llvm-project

Commit Graph

Author	SHA1	Message	Date
Rafael Espindola	f846ce259a	Fix weak symbols on arm and aarch64. Given .weak target .global _start _start: b target The intention is that the branch goes to the instruction after the branch, effectively turning it on a nop. The branch adds the runtime PC, but we were adding it statically too. I noticed the oddity by inspection, but llvm-objdump seems to agree, since it now prints things like: b #-4 <_start+0x4> llvm-svn: 305212	2017-06-12 18:05:01 +00:00
Rafael Espindola	d2a1b944bc	Don't check the raw bits in tests. It is not needed since we have the disassemble. llvm-svn: 305096	2017-06-09 18:07:34 +00:00
Peter Smith	8339bbd759	[ELF] ARM and AArch64 undefined weak reference values The ARM 32 and 64-bit ABI does not use 0 for undefined weak references that are used in PC relative relocations. In particular: - A branch relocation to an undefined weak resolves to the next instruction. Effectively making the branch a no-op - In all other cases the symbol resolves to the place so that S + A - P resolves to A. Differential Revision: https://reviews.llvm.org/D26240 llvm-svn: 286353	2016-11-09 10:22:29 +00:00

Author

SHA1

Message

Date

Rafael Espindola

f846ce259a

Fix weak symbols on arm and aarch64.

Given

.weak target
 .global _start
_start:
 b target

The intention is that the branch goes to the instruction after the
branch, effectively turning it on a nop.  The branch adds the runtime
PC, but we were adding it statically too.

I noticed the oddity by inspection, but llvm-objdump seems to agree,
since it now prints things like:

b       #-4 <_start+0x4>

llvm-svn: 305212

2017-06-12 18:05:01 +00:00

Rafael Espindola

d2a1b944bc

Don't check the raw bits in tests.

It is not needed since we have the disassemble.

llvm-svn: 305096

2017-06-09 18:07:34 +00:00

Peter Smith

8339bbd759

[ELF] ARM and AArch64 undefined weak reference values

The ARM 32 and 64-bit ABI does not use 0 for undefined weak references
that are used in PC relative relocations. In particular:
- A branch relocation to an undefined weak resolves to the next
  instruction. Effectively making the branch a no-op
- In all other cases the symbol resolves to the place so that S + A - P
  resolves to A.

Differential Revision: https://reviews.llvm.org/D26240

llvm-svn: 286353

2016-11-09 10:22:29 +00:00

3 Commits