Commit Graph

7 Commits

Author SHA1 Message Date
Fangrui Song 3d87323a7e [ELF] Make non-writable non-executable PROGBITS sections closer to .text
This generalizes the old heuristic placing SHT_DYNSYM SHT_DYNSTR first in the readonly SHF_ALLOC segment.

Reviewers: espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D48406

llvm-svn: 335674
2018-06-26 22:13:32 +00:00
Fangrui Song 68fa4e8c34 [ELF] Assign RF_EXEC rank even if --no-rosegment or SECTIONS command is used
Summary:
Currently when --no-rosegment is specified or a linker script with SECTIONS command is used,
.rodata (A) .text (AX) are assigned the same rank and .rodata may be placed after .text .
This increases the gap between .text and .bss and can cause pc-relative relocation overflow (e.g. gcc crtbegin.o crtbegin.S have R_X86_64_PC32 relocation from .text to .bss).

This patch makes SingleRoRx affect only segment layout, not section layout. As a consequence, .rodata will be placed before .text regardless of SingleRoRx.

Reviewers: espindola, ruiu, grimar, echristo, javed.absar

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D48405

llvm-svn: 335627
2018-06-26 17:04:47 +00:00
Fangrui Song 65c50074c2 [ELF] readobj -elf-output-style=GNU -> readelf
Style change for consistency. NFC

llvm-svn: 335494
2018-06-25 16:49:52 +00:00
Han Shen b56030ee9e [lld] Mitigate relocation overflow [part 1 of 2].
This CL places .dynsym and .dynstr at the beginning of SHF_ALLOC
sections. We do this to mitigate the possibility that huge .dynsym and
.dynstr sections placed between ro-data and text sections cause
relocation overflow.

Differential Revision: https://reviews.llvm.org/D45788

llvm-svn: 332374
2018-05-15 17:02:35 +00:00
George Rimar 4c9ae67bb7 [ELF] - Revert of: r332038, r332054, r332060, r332061, r332062, r332063
This reverts "Mitigate relocation overflow [part 1 of 2]." and the following commits which
were trying to fix the bots.

At the moment of r332082, bots are still failing and we need to find the reason of test case breakages first of all.
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast/builds/17042/steps/test/logs/stdio
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/29845/steps/test/logs/stdio

llvm-svn: 332085
2018-05-11 08:11:25 +00:00
Han Shen 6c0881c3cd Mitigate relocation overflow [part 1 of 2].
This CL is to mitigate R_X86_64_PC32 relocation overflow problems for huge binaries that has near 4G allocated sections.

By examining those binaries, there're 2 issues contributes to the problem:
1). huge ".dynsym" and ".dynstr" stands in the way between .rodata and .text
2). _init_array_start/end are placed at 0 if no ".init_array" presents, this causes .text relocation against them become more prone to overflow.

This CL addresses 1st problem (the 2nd will be addressed in another CL.) by assigning a smaller sortrank to .dynsym and .dynstr thus they no longer stand in between.

llvm-svn: 332038
2018-05-10 20:44:42 +00:00
George Rimar f95e7c6f7a [ELF] - Rename test cases to *.test.
This is a follow-up for r327410.

llvm-svn: 327416
2018-03-13 16:02:45 +00:00