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llvm-project/lld/test/mach-o/mh_bundle_header.yaml

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[mach-o] Support linker synthesized mach_header symbols. On darwin in final linked images, the __TEXT segment covers that start of the file. That means in memory a process can see the mach_header (and load commands) for every loaded image in a process. There are APIs that take and return the mach_header addresses as a way to specify a particular loaded image. For completeness, any code can get the address of the mach_header of the image it is in by using &__dso_handle. In addition there are mach-o type specific symbols like __mh_execute_header. The linker needs to supply a definition for any of these symbols if used. But the address the symbol it resolves to is not in any section. Instead it is the address of the start of the __TEXT segment. I needed to make a small change to SimpleFileNode to not override resetNextIndex() because the Driver creates a SimpleFileNode to hold the internal/implicit files that the context/writer can create. For some reason SimpleFileNode overrode resetNextIndex() to do nothing instead of reseting the index (which mach-o needs if the internal file is an archive). llvm-svn: 221822
2014-11-13 06:21:56 +08:00
# RUN: lld -flavor darwin -arch x86_64 %s -bundle -o %t %p/Inputs/libSystem.yaml
# RUN: llvm-nm -m -n %t | FileCheck %s
#
# Test that __mh_bundle_header symbol is available for bundles
#
--- !mach-o
arch: x86_64
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 ]
address: 0x0000000000000000
content: [ 0x55, 0x48, 0x89, 0xE5, 0x31, 0xC0, 0x5D, 0xC3 ]
- segment: __DATA
section: __data
type: S_REGULAR
attributes: [ ]
alignment: 3
address: 0x0000000000000008
content: [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ]
relocations:
- offset: 0x00000000
type: X86_64_RELOC_UNSIGNED
length: 3
pc-rel: false
extern: true
symbol: 2
global-symbols:
- name: _d
type: N_SECT
scope: [ N_EXT ]
sect: 2
value: 0x0000000000000008
- name: _foo
type: N_SECT
scope: [ N_EXT ]
sect: 1
value: 0x0000000000000000
undefined-symbols:
- name: __mh_bundle_header
type: N_UNDF
scope: [ N_EXT ]
value: 0x0000000000000000
...
# CHECK_NOT: __mh_bundle_header
# CHECK: _foo