Bad line number in this example

[mstange]

This might just be a case of bad debug information in the pdb, but I'd like to file it anyways.

In this profile, the ExtractLoadingEventsToProcess frame blames line 565. But the inline stack shows that we're in an erase call, and that call is at line 567.

$ pdb-addr2line -pCfi -e ~/sym/xul.pdb/CC23F2389DBF02D74C4C44205044422E1/xul.pdb 0x126f980
nsTSubstring<char>::Assign(nsTSubstring<char>&&) at /builds/worker/checkouts/gecko/xpcom/string/nsTSubstring.cpp:495
 (inlined by) nsTString<char>::operator=(nsTString<char>&&) at /builds/worker/workspace/obj-build/dist/include/nsTString.h:123
 (inlined by) mozilla::glue::EnhancedModuleLoadInfo::operator=(mozilla::glue::EnhancedModuleLoadInfo&&) at /builds/worker/workspace/obj-build/dist/include/mozilla/glue/WindowsDllServices.h:133
 (inlined by) mozilla::Vector<mozilla::glue::EnhancedModuleLoadInfo,0,mozilla::MallocAllocPolicy>::erase(mozilla::glue::EnhancedModuleLoadInfo*, mozilla::glue::EnhancedModuleLoadInfo*) at /builds/worker/workspace/obj-build/dist/include/mozilla/Vector.h:1334
 (inlined by) mozilla::UntrustedModulesProcessor::ExtractLoadingEventsToProcess(unsigned long long) at /builds/worker/checkouts/gecko/toolkit/xre/dllservices/UntrustedModulesProcessor.cpp:565

Link to this xul.pdb.cab

[mstange]

The first InlineRange for the inlined erase call looks like this:

    InlineRange {
        start_offset: 19327166,
        end_offset: 19327369,
        call_depth: 0,
        inlinee: IdIndex(0xda407),
        file_index: Some(
            FileIndex(0x108),
        ),
        line_start: Some(
            1334,
        ),
    },

So it starts at section offset 19327166. The line numbers for the outer function come from the line program, which uses apdb LineIterator. The last record from that iterator is translated into the following CachedLineInfo:

    CachedLineInfo {
        start_offset: 19326851,
        file_index: FileIndex(0x558),
        line_start: 565,
    },

section offsets:
19326851 last line record
19327166 first "erase" inlinee

It looks like we're missing an entry in the line program here. Or maybe there is some reason why the line iterator stops early.