[lld] r244904 - Store the offset in the output section, no in the file.

[Rafael Espíndola via llvm-commits]

r245018.

On 13 August 2015 at 22:26, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
> Sure, I will do that in a sec.
>
> On 13 August 2015 at 22:18, Rui Ueyama <ruiu at google.com> wrote:
>> Can you make the same change for COFF so that the two are not going to
>> unnecessarily diverge?
>>
>> On Fri, Aug 14, 2015 at 12:54 AM, Rafael Espindola via llvm-commits
>> <llvm-commits at lists.llvm.org> wrote:
>>>
>>> Author: rafael
>>> Date: Thu Aug 13 10:54:36 2015
>>> New Revision: 244904
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=244904&view=rev
>>> Log:
>>> Store the offset in the output section, no in the file.
>>>
>>> That is the value that is stable as the we layout the output sections.
>>>
>>> Modified:
>>>     lld/trunk/ELF/Chunks.cpp
>>>     lld/trunk/ELF/Chunks.h
>>>     lld/trunk/ELF/Writer.cpp
>>>
>>> Modified: lld/trunk/ELF/Chunks.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Chunks.cpp?rev=244904&r1=244903&r2=244904&view=diff
>>>
>>> ==============================================================================
>>> --- lld/trunk/ELF/Chunks.cpp (original)
>>> +++ lld/trunk/ELF/Chunks.cpp Thu Aug 13 10:54:36 2015
>>> @@ -33,7 +33,7 @@ template <class ELFT> void SectionChunk<
>>>      return;
>>>    // Copy section contents from source object file to output file.
>>>    ArrayRef<uint8_t> Data = *Obj->getSectionContents(Header);
>>> -  memcpy(Buf + FileOff, Data.data(), Data.size());
>>> +  memcpy(Buf + OutputSectionOff, Data.data(), Data.size());
>>>
>>>    // FIXME: Relocations
>>>  }
>>>
>>> Modified: lld/trunk/ELF/Chunks.h
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Chunks.h?rev=244904&r1=244903&r2=244904&view=diff
>>>
>>> ==============================================================================
>>> --- lld/trunk/ELF/Chunks.h (original)
>>> +++ lld/trunk/ELF/Chunks.h Thu Aug 13 10:54:36 2015
>>> @@ -37,17 +37,18 @@ public:
>>>    virtual void writeTo(uint8_t *Buf) = 0;
>>>
>>>    // The writer sets and uses the addresses.
>>> -  uint64_t getFileOff() { return FileOff; }
>>> +  uint64_t getOutputSectionOff() { return OutputSectionOff; }
>>>    uint32_t getAlign() { return Align; }
>>> -  void setFileOff(uint64_t V) { FileOff = V; }
>>> +  void setOutputSectionOff(uint64_t V) { OutputSectionOff = V; }
>>>
>>>    // Returns the section name if this is a section chunk.
>>>    // It is illegal to call this function on non-section chunks.
>>>    virtual StringRef getSectionName() const = 0;
>>>
>>>  protected:
>>> -  // The offset from beginning of the output file. The writer sets a
>>> value.
>>> -  uint64_t FileOff = 0;
>>> +  // The offset from beginning of the output sections this chunk was
>>> assigned
>>> +  // to. The writer sets a value.
>>> +  uint64_t OutputSectionOff = 0;
>>>
>>>    // The alignment of this chunk. The writer uses the value.
>>>    uint32_t Align = 1;
>>>
>>> Modified: lld/trunk/ELF/Writer.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=244904&r1=244903&r2=244904&view=diff
>>>
>>> ==============================================================================
>>> --- lld/trunk/ELF/Writer.cpp (original)
>>> +++ lld/trunk/ELF/Writer.cpp Thu Aug 13 10:54:36 2015
>>> @@ -50,8 +50,8 @@ public:
>>>
>>>    // Returns the size of the section in the output file.
>>>    uintX_t getSize() { return Header.sh_size; }
>>> -
>>>    uintX_t getFlags() { return Header.sh_flags; }
>>> +  uintX_t getOffset() { return Header.sh_offset; }
>>>
>>>  private:
>>>    StringRef Name;
>>> @@ -122,8 +122,6 @@ template <class ELFT> void OutputSection
>>>    if (Header.sh_size == 0)
>>>      return;
>>>    Header.sh_offset = Off;
>>> -  for (Chunk *C : Chunks)
>>> -    C->setFileOff(C->getFileOff() + Off);
>>>  }
>>>
>>>  template <class ELFT>
>>> @@ -131,7 +129,7 @@ void OutputSection<ELFT>::addSectionChun
>>>    Chunks.push_back(C);
>>>    uintX_t Off = Header.sh_size;
>>>    Off = RoundUpToAlignment(Off, C->getAlign());
>>> -  C->setFileOff(Off);
>>> +  C->setOutputSectionOff(Off);
>>>    Off += C->getSize();
>>>    Header.sh_size = Off;
>>>    Header.sh_type = C->getSectionHdr()->sh_type;
>>> @@ -275,8 +273,9 @@ template <class ELFT> void Writer<ELFT>:
>>>  template <class ELFT> void Writer<ELFT>::writeSections() {
>>>    uint8_t *Buf = Buffer->getBufferStart();
>>>    for (OutputSection<ELFT> *Sec : OutputSections) {
>>> +    uint8_t *SecBuf = Buf + Sec->getOffset();
>>>      for (Chunk *C : Sec->getChunks())
>>> -      C->writeTo(Buf);
>>> +      C->writeTo(SecBuf);
>>>    }
>>>
>>>    // String table.
>>>
>>>
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>>
>>