Native AOT DWARF info contains many overlapping ranges #83233

agocke · 2023-03-09T21:26:13Z

dwarfdump --verify shows examples of this:

error: DIE address ranges are not contained in its parent's ranges:
0x0000000b: DW_TAG_compile_unit [1] *
DW_AT_producer [DW_FORM_string] ("CoreRT")
DW_AT_language [DW_FORM_data2] (DW_LANG_C_plus_plus)
DW_AT_name [DW_FORM_string] ("IL.c")
DW_AT_comp_dir [DW_FORM_string] ("/tmp")
DW_AT_low_pc [DW_FORM_addr] (0x0000000000000000)
DW_AT_high_pc [DW_FORM_data8] (0x0000000000000000)
DW_AT_stmt_list [DW_FORM_sec_offset] (0x00000000)

0x0006cece: DW_TAG_subprogram [11] * (0x0000000b)
DW_AT_specification [DW_FORM_ref4] (cu + 0x518ab => {0x000518ab} "System_IO_Pipes_Interop__GetExceptionForIoErrno")
DW_AT_low_pc [DW_FORM_addr] (0x0000000000072500)
DW_AT_high_pc [DW_FORM_data8] (0x0000000000000569)
DW_AT_frame_base [DW_FORM_exprloc] (DW_OP_reg6) ranges: (occurs 1683 times)

This seems like it's related to inlining. If so, I would expect DW_TAG_inlined_subroutine entries, but I'm not seeing anything from the JITed code, only from the linked C++.

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dotnet-issue-labeler · 2023-03-09T21:26:16Z

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

ghost · 2023-03-09T21:26:28Z

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch, @kunalspathak
See info in area-owners.md if you want to be subscribed.

Issue Details

dwarfdump --verify shows examples of this:

error: DIE address ranges are not contained in its parent's ranges:
0x0000000b: DW_TAG_compile_unit [1] *
DW_AT_producer [DW_FORM_string] ("CoreRT")
DW_AT_language [DW_FORM_data2] (DW_LANG_C_plus_plus)
DW_AT_name [DW_FORM_string] ("IL.c")
DW_AT_comp_dir [DW_FORM_string] ("/tmp")
DW_AT_low_pc [DW_FORM_addr] (0x0000000000000000)
DW_AT_high_pc [DW_FORM_data8] (0x0000000000000000)
DW_AT_stmt_list [DW_FORM_sec_offset] (0x00000000)

0x0006cece: DW_TAG_subprogram [11] * (0x0000000b)
DW_AT_specification [DW_FORM_ref4] (cu + 0x518ab => {0x000518ab} "System_IO_Pipes_Interop__GetExceptionForIoErrno")
DW_AT_low_pc [DW_FORM_addr] (0x0000000000072500)
DW_AT_high_pc [DW_FORM_data8] (0x0000000000000569)
DW_AT_frame_base [DW_FORM_exprloc] (DW_OP_reg6) ranges: (occurs 1683 times)

This seems like it's related to inlining. If so, I would expect DW_TAG_inlined_subroutine entries, but I'm not seeing anything from the JITed code, only from the linked C++.

Author:	agocke
Assignees:	-
Labels:	`area-CodeGen-coreclr`
Milestone:	-

jakobbotsch · 2023-03-09T22:07:45Z

I'm struggling to read the output here -- what is the error saying? What are the source mappings returned from the JIT that resulted in these DWARF ranges (or is this from variable ranges?)

The JIT does not support reporting debug information in inlinees unless rich debug information is enabled (DOTNET_RichDebugInfo=1). However, even without rich debug information things are normalized back to the root method.

jakobbotsch · 2023-03-09T22:36:43Z

Maybe ILC is emitting an incorrect DW_AT_high_pc (which is 0) for the DW_TAG_compile_unit? Is the error saying that it expected the DW_TAG_subprogram to be contained in the compile unit?

agocke · 2023-03-09T22:54:36Z

Sorry, that was a bad exmaple, maybe this one is better:

error: DIEs have overlapping address ranges:
0x0006cff1: DW_TAG_lexical_block [35] * (0x0006cfae)
              DW_AT_low_pc [DW_FORM_addr]       (0x0000000000072bf5)
              DW_AT_high_pc [DW_FORM_data8]     (0x0000000000000007)

0x0006cfd2: DW_TAG_lexical_block [35] * (0x0006cfae)
              DW_AT_low_pc [DW_FORM_addr]       (0x0000000000072bbc)
              DW_AT_high_pc [DW_FORM_data8]     (0x000000000000003c)

agocke · 2023-03-09T22:54:52Z

The nesting is a different issue.

agocke · 2023-03-09T22:59:57Z

If you use the dwarfdump binary from the native AOT smoke tests, you should be able to get an actual binary.

agocke · 2023-03-09T23:12:25Z

The emit for these things is at https://github.com/dotnet/llvm-project/blob/eb39d072da0ffac93bf087e4d8196b7133ee3a0f/llvm/tools/objwriter/debugInfo/dwarf/dwarfGen.cpp#L564

Lexical scopes are created https://github.com/dotnet/llvm-project/blob/eb39d072da0ffac93bf087e4d8196b7133ee3a0f/llvm/tools/objwriter/debugInfo/dwarf/dwarfGen.cpp#L858

And an example of where variable infos are from https://github.com/dotnet/llvm-project/blob/eb39d072da0ffac93bf087e4d8196b7133ee3a0f/llvm/tools/objwriter/debugInfo/dwarf/dwarfGen.cpp#L697

