Owning the buffer is somewhat inflexible. Some Binaries have sub Binaries
(like Archive) and we had to create dummy buffers just to handle that. It is
also a bad fit for IRObjectFile where the Module wants to own the buffer too.
Keeping this ownership would make supporting IR inside native objects
particularly painful.
This patch focuses in lib/Object. If something elsewhere used to own an Binary,
now it also owns a MemoryBuffer.
This patch introduces a few new types.
* MemoryBufferRef. This is just a pair of StringRefs for the data and name.
This is to MemoryBuffer as StringRef is to std::string.
* OwningBinary. A combination of Binary and a MemoryBuffer. This is needed
for convenience functions that take a filename and return both the
buffer and the Binary using that buffer.
The C api now uses OwningBinary to avoid any change in semantics. I will start
a new thread to see if we want to change it and how.
llvm-svn: 216002
createBinary documented that it destroyed the parameter in error cases,
though by observation it does not. By passing the unique_ptr by value
rather than lvalue reference, callers are now explicit about passing
ownership and the function implements the documented contract. Remove
the explicit documentation, since now the behavior cannot be anything
other than what was documented, so it's redundant.
Also drops a unique_ptr::release in llvm-nm that was always run on a
null unique_ptr anyway.
llvm-svn: 213557
This makes the buffer ownership on error conditions very natural. The buffer
is only moved out of the argument if an object is constructed that now
owns the buffer.
llvm-svn: 211546
This allows us to just use a std::unique_ptr to store the pointer to the buffer.
The flip side is that they have to support releasing the buffer back to the
caller.
Overall this looks like a more efficient and less brittle api.
llvm-svn: 211542
This will allow external callers of these functions to switch over time
rather than forcing a breaking change all a once. These particular
functions were determined by building clang/lld/lldb.
llvm-svn: 202959
This interface allows IRObjectFile to be implemented without having dummy
methods for all section and segment related methods.
Both llvm-ar and llvm-nm are changed to use it. Unfortunately the mangler is
still not plugged in since it requires some refactoring to make a Module hold
a DataLayout.
llvm-svn: 201881
The constructors of classes deriving from Binary normally take an error_code
as an argument to the constructor. My original intent was to change them
to have a trivial constructor and move the initial parsing logic to a static
method returning an ErrorOr. I changed my mind because:
* A constructor with an error_code out parameter is extremely convenient from
the implementation side. We can incrementally construct the object and give
up when we find an error.
* It is very efficient when constructing on the stack or when there is no
error. The only inefficient case is where heap allocating and an error is
found (we have to free the memory).
The result is that this is a much smaller patch. It just standardizes the
create* helpers to return an ErrorOr.
Almost no functionality change: The only difference is that this found that
we were trying to read past the end of COFF import library but ignoring the
error.
llvm-svn: 199770
I did write a version returning ErrorOr<OwningPtr<Binary> >, but it is too
cumbersome to use without std::move. I will keep the patch locally and submit
when we switch to c++11.
llvm-svn: 199326
If no other operation is specified, 's' becomes an operation instead of an
modifier. The s operation just creates a symbol table. It is the same as
running ranlib.
We assume the archive was created by a sane ar (like llvm-ar or gnu ar) and
if the symbol table is present, then it is current. We use that to optimize
the most common case: a broken build system that thinks it has to run ranlib.
llvm-svn: 187353
This fixes two bugs is lib/Object that the use in llvm-ar found:
* In OS X created archives, the name can be padded with nulls. Strip them.
* In the constructor, remember the first non special member and use that in
begin_children. This makes sure we skip all special members, not just the
first one.
The change to llvm-ar itself consist of
* Using lib/Object for reading archives instead of ArchiveReader.cpp.
* Writing the modified archive directly, instead of creating an in memory
representation.
The old Archive library was way more general than what is needed, as can
be seen by the diffstat of this patch.
Having llvm-ar using lib/Object now opens the way for creating regular symbol
tables for both native objects and bitcode files so that we can use those
archives for LTO.
llvm-svn: 186197
Archive files (.a) can have a symbol table indicating which object
files in them define which symbols. The purpose of this symbol table
is to speed up linking by allowing the linker the read only the .o
files it is actually going to use instead of having to parse every
object's symbol table.
LLVM's archive library currently supports a LLVM specific format for
such table. It is hard to see any value in that now that llvm-ld is
gone:
* System linkers don't use it: GNU ar uses the same plugin as the
linker to create archive files with a regular index. The OS X ar
creates no symbol table for IL files, I assume the linker just parses
all IL files.
* It doesn't interact well with archives having both IL and native objects.
* We probably don't want to be responsible for yet another archive
format variant.
This patch then:
* Removes support for creating and reading such index from lib/Archive.
* Remove llvm-ranlib, since there is nothing left for it to do.
We should in the future add support for regular indexes to llvm-ar for
both native and IL objects. When we do that, llvm-ranlib should be
reimplemented as a symlink to llvm-ar, as it is equivalent to "ar s".
llvm-svn: 184019
Improve performance of iterating over children and accessing the member file
buffer by caching the file size and moving code out to the header.
This also makes getBuffer return a StringRef instead of a MemoryBuffer. Both
fixing a memory leak and removing a malloc.
This takes getBuffer from ~10% of the time in lld to unmeasurable.
llvm-svn: 174272
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.
Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]
llvm-svn: 169131
