Fix debugger interaction in the interpreter

[davidwrighton]

Fix various points in the runtime which need to handle the situation of the interpreter precode existing, and allowing the interpreter precode to be considered "part" of the code of the method.

I expect that we may eventually need to treat the interpreter precode as either the "hot" or "cold" code region of the function, but I'm not certain of that yet.

[Copilot]

Pull Request Overview

This PR fixes various points in the CoreCLR runtime to properly handle the interpreter precode when interacting with the debugger. The changes ensure that the interpreter precode is considered "part" of the method code during debugging operations and code analysis.

Key changes:

• Modifies code discovery logic to handle interpreter precodes by following them to their actual bytecode addresses
• Updates method compilation checks to use HasNativeCode() instead of direct null checks
• Removes obsolete interpreter-specific code from event tracing that's now handled more generically

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/coreclr/vm/multicorejitplayer.cpp	Updates method compilation check to use HasNativeCode() method
src/coreclr/vm/method.cpp	Adds interpreter precode handling in NonVirtualEntry2MethodDesc function
src/coreclr/vm/jitinterface.cpp	Adds interpreter precode detection and bytecode address resolution in EECodeInfo::Init
src/coreclr/vm/eventtrace.cpp	Removes obsolete interpreter-specific code handling
src/coreclr/debug/daccess/task.cpp	Refactors code address retrieval in GetRepresentativeEntryAddress
src/coreclr/debug/daccess/dacdbiimpl.cpp	Fixes hot region initialization to include start address

[Copilot]

There is an extra closing parenthesis that will cause a compilation error.

Suggested change

	if (stubPrecode->GetType() == PRECODE_INTERPRETER))
	if (stubPrecode->GetType() == PRECODE_INTERPRETER)

[Copilot]

The variable 'pStubPrecode' is used but not defined. It should be 'stubPrecode' to match the variable declared on line 2226.

Suggested change

	entryPoint = dac_cast<PTR_InterpreterPrecode>(pStubPrecode)->GetData()->ByteCodeAddr;
	entryPoint = dac_cast<PTR_InterpreterPrecode>(stubPrecode)->GetData()->ByteCodeAddr;

[Copilot]

The parentheses around 'stubPrecode' are unnecessary and the cast should be removed. It should be 'return stubPrecode->GetMethodDesc();'

Suggested change

	return (MethodDesc*)(stubPrecode)->GetMethodDesc();
	return stubPrecode->GetMethodDesc();

[kg]

I think it wants (MethodDesc*)(stubPrecode->GetMethodDesc()), which feels better to me also

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[jkotas]

This will end up creating codeinfo for a different IP than the one passed into Init. I can imagine that it is fixing a problem somewhere, but it is likely creating different problems somewhere else. Is this going to break places like

runtime/src/coreclr/vm/threadsuspend.cpp

Lines 5787 to 5789 in 2a95831

	EECodeInfo codeInfo(ip);
	if (!codeInfo.IsValid())
	return;

where we expect the valid EECodeInfo to have real code with GCInfo, etc. behind it?

[jkotas]

Fix various points in the runtime which need to handle the situation of the interpreter precode existing, and allowing the interpreter precode to be considered "part" of the code of the method.

What is the exact path that motivated this fix?

[davidwrighton]

@jkotas, the interpreter precode is built as part of the interpreter codegen process, and placed into the NativeCode slot in the exact same place that the jitted code would go. Thus it gets used as the proxy for the interpreter compiled byte code all over the codebase. The path which is most visible is that this impacts the way the debugger looks at the process. The easiest path to hit where this fixes things is the behavior of !clrstack. Without this fix, the DAC fails to validate that any MethodDesc with generated interpreted code is a valid MethodDesc. This causes the reporting of stack traces to only show the IP within the interpreter bytecode, but not the name of methods. This could easily be fixed by a one off fix, but there are many such instances of issues. Consider delegate target IP to MethodDesc computation. This would be fixed by this change. Etc. I generally think that we'll end up treating the interpreter precode as a sort of adjunct to the interpreter byte code.

[jkotas]

Consider delegate target IP to MethodDesc computation. This would be fixed by this change.

runtime/src/coreclr/vm/method.cpp

Line 2201 in 6f0ce34

MethodDesc* NonVirtualEntry2MethodDesc(PCODE entryPoint)

is main path for delegate IP to MethodDesc mapping. It does not go through EECodeInfo, so I do not think it is affected by this change. If I am reading the code correctly, it should work fine - STUB_CODE_BLOCK_STUBPRECODE path should take care of it. Is that right?

If there is a need to map interpreter precode to MethodDesc, my thinking is that it should go through InterpreterPrecode::GetMethodDesc like the delegate mapping path. EECodeInfo should be only used to deal with actual JITed code IPs without magic.

[davidwrighton]

I've merged a less complete version of this which is enough for !clrstack. Possibly we may want to pull some more of this logic in the future, but for now, this should be enough.