[PATCH] D26210: Define DbiStreamBuilder::addSectionContribs.

[Zachary Turner via llvm-commits]

zturner added inline comments.


================
Comment at: lib/DebugInfo/PDB/Raw/DbiStreamBuilder.cpp:315
+    Entry.Size = Sec.SizeOfRawData;
+    Entry.Characteristics = Sec.Characteristics;
+  }
----------------
ruiu wrote:
> zturner wrote:
> > I think you should try to fill out `Entry.ISect` and `Entry.IMod`.  The first one seems like it's probably just the index, so you could get it by iterating over using `llvm::enumerate()`.  Not sure how you will get the last one, but it seems important nonetheless.  What do you think?
> I will fill `ISect` but probably not `IMod` in this patch because I don't understand the meaning of the field yet.
`IMod` is the index of the module in the DBI Stream's `ModInfo` array.  For example, if this section contribution is for `foo.obj`, and `foo.obj` is the 7th entry in the `ModInfo` array, then `IMod` would be 7.  For example, if I run `-section-contribs` against `empty.pdb` I get this:

```
Section Contributions [
  Contribution {
    ISect: 1
    Off: 0
    Size: 10
    Characteristics [ (0x60000020)
      IMAGE_SCN_CNT_CODE (0x20)
      IMAGE_SCN_MEM_EXECUTE (0x20000000)
      IMAGE_SCN_MEM_READ (0x40000000)
    ]
    Module {
      Index: 1
      Name: * Linker *
    }
    Data CRC: 0
    Reloc CRC: 0
  }
  Contribution {
    ISect: 1
    Off: 16
    Size: 10
    Characteristics [ (0x60500020)
      IMAGE_SCN_ALIGN_16BYTES (0x500000)
      IMAGE_SCN_CNT_CODE (0x20)
      IMAGE_SCN_MEM_EXECUTE (0x20000000)
      IMAGE_SCN_MEM_READ (0x40000000)
    ]
    Module {
      Index: 0
      Name: d:\src\llvm\test\DebugInfo\PDB\Inputs\empty.obj
    }
    Data CRC: 3617027124
    Reloc CRC: 0
  }
```

We have indices of 1 and 0.  Now if I run with `-modules`, I get this:

```
  Modules [
    {
      Name: d:\src\llvm\test\DebugInfo\PDB\Inputs\empty.obj
      Debug Stream Index: 12
      Object File Name: d:\src\llvm\test\DebugInfo\PDB\Inputs\empty.obj
      Num Files: 1
      Source File Name Idx: 0
      Pdb File Name Idx: 0
      Line Info Byte Size: 0
      C13 Line Info Byte Size: 88
      Symbol Byte Size: 208
      Type Server Index: 0
      Has EC Info: No
    }
    {
      Name: * Linker *
      Debug Stream Index: 14
      Object File Name:
      Num Files: 0
      Source File Name Idx: 0
      Pdb File Name Idx: 1
      Line Info Byte Size: 0
      C13 Line Info Byte Size: 0
      Symbol Byte Size: 516
      Type Server Index: 0
      Has EC Info: No
    }
```

and we can see that the `IMod` field matches up with the order of the module in the module info array.


https://reviews.llvm.org/D26210