The import name is not always the same as the symbol name. If the name/type
field in the import header is NOPREFIX or UNDECORATE, we need to strip some
characters from symbol to get its import name.

The Microsoft PE/COFF spec is vague if symbol contains more than two
consecutive characters to be stripped. We used to strip all characters,
but it doesn't seem right as we couldn't link against the system library
because of this name mangling. Looks like we shouldn't strip more than one
character.

llvm-svn: 188154

__ImageBase is a symbol having 4 byte integer equal to the image base address
of the resultant executable. The linker is expected to create the symbol as if
it were read from a file.

In order to emit the symbol contents only when the symbol is actually
referenced, we created a pseudo library file to wrap the linker generated
symbol. The library file member is emitted to the output only when the member
is actually referenced, which is suitable for our purpose.

llvm-svn: 188052

The COMDAT section is a section with a special attribute to tell the linker
whether the symbols in the section are allowed to be merged or not. This patch
add a function to interpret the COMDAT data and set "merge" attribute to the
atoms accordingly.

LLD supports multiple policies to merge atoms; atoms can be merged by name or
by content. COFF supports them, and in addition to that, it supports
choose-the-largest-atom policy, which LLD currently does not support. I simply
mapped it to merge-by-name attribute for now, but we eventually have to support
that policy in the core linker.

llvm-svn: 188025

llvm-svn: 188011

Summary:
The .drectve section contains linker command line options, and the linker is
expected to interpret them as if they were given via the command line. In this
patch, the command line parser in the driver is called from the object file
reader to parse the string.

I think this patch is important, because this is the first step towards mutable
TargetInfo. We had a discussion about that on llvm-commits mailing list before.
I haven't removed "const" from the function signature yet. Instead, I just use
cast to remove "const". This is a temporary aid for an experiment. If we don't
see any issue with this mutable TargetInfo appraoch, I'll change the function
signature, and rename the class LinkerContext from TargetInfo.

Reviewers: kledzik

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1246

llvm-svn: 187677

Patch by Ron Ofir.

llvm-svn: 187664

llvm-svn: 187645

llvm-svn: 187460

This patch removes hacky mangle() function, which strips all decorations
uncondtitionally. LLD now interprets Import Name/Type field in the import
library properly as described in the Microsoft PE/COFF Spec.

llvm-svn: 187388

Some sections, such as with IMAGE_SCN_LNK_REMOVE attribute, is skipped
in the first pass. Such sections need to be skipped in the latter passes.

llvm-svn: 187281

Based on Ron Ofir's patch.

llvm-svn: 187221

llvm-svn: 187170

llvm-svn: 187100

LLD still accepts both Unix and Windows style options when it's run as
link.exe. This patch does not change functionality.

llvm-svn: 187086

The /include command line option is equivalent to Unix --undefined
option, which forces the linker to resolve the given symbol name
as if it's an unresolved symbol in one of its input files. This feature
is used to link an additional object file or a shared library that no
input files refer to.

llvm-svn: 187084

llvm-svn: 186911

llvm-svn: 186739

llvm-svn: 186654

llvm-svn: 186650

llvm-svn: 186648

llvm-svn: 186645

Emit .reloc section. This is the first step to support DLL creation. The
executable doesn't need .reloc section, but the DLL does.

Reviewers: Bigcheese

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1126

llvm-svn: 186336

This patch adds a new pass, IdataPass, to transform shared atom references
to real references and to construct the .idata section data. With this patch
lld can produce a working Hello World program by linking it against
kernel32.dll and user32.dll.

Reviewers: Bigcheese

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1096

llvm-svn: 186071

llvm-svn: 186066

llvm-svn: 185690

llvm-svn: 185534

llvm-svn: 185310

llvm-svn: 185308

llvm-svn: 185283

llvm-svn: 185205

llvm-svn: 185133

llvm-svn: 185130

llvm-svn: 185129

llvm-svn: 185102

Reviewers: shankarke

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D998

llvm-svn: 184327

This is the first patch toward full DLL support. With this patch, lld can
read .lib file for a DLL.

Reviewers: Bigcheese

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D987

llvm-svn: 184101

With this patch, it can now resolve relocations in the same output file.
"Hello world" program does not still work because call to the DLL routine
is not supported yet.

Reviewers: Bigcheese

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D985

llvm-svn: 184063

llvm-svn: 184037

Archive file in Windows has file extension of ".lib" but the file format is
in fact the same as Unix. It's an ar archive holding multiple .obj files.
The existing archive reader can read .lib files.

llvm-svn: 184036

llvm-svn: 184035