In many situations, we don't want to exit at the first error even in the
process model. For example, it is better to report all undefined symbols
rather than reporting the first one that the linker picked up randomly.

In order to handle such errors, we don't need to wrap everything with
ErrorOr (thanks for David Blaikie for pointing this out!) Instead, we
can set a flag to record the fact that we found an error and keep it
going until it reaches a reasonable checkpoint.

This idea should be applicable to other places. For example, we can
ignore broken relocations and check for errors after visiting all relocs.

In this patch, I rename error to fatal, and introduce another version of
error which doesn't call exit. That function instead sets HasError to true.
Once HasError becomes true, it stays true, so that we know that there
was an error if it is true.

I think introducing a non-noreturn error reporting function is by itself
a good idea, and it looks to me that this also provides a gradual path
towards lld-as-a-library (or at least embed-lld-to-your-program) without
sacrificing code readability with lots of ErrorOr's.

http://reviews.llvm.org/D16641

llvm-svn: 259069

llvm-svn: 257078

createFiles was doing more than creating files despite its name.
Now these things are moved to a new function.

llvm-svn: 257077

Previously, we handle archive files with --whole-archive this way:
create instances of ArchiveFile, call getMembers to obtain memory
buffers of archive members, and create ObjectFiles for the members.
We didn't call anything except getMembers if --whole-archive was
specified.

I noticed that we didn't actually have to create ArchiveFile instaces
at all for that case. All we need is to get a list of memory buffers
for members, which can be done by a non-member function.

This patch removes getMembers member function from ArchiveFile.
Also removed unnecessary code for memory management.

llvm-svn: 256893

Now that the SymbolTable is templated, we don't need the ELFData class or
multiple inheritance.

llvm-svn: 250005

ArgParser was a class with only one member function, so it didn't
have to be a class.

llvm-svn: 249988

In the linker script, -l and = have the same meaning as in the command line.
In addition to that, if a path is not absolute, the path needs to be searched
from the search paths. This patch implements them.

llvm-svn: 249967

llvm-svn: 249966

Previously, each ArgParser owned a BumpPtrAllocator, and arguments parsed
by an ArgParser would refer strings allocated using the BumpPtrAllocator
only when response files were used. This could cause a subtle bug because
such ownership was not obvious.

This patch moves the ownership from ArgParser to Driver and make the
ownership explicit.

llvm-svn: 249963

llvm-svn: 249962

SymbolTable was not a template class. Instead we had switch-case-based
type dispatch to call desired functions. We had to do that because
SymbolTable was created before we know what ELF type objects had been
passed.

Every time I tried to add a new function to the symbol table, I had to
define a dispatcher which consist of a single switch statement.

It also brought an restriction what the driver can do. For example,
we cannot add undefined symbols before any files are added to the symbol
table. That's because no symbols can be added until the symbol table
knows the ELF type, but when it knows about that, it's too late.

In this patch, the driver makes a decision on what ELF type objects
are being handled. Then the driver creates a SymbolTable object for
an appropriate ELF type.

http://reviews.llvm.org/D13544

llvm-svn: 249902

Parse and apply emulation given with -m option.
Check input files to match ELF type and machine architecture provided with -m.

Differential Revision: http://reviews.llvm.org/D13055

llvm-svn: 249529

Opening a file and dispatching to readLinkerScript() or createFile()
is a common operation. We want to use that at least from Driver and
from LinkerScript. In COFF, we had the same problem. This patch
resolves the problem in the same way as we did for COFF.

Now, if you have a path that you want to open, just call
Driver->addFile(StringRef). That function opens the file and handles
that as if that were given by command line. This function is the
only place we call identify_magic().

llvm-svn: 249023

This linker script parser and evaluator is powerful enough to read
Linux's libc.so, which is (despite its name) a linker script that
contains OUTPUT_FORMAT, GROUP and AS_NEEDED directives.

The parser implemented in this patch is a recursive-descendent one.
It does *not* construct an AST but consumes directives in place and
sets the results to Symtab object, like what Driver is doing.
This should be very fast since less objects are allocated, and
this is also more readable.

http://reviews.llvm.org/D13232

llvm-svn: 248918

llvm-svn: 248877

http://reviews.llvm.org/D13148

llvm-svn: 248575

llvm-svn: 245050

llvm-svn: 244216

The writer is still hard coded to 64 bits le, but with this we can test for
invalid ELF files.

llvm-svn: 243993

Differential Revision: http://reviews.llvm.org/D11188

llvm-svn: 243161

llvm-svn: 242118

This is a direct port of the new PE/COFF linker to ELF.

It can take a single object file and generate a valid executable that executes at the first byte in the text section.

llvm-svn: 242088