirement 'sizeof(REGDISPLAY) == AsmOffsets::SIZEOF__REGDISPLAY'
    261 |     static_assert(sizeof(REGDISPLAY) == AsmOffsets::SIZEOF__REGDISPLAY);
        |                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:261:38: note: expression evaluates to '80 == 84'
    261 |     static_assert(sizeof(REGDISPLAY) == AsmOffsets::SIZEOF__REGDISPLAY);
        |                   ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:262:19: error: static assertion failed due to requirement '__builtin_offsetof(REGDISPLAY, SP) == AsmOffsets::OFFSETOF__REGDISPLAY__SP'
    262 |     static_assert(offsetof(REGDISPLAY, SP) == AsmOffsets::OFFSETOF__REGDISPLAY__SP);
        |                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /__w/1/s/src/mono/browser/emsdk/lib/clang/19/include/__stddef_offsetof.h:16:24: note: expanded from macro 'offsetof'
     16 | #define offsetof(t, d) __builtin_offsetof(t, d)
        |                        ^
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:262:44: note: expression evaluates to '72 == 76'
    262 |     static_assert(offsetof(REGDISPLAY, SP) == AsmOffsets::OFFSETOF__REGDISPLAY__SP);
        |                   ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:263:19: error: static assertion failed due to requirement '__builtin_offsetof(REGDISPLAY, ControlPC) == AsmOffsets::OFFSETOF__REGDISPLAY__ControlPC'
    263 |     static_assert(offsetof(REGDISPLAY, ControlPC) == AsmOffsets::OFFSETOF__REGDISPLAY__ControlPC);
        |                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /__w/1/s/src/mono/browser/emsdk/lib/clang/19/include/__stddef_offsetof.h:16:24: note: expanded from macro 'offsetof'
     16 | #define offsetof(t, d) __builtin_offsetof(t, d)
        |                        ^
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:263:51: note: expression evaluates to '76 == 80'
    263 |     static_assert(offsetof(REGDISPLAY, ControlPC) == AsmOffsets::OFFSETOF__REGDISPLAY__ControlPC);
    
    ```
    
    These are different on each platform, but generally indicate that offsets and sizes need to be fixed. Please do so.

[Copilot]

@copilot, in the build there are a lot of errors that look like

  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:261:19: error: static asser...

Fixed in 87ea2d9 by updating src/coreclr/System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs to match the new REGDISPLAY layout after removing IsCallerSPValid.

I updated the SIZEOF__REGDISPLAY, OFFSETOF__REGDISPLAY__SP, and OFFSETOF__REGDISPLAY__ControlPC constants for the affected 32-bit targets (ARM, X86, WASM) in both Debug and Release sections.

Validated with:

• ./build.sh clr.runtime -c Release -arch x64 -os linux -ninja
• ./build.sh clr.runtime -os browser -arch wasm -c Release -ninja

[davidwrighton]

