Commit Graph

7 Commits

Author SHA1 Message Date
Fangrui Song ec786906f5 [llvm-objcopy] -O binary: skip empty sections
After SHF_ALLOC sections are ordered by LMA:

* If initial sections are empty, GNU objcopy skips their contents while we
  emit leading zeros. (binary-paddr.test %t4)
* If trailing sections are empty, GNU objcopy skips their contents while we
  emit trailing zeros. (binary-paddr.test %t5)

This patch matches GNU objcopy's behavior. Linkers don't keep p_memsz
PT_LOAD segments. Such empty sections would not have a containing
PT_LOAD and `Section::ParentSegment` might be null if linkers fail to
optimize the file offsets (lld D79254).

In particular, without D79254, the arm Linux kernel's multi_v5_defconfig
depends on this behavior: in `vmlinux`, an empty .text_itcm is mapped at
a very high address (0xfffe0000) but the kernel does not expect
`objcopy -O binary` to create a very large `arch/arm/boot/Image`
(0xfffe0000-0xc0000000 ~= 1GiB). See https://bugs.llvm.org/show_bug.cgi?id=45632

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D79229
2020-05-01 14:25:37 -07:00
Georgii Rymar b236b4cb43 [yaml2obj] - Set a default value for `PAddr` property of a program header to a value of `VAddr`
`PAddr` corresponds to `p_paddr` of a program header, which is the segment's physical
address for systems in which physical addressing is relevant. `p_paddr` is often equal
to `p_vaddr`, which is the virtual address of a segment.

This patch changes the default for `PAddr` from 0 to a value of `VAddr`.

Differential revision: https://reviews.llvm.org/D76131
2020-03-14 17:44:57 +03:00
Fangrui Song d28c6d51d1 [llvm-objcopy][ELF] -O binary: use LMA instead of sh_offset to decide where to write section contents
.text sh_address=0x1000 sh_offset=0x1000
.data sh_address=0x3000 sh_offset=0x2000

In an objcopy -O binary output, the distance between two sections equal
their LMA differences (0x3000-0x1000), instead of their sh_offset
differences (0x2000-0x1000). This patch changes our behavior to match
GNU.

This rule gets more complex when the containing PT_LOAD has
p_vaddr!=p_paddr. GNU objcopy essentially computes
sh_offset-p_offset+p_paddr for each candidate section, and removes the
gap before the first address.

Added tests to binary-paddr.test to catch the compatibility problem.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D71035
2019-12-15 21:45:25 -08:00
Kai Nacke 42b7cd5830 [Tests] Output of od can be lower or upper case (llvm-objcopy/yaml2obj).
The command `od -t x` is used to dump data in hex format.
The LIT tests assumes that the hex characters are in lowercase.
However, there are also platforms which use uppercase letter.

To solve this issue the tests are updated to use the new
`--ignore-case` option of FileCheck.

Reviewers: Bigcheese, jakehehrlich, rupprecht, espindola, alexshap, jhenderson

Differential Revision: https://reviews.llvm.org/D68693

llvm-svn: 374547
2019-10-11 12:50:57 +00:00
Dmitri Gribenko a89e5a41ec Revert "[Tests] Output of od can be lower or upper case (llvm-objcopy/yaml2obj)."
This reverts commit r374343. It broke tests:
http://lab.llvm.org:8011/builders/clang-x86_64-debian-fast/builds/19066

llvm-svn: 374358
2019-10-10 14:26:54 +00:00
Kai Nacke 819f01d917 [Tests] Output of od can be lower or upper case (llvm-objcopy/yaml2obj).
The command `od -t x` is used to dump data in hex format.
The LIT tests assumes that the hex characters are in lowercase.
However, there are also platforms which use uppercase letter.

To solve this issue the tests are updated to use the new
`--ignore-case` option of FileCheck.

Reviewers: Bigcheese, jakehehrlich, rupprecht, espindola, alexshap, jhenderson

Differential Revision: https://reviews.llvm.org/D68693

llvm-svn: 374343
2019-10-10 13:24:00 +00:00
Alexander Shaposhnikov 6e4dc6f23f [llvm-objcopy] Move elf-specific tests into subfolder
In this diff the elf-specific tests are moved into the subfolder llvm-objcopy/ELF
(the change was discussed in the comments on https://reviews.llvm.org/D54674).
A separate code reivew wasn't sent for this change 
since Phabricator is failing to create such a large diff.

Test plan: 
make check-all
make check-llvm-tools
make check-llvm-tools-llvm-objcopy

llvm-svn: 347958
2018-11-30 05:43:39 +00:00