llvm-svn: 197039

Before this patch, we had the following class hierarchy.

  Chunk -> AtomChunk -> SectionChunk -> GenericSectionChunk
                                     -> BaseRelocChunk
        -> HeaderChunk

Chunk represented the generic concept of contiguous range in an output
file. AtomChunk represented a chunk consists of atoms.

That class hierarchy had many issues: 1) BaseRelocChunk does not really
consist of atoms, so inheriting from AtomChunk was plainly wrong, and 2)
the hierarchy is unecessarily too deep.

This patch correct them. The new hierachy is shown below.

  Chunk -> SectionChunk -> AtomChunk
                        -> BaseRelocChunk
        -> HeaderChunk

In the new hierarchy, AtomChunk represents a chunk consists of atoms. Other
types of sections (currently only BaseRelocChunk) should inherit directly
from SectionChunk.

llvm-svn: 197038

Also removed unused field.

llvm-svn: 197027

No functionality change.

llvm-svn: 197025

Because sections no longer have trailing NULL bytes, size() and rawSize() now
return the same value.

llvm-svn: 197020

llvm-svn: 197019

llvm-svn: 197018

This patch is to basically move the functionality to construct Data Directory
from IdataPass to WriterPECOFF.

Data Directory is a part of the PE/COFF header and contains the addresses of
the import tables.

We used to represent the link from Data Directory to the import tables as
relocation references. The idea behind it is that, because relocation
references are processed by the Writer, we wouldn't have to do anything special
to fill the addresses of the import tables. I thought that the addresses would
be set "automatically".

But it turned out that that design made the pass and the writer rather
complicated. In order to make relocation references between Data Directory to
the import tables, these data structures needed to be represented as Atom.
However, because Data Directory is not a section content but a part of the
PE/COFF header, it did not fit well as an Atom. So we ended up having
complicated code both in IdataPass and the writer.

This patch simplifies it.

One side effect of this patch is that we now have ".idata.a", ".idata.d" and
"idata.t" sections for the import address table, the import directory table,
and the import lookup table. The writer looks for the sections by name to find
the start addresses of the sections. We probably should have a better way to
find a specific atom from the core linking result, but currently using the
section name seems to be the easiest way to do that. The Windows loader do not
care about the import table's section layout.

llvm-svn: 197016

llvm-svn: 197009

llvm-svn: 197008

llvm-svn: 197007

llvm-svn: 197006

If section size is not multiple of 512, the writer added NULL bytes at the end
of it to make it so. That is not required by the PE/COFF spec, and the MSVC's
linker does not do that too. So we don't need to do that, too.

llvm-svn: 197002

llvm-svn: 196994

The base class has a member function with the same name. We should avoid it
being shadowed.

llvm-svn: 196992

llvm-svn: 196991

llvm-svn: 196898

llvm-svn: 196897

llvm-svn: 196896

Code to create COFF section header was scattered across many member functions
of SectionChunk. Consolidate it to a member function of SectionHeaderTableChunk.

llvm-svn: 196895

llvm-svn: 196891

... because they are used only in the function for relocations.

llvm-svn: 196890

llvm-svn: 196884

llvm-svn: 196883

Use of static is recommended by the style guide.

llvm-svn: 196877

llvm-svn: 196867

These member functions are not overriden and not intended to be, so adding
virtual does not make sense.

llvm-svn: 196866

This reverts commit r196475 because it made the build to fail with
GCC 4.7/4.8/4.9. Reported by Mikael Lyngvig.

llvm-svn: 196853

llvm-svn: 196767

llvm-svn: 196762

llvm-svn: 196754

/ALTERNATENAME is a rarely-used, undocumented command line option that is
needed to link LLD for release build. It seems that the option is for defining
an weak alias; /alternatename:foo=bar defines weak symbol "foo" for "bar".
If "foo" is defined in an input file, it'll be linked normally and the command
line option will have no effect. If it's not defined, "foo" will be handled
as an alias for "bar".

This patch implements the parser for the option. The actual weak alias handling
will be implemented in a separate patch.

llvm-svn: 196743

llvm-svn: 196741

llvm-svn: 196716

Because compare() and its heper functions no longer have to be members of
LayoutPass class, we can remove it from the class. No functionality change.

llvm-svn: 196715

The comparator used in the layout pass has many calls of map::find(). Because
std::sort runs the comparator N*log2(N) times, the maps are looked up with the
same key again and again. The map lookup is not a very fast operation. It made
the pass slow.

This patch eliminates the duplicate map lookups using decorate-sort-undecorate
idiom. The pass used to take 1.1 seconds when linking LLD with LLD on Windows,
but it now takes only 0.3 seconds. Overall performance gain in that case is from
6.1 seconds to 5.2 seconds.

Differential Revision: http://llvm-reviews.chandlerc.com/D2358

llvm-svn: 196714

GroupedSectionsPass was a complicated pass. That pass's job was to reorder
atoms by section name, so that the atoms with the same section prefix will be
emitted consecutively to the executable. The pass added layout edges to atoms,
and let the layout pass to actually reorder them.

This patch simplifies the design by making GroupedSectionPass to directly
reorder atoms, rather than adding layout edges. This resembles ELF's
ArrayOrderPass.

This patch improves the performance of LLD; it used to take 7.1 seconds to
link LLD with LLD on my Macbook Pro, but it now takes 6.1 seconds.

llvm-svn: 196628

llvm-svn: 196564

llvm-svn: 196563

Currently we do not de-duplicate library files specified by /defaultlib option.
As a result, the same files are added multiple times to the input graph. In
particular, some popular files, such as kernel32.lib or oldnames.lib, are added
more than 10 times during linking of LLD. That makes the linker slower, as it
needs to parse the same file again and again.

This patch solves the issue by de-duplicating. The same file will be added only
once to the input graph. This patch improved the LLD linking time from 10.5
seconds to 7.7 seconds on my 4-core Core i7 Macbook Pro.

llvm-svn: 196504