[PATCH] D24706: [ELF] - Partial support of --gdb-index command line option (Part 1).

[Rui Ueyama via llvm-commits]

ruiu added inline comments.

================
Comment at: ELF/OutputSections.cpp:65
@@ +64,3 @@
+  if (!DebugInfoSec) {
+    error(".debug_info is required for building .gdb_index");
+    return false;
----------------
Please include a file name in the error message.

================
Comment at: ELF/OutputSections.cpp:71
@@ +70,3 @@
+  for (InputSection<ELFT> *I : IS)
+    DwarfInfoReader<ELFT>(*this, I).addToGdbIndex();
+  return true;
----------------
Looks like this can be written in a more functional programming style like this.

  CompilationUnits = readDwarf(I);

where readDwarf is a new function that returns a new vector.

Currently, it is not clear what DwarfInfoReader would do to its arguments.

================
Comment at: ELF/OutputSections.cpp:86-110
@@ +85,27 @@
+template <class ELFT> void GdbIndexSection<ELFT>::writeTo(uint8_t *Buf) {
+  // Write version.
+  write32le(Buf, 7);
+  Buf += 4;
+
+  write32le(Buf, CuListOffset);
+  Buf += 4;
+
+  // Offset of the types CU list.
+  write32le(Buf, CuTypesOffset);
+  Buf += 4;
+
+  // Offset of the address area, the same as offset of the types CU list,
+  // as we dont support types CU lists, so it is empty.
+  write32le(Buf, CuTypesOffset);
+  Buf += 4;
+
+  // Offset of the symbol table, the same as offset of the types CU list,
+  // we do not fill it yet.
+  write32le(Buf, CuTypesOffset);
+  Buf += 4;
+
+  // Offset of the constant pool, the same as offset of the types CU list,
+  // we do not fill it yet.
+  write32le(Buf, CuTypesOffset);
+  Buf += 4;
+
----------------
I'd save lines here.

  write32le(Buf, 7);                   // Version
  write32le(Buf + 4, CutListOffset);   // [what is this?]
  write32le(Buf + 8, CutListOffset);   // Offset of the address area
  write32le(Buf + 12, CutListOffset);  // ...
  ...
  Buf += 24;

Or, maybe we should define a struct for the header in libObject/libSupport.


https://reviews.llvm.org/D24706