[Lldb-commits] [lldb] [LLDB] Warn about truncated DWARF section names on Windows (PR #145175)

[via lldb-commits]

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@@ -1036,12 +1036,18 @@ void ObjectFilePECOFF::CreateSections(SectionList &unified_section_list) {
     m_sections_up->AddSection(header_sp);
     unified_section_list.AddSection(header_sp);
 
+    std::vector<llvm::StringRef> truncated_dwarf_sections;
     const uint32_t nsects = m_sect_headers.size();
     for (uint32_t idx = 0; idx < nsects; ++idx) {
       llvm::StringRef sect_name = GetSectionName(m_sect_headers[idx]);
       ConstString const_sect_name(sect_name);
       SectionType section_type = GetSectionType(sect_name, m_sect_headers[idx]);
 
+      // Detect unknown sections matching ^\.debug_[a-z]$
+      if (section_type == eSectionTypeOther && sect_name.size() == 8 &&
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Nerixyz wrote:

> Probably unlikely, but could the truncation change in the future to a different size?

The truncation will always be 8 bytes, because that's how much space the section name has in the PE/COFF section header - it's basically a `char name[8]` field. For longer names, the linker has to write the section name into the string table and set the name in the section header to `/n` where `n` is the offset in the string table.

> Could we just check the section_type and prefix and issue a warning saying "unrecognized section, possibly got truncated"?

That could be an additional diagnostic for unknown DWARF sections (should probably be there for other object files as well). If the section name is 8 bytes, however, we can be sure this is from someone using link.exe.

As an extension, this could be present for `.lldbformatters` and `.lldbsummaries` as well. In this specific case, the matching could also consider `.lldbfor` and `.lldbsum`, because there are only two.

> Do we need the `size == 8` and `isLower` checks here?

We need the size check, but I removed the isLower check, because the indicator for DWARF is `.debug_`.

https://github.com/llvm/llvm-project/pull/145175