llvm-project

Commit Graph

Author	SHA1	Message	Date
Peter Smith	a8656c62f5	[ELF] Add support for Armv5 and Armv6 compatible Thunks Older Arm architectures do not support the MOVT and MOVW instructions so we must use an alternative sequence of instructions to transfer control to the destination. Assuming at least Armv5 this patch adds support for Thunks that load or add to the program counter. Note that there are no Armv5 Thumb Thunks as there is no Thumb branch instruction in Armv5 that supports Thunks. These thunks will not work for Armv4t (arm7tdmi) as this architecture cannot change state from using the LDR or ADD instruction. Differential Revision: https://reviews.llvm.org/D50077 llvm-svn: 340160	2018-08-20 09:37:50 +00:00
Peter Collingbourne	4653b0021e	Add missing REQUIRES: arm. llvm-svn: 328847	2018-03-29 23:08:32 +00:00
Peter Collingbourne	015d30c807	ELF: Add support for short thunks on ARM. A short thunk uses a direct branch (b or b.w) instruction, and is used when the target has the same thumbness as the thunk and is within direct branch range (32MB for ARM, 16MB for Thumb-2). Reduces the size of Chromium for Android's .text section by around 160KB. Differential Revision: https://reviews.llvm.org/D44963 llvm-svn: 328846	2018-03-29 22:43:52 +00:00

Author

SHA1

Message

Date

Peter Smith

a8656c62f5

[ELF] Add support for Armv5 and Armv6 compatible Thunks

Older Arm architectures do not support the MOVT and MOVW instructions so we
must use an alternative sequence of instructions to transfer control to the
destination.

Assuming at least Armv5 this patch adds support for Thunks that load or add
to the program counter. Note that there are no Armv5 Thumb Thunks as there
is no Thumb branch instruction in Armv5 that supports Thunks. These thunks
will not work for Armv4t (arm7tdmi) as this architecture cannot change state
from using the LDR or ADD instruction.

Differential Revision: https://reviews.llvm.org/D50077

llvm-svn: 340160

2018-08-20 09:37:50 +00:00

Peter Collingbourne

4653b0021e

Add missing REQUIRES: arm.

llvm-svn: 328847

2018-03-29 23:08:32 +00:00

Peter Collingbourne

015d30c807

ELF: Add support for short thunks on ARM.

A short thunk uses a direct branch (b or b.w) instruction, and is used
when the target has the same thumbness as the thunk and is within
direct branch range (32MB for ARM, 16MB for Thumb-2). Reduces the
size of Chromium for Android's .text section by around 160KB.

Differential Revision: https://reviews.llvm.org/D44963

llvm-svn: 328846

2018-03-29 22:43:52 +00:00

3 Commits