[lld] [lld][ELF] Add --debug-names to create merged .debug_names. (PR #86508)

[David Blaikie via llvm-commits]

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@@ -2711,6 +2714,599 @@ static uint32_t computeGdbHash(StringRef s) {
   return h;
 }
 
+// 4-byte alignment ensures that values in the hash lookup table and the name
+// table are aligned.
+DebugNamesBaseSection::DebugNamesBaseSection()
+    : SyntheticSection(0, SHT_PROGBITS, 4, ".debug_names") {}
+
+// Get the size of the .debug_names section header in bytes for DWARF32:
+static uint32_t getDebugNamesHeaderSize(uint32_t augmentationStringSize) {
+  return /* unit length */ 4 +
+         /* version */ 2 +
+         /* padding */ 2 +
+         /* CU count */ 4 +
+         /* TU count */ 4 +
+         /* Foreign TU count */ 4 +
+         /* Bucket Count */ 4 +
+         /* Name Count */ 4 +
+         /* Abbrev table size */ 4 +
+         /* Augmentation string size */ 4 +
+         /* Augmentation string */ augmentationStringSize;
+}
+
+void DebugNamesBaseSection::parseDebugNames(
+    InputChunk &inputChunk, OutputChunk &chunk,
+    DWARFDataExtractor &namesExtractor, DataExtractor &strExtractor,
+    function_ref<SmallVector<uint32_t, 0>(
+        uint32_t numCus, const DWARFDebugNames::Header &,
+        const DWARFDebugNames::DWARFDebugNamesOffsets &)>
+        readOffsets) {
+  const LLDDWARFSection namesSec = inputChunk.section;
----------------
dwblaikie wrote:

This patch seems to somewhat arbitrarily use const on top-level (non-reference) type locals. LLVM generally doesn't use top-level const on locals - maybe LLD does moreso? But I'd personally (maybe check with @maskray in case there's some other convention to follow) remove it - it can be confusing (the reader may wonder if the local was meant to be const ref, or if there's something unique about this local that means it should be const when some other local (that isn't modified) is not marked const)

https://github.com/llvm/llvm-project/pull/86508