Currently we use both layout-after and layout-before edges to specify atom
orders in the resulting executable. We have a complex piece of code in
LayoutPass.cpp to deal with both types of layout specifiers.
(In the following description, I denote "Atom A having a layout-after edge
to B" as "A -> B", and A's layout-before to B as "A => B".)
However, that complexity is not really needed for this reason: If there
are atoms such that A => B, B -> A is always satisifed, so using only layout-
after relationships will yield the same result as the current code.
Actually we have a piece of complex code that verifies that, for each A -> B,
B => [ X => Y => ... => Z => ] A is satsified, where X, Y, ... Z are all
zero-size atoms. We can get rid of the code from our codebase because layout-
before is basically redundant.
I think we can simplify the code for layout-after even more than this, but
I want to just remove this pass for now for simplicity.
Layout-before edges are still there for dead-stripping, so this change won't
break it. We will remove layout-before in a followup patch once we fix the
dead-stripping pass.
Differential Revision: http://llvm-reviews.chandlerc.com/D3164
llvm-svn: 204966
Use <mutex> instead of "llvm/Support/Mutex.h".
Also change the type of mutex for the context object to recursive mutex, as
the driver could acquire the lock recursively. E.g. If file A has .drectve
section containing /defaultlib:B, the driver tries to parse file B, and if
file B has .drectve section, the driver acquires the lock again.
llvm-svn: 204850
RoundTripYAML pass is removed from the regular execution pass in r204296,
so the safeguard to protect it from OOM error is no longer needed, because
we are sure that the pass is only used for tests, and test files are all
small.
We also want to see RoundTripYAML pass to fail in tests if it fails,
rather than silently skipping failing tests.
llvm-svn: 204772
If a response file is given via command line, the final command line
arguments will not appear in the log because the actual arguments are
in the given file.
This patch is to show the final command line if /verbose is specified
to help users.
llvm-svn: 204754
Response file is not NUL terminated, so when creating a StringRef for
the buffer contents, we need to pass the buffer size as well as the
pointer pointing to the buffer.
llvm-svn: 204420
If the environment variable is defined and not empty, RoundTrip tests
are run. The reason to move the tests behind the flag is because they
are too slow to enable by default.
LLD linking time on llvm-tblgen improved from 2m7s to 2.3s. About 60x
faster now in this case.
Differential Revision: http://llvm-reviews.chandlerc.com/D3126
llvm-svn: 204296
InputElement::parse() may recursively call WinLinkDriver::parse() to handle
.drectve section contents, and if /defaultlib option exists in the section,
the driver will mutate the input graph to add a new input file to the graph.
So the access to input graph needs to be protected with mutext.
llvm-svn: 204285
of GOT.
* Read addend for R_MIPS_GOT16 relocation.
* Put only high 16 bits of symbol + addend into GOT entries for
locally visible symbols.
llvm-svn: 204247
Update all of the unit tests to use the new format.
This depends on D3092.
Reviewers: ruiu
Differential Revision: http://llvm-reviews.chandlerc.com/D3093
llvm-svn: 204215
COMDAT_SELECT_LARGEST is a COMDAT type that make linker to choose the largest
definition from among all of the definition of a symbol. If the size is the
same, the choice is arbitrary.
Differential Revision: http://llvm-reviews.chandlerc.com/D3011
llvm-svn: 204172
The COFF spec says that the SectionNumber field in the symbol table is 16 bit
signed type, but MSVC treats the field as if it is unsigned.
llvm-svn: 203901
LLD fails to link symbol "_main" if the symbol is in a library file and
the library file is given as a bare argument (i.e. not with /defaultlib
option). It's because library files given as bare arguments are processed
before other libraries given with /defaultlib, so when Linker finds msvcrtd
needs a definition for "_main", the file providing the main function has
already been processed and skipped. Linker don't revisit libraries if it's
not given with /defaultlib.
To fix it this patch change the way of command line handling; files end with
".lib" are treated as if they are given with /defaultlib. I don't believe
it's 100% correct behavior but it's better than before.
llvm-svn: 203892
If the driver finds a command line option in the form of "@filename", the
option will be replaced with the content of the given file. It's an error
if a response file cannot be read.
llvm-svn: 203875
This results in some simplifications to the code where an OwningPtr had to
be used with the previous api and then ownership moved to a unique_ptr for
the rest of lld.
llvm-svn: 203809
An object whose machine type header value is unknown looks a bit odd but
is valid. If an object contains only machine-type-independent data, you
can leave the type field unspecified. Some files in oldname.lib are such
object files.
llvm-svn: 203752
Clang creates "clang-cl" as a symlink to (or a copy of) "clang" for the MSVC-
compatible driver. This patch is to do the same thing for "link" and "lld".
Differential Revision: http://llvm-reviews.chandlerc.com/D3066
llvm-svn: 203751
MergeCases table should not have an entry for MergeContents because atoms with
MergeContents attribute should never have name. This issue was not caught by a
test because getting a value of 6th element of an array of array actually gets
the first element's value of the next array, and that happened to be a valid
value. Added asserts to catch that error.
llvm-svn: 203322
Summary:
COMDAT_SELECT_SAME_SIZE is a COMDAT type that I presume exist only in COFF.
The semantics of the type is that linker should merge such COMDAT sections if
their sizes are the same. Otherwise it's an error.
