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llvm-project/lld/test/mach-o/arm-shims.yaml

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[mach-o] Add Pass to create are shim Atoms for ARM interworking. Arm code has two instruction encodings "thumb" and "arm". When branching from one code encoding to another, you need to use an instruction that switches the instruction mode. Usually the transition only happens at call sites, and the linker can transform a BL instruction in BLX (or vice versa). But if the compiler did a tail call optimization and a function ends with a branch (not branch and link), there is no pc-rel BX instruction. The ShimPass looks for pc-rel B instructions that will need to switch mode. For those cases it synthesizes a shim which does the transition, then modifies the original atom with the B instruction to target to the shim atom. llvm-svn: 219655
2014-10-14 09:51:42 +08:00
# RUN: lld -flavor darwin -arch armv7 %s -dylib %p/Inputs/libSystem.yaml -o %t
# RUN: macho-dump --dump-section-data %t | FileCheck %s
#
# Test b from arm to thumb or vice versa has shims added.s
#
#
--- !mach-o
arch: armv7
file-type: MH_OBJECT
flags: [ MH_SUBSECTIONS_VIA_SYMBOLS ]
sections:
- segment: __TEXT
section: __text
type: S_REGULAR
attributes: [ S_ATTR_PURE_INSTRUCTIONS, S_ATTR_SOME_INSTRUCTIONS ]
alignment: 2
address: 0x0000000000000000
content: [ 0x00, 0xBF, 0xFF, 0xF7, 0xFE, 0xEF, 0xFF, 0xF7,
0xFB, 0xBF, 0x00, 0x00, 0x00, 0xF0, 0x20, 0xE3,
0xFA, 0xFF, 0xFF, 0xFA, 0xF9, 0xFF, 0xFF, 0xEA ]
relocations:
- offset: 0x00000014
type: ARM_RELOC_BR24
length: 2
pc-rel: true
extern: true
symbol: 3
- offset: 0x00000010
type: ARM_RELOC_BR24
length: 2
pc-rel: true
extern: true
symbol: 3
- offset: 0x00000006
type: ARM_THUMB_RELOC_BR22
length: 2
pc-rel: true
extern: true
symbol: 2
- offset: 0x00000002
type: ARM_THUMB_RELOC_BR22
length: 2
pc-rel: true
extern: true
symbol: 2
global-symbols:
- name: _a1
type: N_SECT
scope: [ N_EXT ]
sect: 1
value: 0x000000000000000C
- name: _t1
type: N_SECT
scope: [ N_EXT ]
sect: 1
desc: [ N_ARM_THUMB_DEF ]
value: 0x0000000000000000
undefined-symbols:
- name: _a2
type: N_UNDF
scope: [ N_EXT ]
value: 0x0000000000000000
- name: _t2
type: N_UNDF
scope: [ N_EXT ]
value: 0x0000000000000000
--- !mach-o
arch: armv7
file-type: MH_OBJECT
flags: [ MH_SUBSECTIONS_VIA_SYMBOLS ]
sections:
- segment: __TEXT
section: __text
type: S_REGULAR
attributes: [ S_ATTR_PURE_INSTRUCTIONS, S_ATTR_SOME_INSTRUCTIONS ]
alignment: 2
address: 0x0000000000000000
content: [ 0x00, 0xBF, 0xFF, 0xF7, 0xFE, 0xEF, 0xFF, 0xF7,
0xFB, 0xBF, 0x00, 0x00, 0x00, 0xF0, 0x20, 0xE3,
0xFA, 0xFF, 0xFF, 0xFA, 0xF9, 0xFF, 0xFF, 0xEA ]
relocations:
- offset: 0x00000014
type: ARM_RELOC_BR24
length: 2
pc-rel: true
extern: true
symbol: 3
- offset: 0x00000010
type: ARM_RELOC_BR24
length: 2
pc-rel: true
extern: true
symbol: 3
- offset: 0x00000006
type: ARM_THUMB_RELOC_BR22
length: 2
pc-rel: true
extern: true
symbol: 2
- offset: 0x00000002
type: ARM_THUMB_RELOC_BR22
length: 2
pc-rel: true
extern: true
symbol: 2
global-symbols:
- name: _a2
type: N_SECT
scope: [ N_EXT ]
sect: 1
value: 0x000000000000000C
- name: _t2
type: N_SECT
scope: [ N_EXT ]
sect: 1
desc: [ N_ARM_THUMB_DEF ]
value: 0x0000000000000000
undefined-symbols:
- name: _a1
type: N_UNDF
scope: [ N_EXT ]
value: 0x0000000000000000
- name: _t1
type: N_UNDF
scope: [ N_EXT ]
value: 0x0000000000000000
...
# CHECK: (('section_name', '__text\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
# CHECK: ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
# CHECK: ('_section_data', '00bf00f0 10e800f0 19b80000 00f020e3 000000fa 0f0000ea 00bffff7 f8ef00f0 07b80000 00f020e3 f4fffffa 050000ea dff804c0 ff446047 d4ffffff dff804c0 ff446047 e0ffffff 04c09fe5 0cc08fe0 1cff2fe1 adffffff 04c09fe5 0cc08fe0 1cff2fe1 b5ffffff')
# When we get a good mach-o disassembler the above __text section content check can be change to be symbolic.
# Input file one:
#
# .align 2
# .code 16
# .globl _t1
# .thumb_func _t1
#_t1:
# nop
# blx _a2
# b _a2
#
# .code 32
# .align 2
# .globl _a1
#_a1:
# nop
# blx _t2
# b _t2
# Input file two:
#
# .align 2
# .code 16
# .globl _t2
# .thumb_func _t2
#_t2:
# nop
# blx _a1
# b _a1
#
# .code 32
# .align 2
# .globl _a2
#_a2:
# nop
# blx _t1
# b _t1