Commit Graph

8 Commits

Author SHA1 Message Date
Peter Smith 6308ac2254 [ELF] Rename ARM Thunks in anticipation of Range Thunks
The existing names for the ARM and Thumb Thunks highlight their current
use as interworking Thunks. These Thunks can also be used for range
extension Thunks where there is no state change. This change makes the name
more generic so it is suitable for range extension.

Differential Revision: https://reviews.llvm.org/D31605

llvm-svn: 299418
2017-04-04 09:29:36 +00:00
Andre Vieira d74f31bf13 [ARM] Change tests after fixing branch label for Thumb targets
Patch to fix lld tests after my llvm-objdump patch to fix branch labels for
Thumb targets.

Reviewed by: emaste

Differential Revision: https://reviews.llvm.org/D30986

llvm-svn: 298055
2017-03-17 09:37:02 +00:00
Peter Smith 3a52eb0054 [ELF] Use SyntheticSections for Thunks
Thunks are now implemented by redirecting the relocation to the
symbol S, to a symbol TS in a Thunk. The Thunk will transfer control
to S. This has the following implications:
- All the side-effects of Thunks happen within createThunks()
- Thunks are no longer stored in InputSections and Symbols no longer
  need to hold a pointer to a Thunk
- The synthetic Thunk sections need to be merged into OutputSections
    
This implementation is almost a direct conversion of the existing
Thunks with the following exceptions:
- Mips LA25 Thunks are placed before the InputSection that defines
  the symbol that needs a Thunk.
- All ARM Thunks are placed at the end of the OutputSection of the
  first caller to the Thunk.
    
Range extension Thunks are not supported yet so it is optimistically
assumed that all Thunks can be reused.

This is a recommit of r293283 with a fixed comparison predicate as
std::merge requires a strict weak ordering.

Differential revision: https://reviews.llvm.org/D29327

llvm-svn: 293757
2017-02-01 10:26:03 +00:00
Rui Ueyama f20ee9f11a Revert "[ELF][ARM] Use SyntheticSections for Thunks"
This reverts commit r293283 because it broke MSVC build.

llvm-svn: 293352
2017-01-28 00:48:06 +00:00
Peter Smith 5191c6f945 [ELF][ARM] Use SyntheticSections for Thunks
Thunks are now implemented by redirecting the relocation to the
symbol S, to a symbol TS in a Thunk. The Thunk will transfer control
to S. This has the following implications:
- All the side-effects of Thunks happen within createThunks()
- Thunks are no longer stored in InputSections and Symbols no longer
  need to hold a pointer to a Thunk
- The synthetic Thunk sections need to be merged into OutputSections
    
This implementation is almost a direct conversion of the existing
Thunks with the following exceptions:
- Mips LA25 Thunks are placed before the InputSection that defines
  the symbol that needs a Thunk.
- All ARM Thunks are placed at the end of the OutputSection of the
  first caller to the Thunk.
    
Range extension Thunks are not supported yet so it is optimistically
assumed that all Thunks can be reused.

Differential Revision:  https://reviews.llvm.org/D29129

llvm-svn: 293283
2017-01-27 13:10:16 +00:00
Peter Smith 9694376a93 [ELF] Add local mapping symbols to ARM PLT entries
Mapping symbols allow a mapping symbol aware disassembler to
correctly disassemble the PLT when the code immediately prior to the
PLT is Thumb.

To implement this we add a function to add symbols with local
binding to be defined in SyntheticSymbols.

Differential Revision: https://reviews.llvm.org/D28956

llvm-svn: 293044
2017-01-25 10:31:16 +00:00
Peter Collingbourne 628ec9f193 ELF: Place relro sections after non-relro sections in r/w segment.
This is in preparation for my next change, which will introduce a relro
nobits section. That requires that relro sections appear at the end of the
progbits part of the r/w segment so that the relro nobits section can appear
contiguously.

Because of the amount of churn required in the test suite, I'm making this
change separately.

llvm-svn: 291523
2017-01-10 01:21:30 +00:00
Peter Smith 97c6d78f3e [ELF] Add support for thunks to undefined non-weak symbols
In a shared library an undefined symbol is implicitly imported. If the
symbol is called as a function a PLT entry is generated for it. When the
caller is a Thumb b.w a thunk to the PLT entry is needed as all PLT
entries are in ARM state.
    
This change allows undefined symbols to have thunks in the same way that
shared symbols may have thunks.

llvm-svn: 290951
2017-01-04 09:45:45 +00:00