llvm-svn: 290215

This handles all the corner cases if setting a section address:

- If the address is too low, we cannot allocate the program headers.
- If the load address is lowered, we have to do that before finalize

This also shares some code with the linker script since it was already
hitting similar cases.

This is used by the freebsd boot loader. It is not clear if we need to
support this with a non binary output, but it is not as bad as I was
expecting.

llvm-svn: 290136

llvm-svn: 290115

Differential revision: https://reviews.llvm.org/D27097

llvm-svn: 288114

The disadvantage is that we use uint64_t instad of uint32_t for some
value in 32 bit files. The advantage is a substantially simpler code,
faster builds and less code duplication.

llvm-svn: 286414

In short the patch introduces support for linking object file conform
MIPS N32 ABI [1]. This ABI is similar to N64 ABI but uses 32-bit
pointer size.

The most non-trivial requirement of this ABI is one more relocation
packing format. N64 ABI puts multiple relocation type into the single
relocation record. The N32 ABI uses series of successive relocations
with the same offset for this purpose. In this patch, new function
`mergeMipsN32RelTypes` handle this case and "convert" N32 relocation to
the N64 relocation so the rest of the code keep unchanged.

For now, linker does not support series of relocations applied to sections
without SHF_ALLOC bit. Probably later I will add the support or insert
some sort of assert into the `relocateNonAlloc` routine to catch this
case.

[1] ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/MIPS-N32-ABI-Handbook.pdf

Differential revision: https://reviews.llvm.org/D26298

llvm-svn: 286052

llvm-svn: 285996

Previously, we have a lot of BumpPtrAllocators, but all these
allocators virtually have the same lifetime because they are
not freed until the linker finishes its job. This patch aggregates
them into a single allocator.

Differential revision: https://reviews.llvm.org/D26042

llvm-svn: 285452

llvm-svn: 284705

Previously, we supported only SHF_COMPRESSED sections because it's
new and it's the ELF standard. But there are object files compressed
in the GNU style out there, so we had to support it.

Sections compressed in the GNU style start with ".zdebug_" and
contain different headers than the ELF standard's one. In this
patch, getRawCompressedData is responsible to handle it.

A tricky thing about GNU-style compressed sections is that we have
to rename them when creating output sections. ".zdebug_" prefix
implies the section is compressed. We need to rename ".zdebug_"
".debug" because our output sections are not compressed.
We do that in this patch.

llvm-svn: 284068

Differential revision: https://reviews.llvm.org/D25232

llvm-svn: 283307

Differential revision: https://reviews.llvm.org/D24340

llvm-svn: 281024

This section supersedes .reginfo and .MIPS.options sections. But for now
we have to support all three sections for ABI transition period.

llvm-svn: 278482

This patch is to not instantiate DynSymTab and DynStrTab if the
output is not a dynamic output.

llvm-svn: 278095

The SymbolTable is always accessible as Symtab<ELFT>::X,
so no need to pass it as an argument.

llvm-svn: 278091

Previously, we incrementally updated the reuslting flag as we check
file flags, so it was not very clear who is updating what flags.
This patch makes them pure functions -- that has no side effect and
don't update arguments to improve readability.

Now each function construct a patial result, and all resutls are then
bitwise-OR'ed to construct the final result.

This patch also creates a new file, Mips.cpp, to move all these
MIPS functions to a separate file.

Differential Revision: https://reviews.llvm.org/D23249

llvm-svn: 278042

llvm-svn: 276868

llvm-svn: 276774

Because the file from which an input section is created can be
obtained using getFile().

llvm-svn: 276702

This change simplifies interaction between Writer and the linker script
because we can make needsInterpSection() a file-scope function.

llvm-svn: 276261

llvm-svn: 276165

llvm-svn: 275972

llvm-svn: 275965

Creating sections on linkerscript side requires some methods
that can be reused if are exported from writer.

Patch implements that change.

Differential revision: http://reviews.llvm.org/D20104

llvm-svn: 275162

llvm-svn: 268286

llvm-svn: 262159

Section garbage collection is a feature to remove unused sections
from outputs. Unused sections are sections that cannot be reachable
from known GC-root symbols or sections. Naturally the feature is
implemented as a mark-sweep garbage collector.

In this patch, I added Live bit to InputSectionBase. If and only
if Live bit is on, the section will be written to the output.
Starting from GC-root symbols or sections, a new function, markLive(),
visits all reachable sections and sets their Live bits. Writer then
ignores sections whose Live bit is off, so that such sections are
excluded from the output.

This change has small negative impact on performance if you use
the feature because making sections means more work. The time to
link Clang changes from 0.356s to 0.386s, or +8%.

It reduces Clang size from 57,764,984 bytes to 55,296,600 bytes.
That is 4.3% reduction.

http://reviews.llvm.org/D13950

llvm-svn: 251043

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

llvm-svn: 249586

llvm-svn: 245050

llvm-svn: 244697

Various parameters are passed implicitly using Config global variable
already. Output file path is no different from others, so there was no
special reason to handle that differnetly.

This patch changes the signature of writeResult(SymbolTable *, StringRef)
to writeResult(SymbolTable *).

llvm-svn: 244180

We are using Writer more like a function instead of a class.
This patch makes it a function to simplify the interface.
All details of Writer class is now hidden from other parts of the linker.

llvm-svn: 244169

The others we have in sight are
* common symbols.
* entries in SHF_MERGE sections.

They will have a substantially different treatment. It is not clear if it is
worth it putting them all in a single list just to dispatch based on the kind on
the other side.

I hope to implement common symbols soon, and then we will be in a position
to have a concrete discussion. For now this is simpler for the the implemented
features.

llvm-svn: 244042

It was already using just code that is common to all object files.

llvm-svn: 243985

llvm-svn: 243579

llvm-svn: 243506

llvm-svn: 243231

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

llvm-svn: 243161

llvm-svn: 242118