And that all maps back to https://github.com/dotnet/llvm-project/blob/eb39d072da0ffac93bf087e4d8196b7133ee3a0f/llvm/tools/objwriter/cordebuginfo.h#L329

jakobbotsch · 2023-03-09T23:28:13Z

Gotcha, thank you, I'll try to take a closer look. It sounds feasible that the JIT is emitting an incorrect variable range here.

jakobbotsch · 2023-05-17T10:40:55Z

Looking at the following error:

error: DIEs have overlapping address ranges:
0x0006a2a3: DW_TAG_lexical_block [35] * (0x0006a260)
              DW_AT_low_pc [DW_FORM_addr]	(0x0000000000072e05)
              DW_AT_high_pc [DW_FORM_data8]	(0x0000000000000007)

0x0006a284: DW_TAG_lexical_block [35] * (0x0006a260)
              DW_AT_low_pc [DW_FORM_addr]	(0x0000000000072dcc)
              DW_AT_high_pc [DW_FORM_data8]	(0x000000000000003c)

Those lexical scopes are clearly not nested correctly in the DWARF info.

The function is System.IO.Pipes.Interop+Sys:StrError. The variable ranges returned by the JIT are:

VarLocInfo count is 4
; Variable debug info: 3 live ranges, 3 vars for method Interop+Sys:StrError(int):System.String
(V00 arg0) : From 00000000h to 0000002Ch, in rdi
(V01 loc0) : From 0000002Ch to 00000068h, in rbx
(V02 loc1) : From 00000065h to 0000006Ch, in rdi

which seems quite reasonable. So probably the error is in the translation of these ranges into DWARF format. There is no expectation that live var ranges are guaranteed to be lexically nested, so if DwarfGen is creating lexical scopes for each live var ranges then it makes sense that it causes errors.
Will try to look into why these lexical scopes are created and the correct way to represent these live ranges in DWARF.

jakobbotsch · 2023-05-17T10:52:29Z

So I guess those inner scopes are created here:
https://github.com/dotnet/llvm-project/blob/eb39d072da0ffac93bf087e4d8196b7133ee3a0f/llvm/tools/objwriter/debugInfo/dwarf/dwarfGen.cpp#L531-L547

I would expect we shouldn't be creating these scopes at all and relying on the code that adds the variables to .debug_loc that @agocke linked above:
https://github.com/dotnet/llvm-project/blob/eb39d072da0ffac93bf087e4d8196b7133ee3a0f/llvm/tools/objwriter/debugInfo/dwarf/dwarfGen.cpp#L697

ghost · 2023-06-09T16:16:04Z

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

dwarfdump --verify shows examples of this:

error: DIE address ranges are not contained in its parent's ranges:
0x0000000b: DW_TAG_compile_unit [1] *
DW_AT_producer [DW_FORM_string] ("CoreRT")
DW_AT_language [DW_FORM_data2] (DW_LANG_C_plus_plus)
DW_AT_name [DW_FORM_string] ("IL.c")
DW_AT_comp_dir [DW_FORM_string] ("/tmp")
DW_AT_low_pc [DW_FORM_addr] (0x0000000000000000)
DW_AT_high_pc [DW_FORM_data8] (0x0000000000000000)
DW_AT_stmt_list [DW_FORM_sec_offset] (0x00000000)

0x0006cece: DW_TAG_subprogram [11] * (0x0000000b)
DW_AT_specification [DW_FORM_ref4] (cu + 0x518ab => {0x000518ab} "System_IO_Pipes_Interop__GetExceptionForIoErrno")
DW_AT_low_pc [DW_FORM_addr] (0x0000000000072500)
DW_AT_high_pc [DW_FORM_data8] (0x0000000000000569)
DW_AT_frame_base [DW_FORM_exprloc] (DW_OP_reg6) ranges: (occurs 1683 times)

This seems like it's related to inlining. If so, I would expect DW_TAG_inlined_subroutine entries, but I'm not seeing anything from the JITed code, only from the linked C++.

Author:	agocke
Assignees:	agocke
Labels:	`area-CodeGen-coreclr`, `area-NativeAOT-coreclr`
Milestone:	8.0.0

MichalStrehovsky · 2023-08-01T00:03:50Z

I fixed most of the overlapping range issues in #89488. It fell into a JitInterface trap where on JitInterface we have fields named "Length" that are not actually populated as lengths in RyuJIT (#5282).

I believe the only remaining issue is with overlapping regions that are related to CORINFO_EH_CLAUSE_SAMETRY. Not sure how to represent that with DWARF.

agocke · 2023-08-09T03:36:40Z

Yeah, the vast majority of the issues discussed here have been fixed. I filed a new bug for the last few issues that are left. #90209

ghost added the untriaged New issue has not been triaged by the area owner label Mar 9, 2023

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agocke added this to AppModel Mar 9, 2023

AustinWise mentioned this issue Mar 10, 2023

NativeAOT: dwarfdump --verify produces thousands of warnings and errors #72552

Closed

JulieLeeMSFT assigned jakobbotsch Apr 13, 2023

JulieLeeMSFT added this to the 8.0.0 milestone Apr 13, 2023

JulieLeeMSFT added the untriaged New issue has not been triaged by the area owner label Apr 13, 2023

JulieLeeMSFT removed the untriaged New issue has not been triaged by the area owner label May 11, 2023

agocke assigned agocke and unassigned jakobbotsch May 23, 2023

JulieLeeMSFT added area-NativeAOT-coreclr and removed area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI labels Jun 9, 2023

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Native AOT DWARF info contains many overlapping ranges #83233

Native AOT DWARF info contains many overlapping ranges #83233

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agocke commented Aug 9, 2023

Native AOT DWARF info contains many overlapping ranges #83233

Native AOT DWARF info contains many overlapping ranges #83233

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