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

If we have input without object files, for example if we have only .so
code crashes in checkFlags(), getPicFlags(), getArchFlags() functions.

Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D25237

llvm-svn: 283226

It's better because it's a verb.

llvm-svn: 282763

Previously, all input files were owned by the symbol table.
Files were created at various places, such as the Driver, the lazy
symbols, or the bitcode compiler, and the ownership of new files
was transferred to the symbol table using std::unique_ptr.
All input files were then free'd when the symbol table is freed
which is on program exit.

I think we don't have to transfer ownership just to free all
instance at once on exit.

In this patch, all instances are automatically collected to a
vector and freed on exit. In this way, we no longer have to
use std::unique_ptr.

Differential Revision: https://reviews.llvm.org/D24493

llvm-svn: 281425

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

llvm-svn: 278480

llvm-svn: 278473

llvm-svn: 278392

llvm-svn: 278352

[ELF][MIPS] Take into account combination of EF_MIPS_ARCH and EF_MIPS_MACH flags while checking ISA compatibility

MIPS ISA encoded using two ELF flags: general architecture flag like
EF_MIPS_ARCH_32, EF_MIPS_ARCH_64R6 etc and optional machine variant flag
like EF_MIPS_MACH_4111, EF_MIPS_MACH_OCTEON3 etc. When we check
compatibility between two input files and deduce ELF flags for generated
output we need to take into account both of these flags.

llvm-svn: 278230

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