Mangling scheme varies on platform, and prepending an underscore is valid only
on 32-bit x86. Added a method to mangle name to PECOFFLinkingContext and use
it to avoid hard coding mangled names.
llvm-svn: 190585
The compiler is allowed to add a linker option starting with -?<name> to
.drectve section. If the linker can interpret -<name>, it's processed as if
there's no question mark there. If not, such option is silently ignored.
This is a COFF's feature to allow the compiler to emit new linker options
while keeping compatibility with older linkers.
llvm-svn: 189897
This adds an API to the LinkingContext for flavors to add Internal files
containing atoms that need to appear in the YAML output as well, when -emit-yaml
switch is used.
Flavors can add more internal files for other options that are needed.
llvm-svn: 189718
We added layout edges to the head atoms in grouped sections. That was wrong,
because the head atom needs to be followed by the other atoms in the *same*
section, not by the other section contents. With this patch, layout edges are
added from tail atom, which is the last atom in a section, to head atom.
llvm-svn: 189573
Because of a bug, the last atom of each section contained a garbage at the
end of its data. In most cases the garbage is harmless but it could have cause
SEGV.
llvm-svn: 189572
We were creating undefined atoms for common symbols by mistake. That did not
lead to a link failure, for undefined atoms would be resolved by common symbols
in the same file, but that's a waste of resource.
llvm-svn: 189534
We scanned the symbol table twice; first to gather all regular symbols, and
second to process aux symbols. That's a bit inefficient and complicated. We
can instead cache aux symbols in the first pass, to eliminate the need of the
second pass.
llvm-svn: 189525
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
Also change some local variable names: "ti" -> "context" and
"_targetInfo" -> "_context".
Differential Revision: http://llvm-reviews.chandlerc.com/D1301
llvm-svn: 187823
The aim of this patch is to reduce the dependency from COFFDefinedAtom
to COFF structs defined in llvm/Object/COFF.h. Currently many attributes
of the atom are computed in the atom. That provide a simple interface but
does not work well in some cases.
There are some cases that the same type atom is created from different
parts of a COFF file. One example is the BSS atom, which can be created
from the defined symbol in the .bss section or from the undefined symbol.
Computing attributes from different sources in the atom complicates the
code. We should compute it outside the atom.
In the next patch, I'll move more code from Atoms.h to ReaderCOFF.cpp.
llvm-svn: 187681
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
For an invalid input we should not call report_fatal_error(), because
when LLD is used as a library, we don't want to kill the whole app
because of a malformed input.
llvm-svn: 187673
A instance of the class always represents a BSS atom, so we don't need
to look at the symbol or the section to retrieve its attributes.
llvm-svn: 187643
The BSS atom is similar to the regular defined atom, but it's different
in the sense that it does not have contents. Until now we assumed all the
defined atoms have its contents. That did not fit well to the BSS atom.
llvm-svn: 187453
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
Rui Ueyama