[mono] AOT-compile methods that use the IL jmp opcode#129708
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The IL `jmp` opcode (CEE_JMP) is compiled to a real tail call (OP_TAILCALL) on the non-llvm_only path, which disables AOT for the whole method (DISABLE_AOT). Under full-AOT (aot-only) the method is then left out of the AOT image, so the first call to it fails at runtime with "Attempting to JIT compile method ... while running in aot-only mode". The llvm_only path already avoids this by emitting `jmp` as a normal call followed by a return. Extend that to AOT compilation: when compiling for AOT, emit the jmp as a call + return instead of a real tail call, so the method can be AOT compiled. This is observably equivalent for jmp (transfer to the target with the current arguments and return its result); it just does not reuse the caller's stack frame. The JIT keeps the real tail call. Fixes the Mono full-AOT failures of the JIT/jit64/localloc/call/call05_large and call05_small tests, which were crashing with ExecutionEngineException under full-AOT because their `jmp` method was excluded from the AOT image.
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Pull request overview
This PR updates Mono’s IL CEE_JMP handling during AOT compilation so methods containing jmp are no longer excluded from the AOT image (avoiding aot-only/full-AOT runtime failures due to missing compiled methods).
Changes:
- Treat
CEE_JMPas “call + return” whencfg->compile_aot(in addition to the existingcfg->llvm_onlyhandling), instead of emitting a realOP_TAILCALLthat triggersDISABLE_AOT(cfg). - Ensure the AOT path emits a plain call (non-tailcall) so it remains AOT-able by both LLVM and Mono code generators.
These tests use the IL jmp opcode from a method that also uses localloc; with the AOT compiler now emitting such methods, they pass under Mono full-AOT. Remove the ActiveIssue annotation so CI exercises the fix.
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pavelsavara
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Jun 22, 2026
Re-link the disabled Mono full-AOT tests from the #129508 tracking issue to the individual PRs that fix them (nullabletypes -> #129702, call05_large/small -> #129708, WPF_3226 -> #129710, b143840 -> #129713, UnitTest_GVM_TypeLoadException -> #129715). The tests stay disabled; Runtime_105619 keeps the #129508 link.
test_5_jmp was tagged !FULLAOT because jmp could not be AOT-compiled; this PR fixes that, so run it under full-AOT for regression coverage. Also soften the lowering comment: emitting jmp as call+return is not a true tailcall (it adds a stack frame, so stack traces can differ).
pavelsavara
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Jun 23, 2026
…ine jmp comment, fix marshalable typo Integrates the minor review follow-ups from dotnet#129708 and dotnet#129710.
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lewing
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/ba-g unrelated failures |
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Summary
Methods that use the IL
jmpopcode (CEE_JMP) are excluded from the AOT image on Mono and crash at runtime under full-AOT.Root cause
In the
CEE_JMPhandler, the non-llvm_onlypath compilesjmpto a real tail call (OP_TAILCALL) and callsDISABLE_AOT(cfg). Under full-AOT (aot-only) the method is then absent from the AOT image, so the first call to it fails with:(JIT mode is fine ΓÇö a real tail call works there.)
The
llvm_onlypath already avoids this by emittingjmpas a normal call followed by a return.Fix
Extend the
llvm_onlycall+return handling to AOT compilation (cfg->llvm_only || cfg->compile_aot). For the non-llvm_onlyAOT case the call is emitted as a plain call (tailcall = FALSE), which is AOT-able by both the LLVM and the Mono code generators. This is observably equivalent forjmpΓÇö transfer to the target with the current arguments and return its result ΓÇö it just does not reuse the caller's stack frame. The JIT keeps the real tail call.Validation
Built Mono + LLVM full-AOT on x64 and ran
JIT/jit64/localloc/call/call05_largeandcall05_small(localloc +jmp):ExecutionEngineExceptionunder full-AOT (thejmpmethodfunc0was missing from the image; only a PLT stub was emitted).func0is present in the AOT image.Note
This pull request was prepared with the assistance of GitHub Copilot.
Part of the MonoAOT LLVM 23 full-AOT regression set tracked by #129508. Built and tested together with the Emscripten 5.0.6 / LLVM 23 bump on #129396, where the re-enabled
call05_large/call05_smalltests pass on theruntime-llvmAllSubsets_Mono_LLVMFULLAOT_RuntimeTestsleg.Contributes to #129508.