Reviewers: Bigcheese, shankarke, kledzik
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D2996
llvm-svn: 203308
Just like x86 exception handler table, the table for x64 needs to be sorted
so that runtime can binary search on it. Unlike x86, the table entry for x64
has multiple fields, and they need to be sorted according to its BeginAddress
field. This patch also fixes a bug in relocations.
llvm-svn: 202874
C++11. I'm not sure that this is a good idea, but I know some crazy
folks on the core working group who like to live dangerously, and they
should still be able to build LLD. =D
llvm-svn: 202568
It looks like the contents of the table need to be sorted according to its
value, so that the runtime can find the entry by binary search. I'm not 100%
sure if we really have to do that, but at least I can say it's safe to do
because the contents of .sxdata is just a list of exception handlers' RVAs.
llvm-svn: 202550
If all input files are compatible with Structured Exception Handling, linker
is supposed to create an exectuable with a table for SEH handlers. The table
consists of exception handlers entry point addresses.
The basic idea of SEH in x86 Microsoft ABI is to list all valid entry points
of exception handlers in an read-only memory, so that an attacker cannot
override the addresses in it. In x86 ABI, data for exception handling is mostly
on stack, so it's volnerable to stack overflow attack. In order to protect
against it, Windows runtime uses the table to check a return address, to
ensure that the address is really an valid entry point for an exception handler.
Compiler emits a list of exception handler functions to .sxdata section. It
also emits a marker symbol "@feat.00" to indicate that the object is compatible
with SEH. SEH is a relatively new feature for COFF, and mixing SEH-compatible
and SEH-incompatible objects will result in an invalid executable, so is the
marker.
If all input files are compatible with SEH, LLD emits a SEH table. SEH table
needs to be pointed by Load Configuration strucutre, so when emitting a SEH
table LLD emits it too. The address of a Load Configuration will be stored to
the file header.
llvm-svn: 202248
target_link_libraries(INTERFACE) doesn't bring inter-target dependencies in add_library,
although final targets have dependencies to whole dependent libraries.
It makes most libraries can be built in parallel.
target_link_libraries(PRIVATE) is used to shaared library.
Each dependent library is linked to the target.so, and its user will not see its grandchildren.
For example,
- libclang.so has sufficient libclang*.a(s).
- c-index-test requires just only libclang.so.
FIXME: lld is tweaked minimally. Adding INTERFACE in each library would be better thing.
llvm-svn: 202241
For now, use both keywords, INTERFACE and PRIVATE via the variable,
- ${cmake_2_8_12_INTERFACE}
- ${cmake_2_8_12_PRIVATE}
They could be cleaned up when we introduce 2.8.12.
llvm-svn: 202239
This restores the debug output to how it was before r197727 broke it. This
went undetected because the corresponding test was never run due to broken
feature detection.
llvm-svn: 202079
Syntactically /SAFESEH is a boolean flag -- you can pass /SAFESEH or /SAFESEH:no.
The meaning of /SAFESEH is as follows.
- If /SAFESEH is specified, the linker will produce an executable with SEH table.
If any input files are not compatible with SEH, it's an error.
- If /SAFESEH:no is specified, the linker will not emit SEH table even if all
input files are compatible with SEH.
- If no option is specified, the linker emits SEH table if all input files are
compatible with SEH.
llvm-svn: 201895
The sections .rela/.rel.(*) have a alignment of 2 in the final image created by
the linker. This needs to be properly set to the right alignment depending on
the architecture(32/64bits).
llvm-svn: 201740
The target machine type affects the meaning of other options, in particular
how to mangle symbols. So we want to handle the option first and then parse
all the other options.
llvm-svn: 200589
Because the object files are now readable to humans, I don't think we need the
source assembly file any more, so I removed them too in this commit.
llvm-svn: 200276
The comments in the files that described the file name as part of each file
header ran over 80 columns, which clang-format split over multiple lines.
This commit fixes to make them appear properly.
llvm-svn: 200181
ELFFile would be a class that rest of the targets would derive from.
To keep the implementation clean, separate the implementation from
rest of the Header file.
llvm-svn: 200168
Add new virtual virtual function `isRelaOutputFormat` to the
`ELFLinkingContext` class. Call this function everywhere we need to
select a relocation table format.
Patch reviewed by Shankar Easwaran and Rui Ueyama.
llvm-svn: 199973
method returns the DefaultLayout::_segments field. The type of this field is
a vector of Segment<ELFT>* pointers. This type cannot be implicitly casted to
the range<ChunkIter>.
llvm-svn: 199233
Refactor the parser so that the parser can return arbitrary type of parse
result other than a vector of ExportDesc. Parsers for non-EXPORTS directives
will be implemented in different patches. No functionality change.
llvm-svn: 198993
The main goal of this patch is to allow "mach-o encoded as yaml" and "native
encoded as yaml" documents to be intermixed. They are distinguished via
yaml tags at the start of the document. This will enable all mach-o test cases
to be written using yaml instead of checking in object files.
The Registry was extend to allow yaml tag handlers to be registered. The
mach-o Reader adds a yaml tag handler for the tag "!mach-o".
Additionally, this patch fixes some buffer ownership issues. When parsing
mach-o binaries, the mach-o atoms can have pointers back into the memory
mapped .o file. But with yaml encoded mach-o, name and content are ephemeral,
so a copyRefs parameter was added to cause the mach-o atoms to make their
own copy.
llvm-svn: 198986
Module-definition (.def) files are the file containing linker directives,
such as export symbols. Because link.exe supports the same features as command
line options, just as some Linker Script commands overlaps with command line
options, use of module-definition file is not really necessary. It provides
an alternative way to specify some linker options.
This patch implements EXPORTS directive. Other directives will be implemented
in the future.
llvm-svn: 198925
Rui Ueyama