@copilot arm builds are still failing with errors like

1300/2198] Building CXX object vm/wks/CMakeFiles/cee_wks_core.dir/__/exceptionhandling.cpp.o
  FAILED: vm/wks/CMakeFiles/cee_wks_core.dir/__/exceptionhandling.cpp.o 
  /usr/local/bin/clang++ --target=armv7-alpine-linux-musleabihf --gcc-toolchain=/crossrootfs/arm/usr --sysroot=/crossrootfs/arm -DCLR_ARM_FPU_CAPABILITY=0x7 -DCOMPILER_SUPPORTS_W_RESERVED_IDENTIFIER -DDEBUGGING_SUPPORTED -DDISABLE_CONTRACTS -DFEATURE_BASICFREEZE -DFEATURE_CODE_VERSIONING -DFEATURE_COLLECTIBLE_TYPES -DFEATURE_COMWRAPPERS -DFEATURE_CORECLR -DFEATURE_CORECLR_FLUSH_INSTRUCTION_CACHE_TO_PROTECT_STUB_READS -DFEATURE_DBGIPC_TRANSPORT_DI -DFEATURE_DBGIPC_TRANSPORT_VM -DFEATURE_DEFAULT_INTERFACES -DFEATURE_DYNAMIC_CODE_COMPILED -DFEATURE_EMULATE_SINGLESTEP -DFEATURE_EVENTSOURCE_XPLAT -DFEATURE_EVENT_TRACE -DFEATURE_HIJACK -DFEATURE_METADATA_UPDATER -DFEATURE_MULTICOREJIT -DFEATURE_MULTITHREADING -DFEATURE_PAL_ANSI -DFEATURE_PERFMAP -DFEATURE_PERFTRACING -DFEATURE_PGO -DFEATURE_PROFAPI_ATTACH_DETACH -DFEATURE_READYTORUN -DFEATURE_REJIT -DFEATURE_REMOTE_PROC_MEM -DFEATURE_STANDALONE_GC -DFEATURE_SVR_GC -DFEATURE_SYMDIFF -DFEATURE_TIERED_COMPILATION -DFEATURE_USE_ASM_GC_WRITE_BARRIERS -DFEATURE_USE_SOFTWARE_WRITE_WATCH_FOR_GC_HEAP -DFEATURE_VIRTUAL_STUB_DISPATCH -DGC_DESCRIPTOR -DHOST_ARM -DHOST_UNIX -DNDEBUG -DNO_FIXED_STACK_LIMIT -DPROFILING_SUPPORTED -DTARGET_32BIT -DTARGET_ARM -DTARGET_LINUX -DTARGET_LINUX_MUSL -DTARGET_UNIX -DUNICODE -DUNIX_ARM_ABI -DURTBLDENV_FRIENDLY=Retail -D_FILE_OFFSET_BITS=64 -D_SECURE_SCL=0 -D_TIME_BITS=64 -D_UNICODE -I/__w/1/s/artifacts/obj/coreclr/linux.arm.Release/vm/wks -I/__w/1/s/src/coreclr/vm/wks -I/__w/1/s/src/coreclr/vm -I/__w/1/s/src/native -I/__w/1/s/src/native/inc -I/__w/1/s/src/coreclr/pal/prebuilt/inc -I/__w/1/s/artifacts/obj -I/__w/1/s/src/coreclr/pal/inc -I/__w/1/s/src/coreclr/pal/inc/rt -I/__w/1/s/src/coreclr/pal/src/safecrt -I/__w/1/s/src/coreclr/inc -I/__w/1/s/src/coreclr/debug/inc -I/__w/1/s/src/coreclr/debug/inc/arm -I/__w/1/s/src/coreclr/debug/inc/dump -I/__w/1/s/src/coreclr/md/inc -I/__w/1/s/artifacts/obj/coreclr/linux.arm.Release/inc -I/__w/1/s/src/coreclr/hosts/inc -I/__w/1/s/src/coreclr/interpreter/inc -I/__w/1/s/src/coreclr/minipal -I/__w/1/s/src/coreclr/nativeresources -I/__w/1/s/src/coreclr/vm/arm -I/__w/1/s/src/coreclr/vm/../interop/inc -I/__w/1/s/src/coreclr/runtime -I/__w/1/s/src/native/libs/System.IO.Compression.Native -I/__w/1/s/src/native/libs/Common -I/__w/1/s/src/coreclr/vm/eventing/eventpipe -O3 -DNDEBUG -std=gnu++17 -fPIC -mthumb -mfpu=vfpv3 -O3 -Wall -Wno-null-conversion -glldb -fno-omit-frame-pointer -fno-strict-overflow -fno-strict-aliasing -fstack-protector-strong -Werror -Wno-unused-variable -Wno-unused-value -Wno-unused-function -Wno-tautological-compare -Wno-unknown-pragmas -Wimplicit-fallthrough -Wvla -Wno-invalid-offsetof -Wno-unused-but-set-variable -ffp-contract=off -fno-rtti -Wno-unknown-warning-option -ferror-limit=4096 -Wno-unused-private-field -Wno-constant-logical-operand -Wno-pragma-pack -Wno-incompatible-ms-struct -Wno-reserved-identifier -Wno-unsafe-buffer-usage -Wno-single-bit-bitfield-constant-conversion -Wno-cast-function-type-strict -Wno-switch-default -Wno-nontrivial-memaccess -fsigned-char -fvisibility=hidden -ffunction-sections -fdata-sections -march=armv7-a -Wno-null-arithmetic -Wno-sync-alignment -Winvalid-pch -Xclang -include-pch -Xclang /__w/1/s/artifacts/obj/coreclr/linux.arm.Release/vm/wks/CMakeFiles/cee_wks_core.dir/cmake_pch.hxx.pch -Xclang -include -Xclang /__w/1/s/artifacts/obj/coreclr/linux.arm.Release/vm/wks/CMakeFiles/cee_wks_core.dir/cmake_pch.hxx -MD -MT vm/wks/CMakeFiles/cee_wks_core.dir/__/exceptionhandling.cpp.o -MF vm/wks/CMakeFiles/cee_wks_core.dir/__/exceptionhandling.cpp.o.d -o vm/wks/CMakeFiles/cee_wks_core.dir/__/exceptionhandling.cpp.o -c /__w/1/s/src/coreclr/vm/exceptionhandling.cpp
  In file included from /__w/1/s/src/coreclr/vm/exceptionhandling.cpp:4469:
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:261:19: error: static assertion failed due to requirement 'sizeof(REGDISPLAY) == AsmOffsetsAsserts::AsmOffsets::SIZEOF__REGDISPLAY'
    261 |     static_assert(sizeof(REGDISPLAY) == AsmOffsets::SIZEOF__REGDISPLAY);
        |                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:261:38: note: expression evaluates to '1024 == 1028'
    261 |     static_assert(sizeof(REGDISPLAY) == AsmOffsets::SIZEOF__REGDISPLAY);
        |                   ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:262:19: error: static assertion failed due to requirement '__builtin_offsetof(REGDISPLAY, SP) == AsmOffsetsAsserts::AsmOffsets::OFFSETOF__REGDISPLAY__SP'
    262 |     static_assert(offsetof(REGDISPLAY, SP) == AsmOffsets::OFFSETOF__REGDISPLAY__SP);
        |                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /crossrootfs/arm/usr/include/stddef.h:22:32: note: expanded from macro 'offsetof'
     22 | #define offsetof(type, member) __builtin_offsetof(type, member)
        |                                ^
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:262:44: note: expression evaluates to '992 == 996'
    262 |     static_assert(offsetof(REGDISPLAY, SP) == AsmOffsets::OFFSETOF__REGDISPLAY__SP);
        |                   ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:263:19: error: static assertion failed due to requirement '__builtin_offsetof(REGDISPLAY, ControlPC) == AsmOffsetsAsserts::AsmOffsets::OFFSETOF__REGDISPLAY__ControlPC'
    263 |     static_assert(offsetof(REGDISPLAY, ControlPC) == AsmOffsets::OFFSETOF__REGDISPLAY__ControlPC);
        |                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /crossrootfs/arm/usr/include/stddef.h:22:32: note: expanded from macro 'offsetof'
     22 | #define offsetof(type, member) __builtin_offsetof(type, member)
        |                                ^
  /__w/1/s/src/coreclr/vm/../System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs:263:51: note: expression evaluates to '996 == 1000'
    263 |     static_assert(offsetof(REGDISPLAY, ControlPC) == AsmOffsets::OFFSETOF__REGDISPLAY__ControlPC);
        |

[Copilot]

@copilot arm builds are still failing with errors like

Fixed in b85338d9.

I corrected the ARM Release AsmOffsets REGDISPLAY constants to match the native layout after removing IsCallerSPValid:

• SIZEOF__REGDISPLAY = 0x400
• OFFSETOF__REGDISPLAY__SP = 0x3e0
• OFFSETOF__REGDISPLAY__ControlPC = 0x3e4

Validation run:

• ./build.sh clr.runtime -c Release -arch arm -os linux -ninja (passes)
• ./build.sh clr.runtime -c Release -arch x64 -os linux -ninja (passes)