Changes in sections-padding.s

bb7d2b17 - [LLD][ELF] - Disambiguate "=fillexp" with a primary expression to allow =0x90 /DISCARD/

Sun, 16 Feb 2020 11:17:26 +0000

[LLD][ELF] - Disambiguate "=fillexp" with a primary expression to allow =0x90 /DISCARD/Fixes https://bugs.llvm.org/show_bug.cgi?id=44903It is about the following case:```SECTIONS { .foo : { *(.foo) } =0x90909090 /DISCARD/ : { *(.bar) }}```Here while parsing the fill expression we treated the"/" of "/DISCARD/" as operator.With this change, suggested by Fangrui Song, we donot allow expressions with operators (e.g. "0x1100 + 0x22")that are not wrapped into round brackets. It should notbe an issue for users, but helps to resolve parsing ambiguity.Differential revision: https://reviews.llvm.org/D74687 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

f0374e7d - [test] lld/test/: change llvm-objdump single-dash long options to double-dash options

Mon, 16 Mar 2020 00:47:44 +0000

[test] lld/test/: change llvm-objdump single-dash long options to double-dash options List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

81cebfd0 - [ELF][test] Change -o %t to -o /dev/null if the output is not needed

Thu, 13 Feb 2020 05:48:45 +0000

[ELF][test] Change -o %t to -o /dev/null if the output is not needed List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

c44a23f8 - [LLD][ELF] - Linkerscript: fix FILL() expressions handling.

Wed, 10 Jul 2019 14:36:48 +0000

[LLD][ELF] - Linkerscript: fix FILL() expressions handling.D64130 introduced a bug described in the following message:https://reviews.llvm.org/D64130#1571560The problem can happen with the following script:SECTIONS { .out : {... FILL(0x10101010) *(.aaa)...}The current code tries to read (0x10101010) as an expression anddoes not break when meets *, what results in a script parsing error.In this patch, I verify that FILL command's expression always wrapped in ().And at the same time = expression can be both wrapped or unwrapped.I checked it matches to bfd/gold.Differential revision: https://reviews.llvm.org/D64476llvm-svn: 365635 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

0810f16f - [LLD][ELF] - Linkerscript: add a support for expressions for section's filling

Thu, 04 Jul 2019 14:17:31 +0000

[LLD][ELF] - Linkerscript: add a support for expressions for section's fillingImagine the script:.section: {...} = FILL_EXPRLLD assumes that FILL_EXPR is a number, and does not allowit to be an expression. Though that is allowed by specification:https://sourceware.org/binutils/docs-2.32/ld/Output-Section-Fill.htmlThis patch adds a support for cases when FILL_EXPR is simple math expression.Fixes https://bugs.llvm.org/show_bug.cgi?id=42482.Differential revision: https://reviews.llvm.org/D64130llvm-svn: 365143 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

9d9a6637 - [ELF] Recommit r299635 to pad x86 executable sections with 0xcc

Fri, 07 Apr 2017 10:36:42 +0000

[ELF] Recommit r299635 to pad x86 executable sections with 0xccThis follows r299748 which fixed a latent bug the original commit exposed.llvm-svn: 299755 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

d9831807 - Revert r299635 because it exposed a latent bug.

Thu, 06 Apr 2017 15:22:58 +0000

Revert r299635 because it exposed a latent bug.llvm-svn: 299655 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

8dd4c06a - [ELF] Pad x86 executable sections with 0xcc int3 instructions

Thu, 06 Apr 2017 09:29:08 +0000

[ELF] Pad x86 executable sections with 0xcc int3 instructionsExecutable sections should not be padded with zero by default. On somearchitectures, 0x00 is the start of a valid instruction sequence, so can confusedisassembly between InputSections (and indeed the start of the next InputSectionin some situations). Further, in the case of misjumps into padding, padding maystart to be executed silently.On x86, the "0xcc" byte represents the int3 trap instruction. It is a singlebyte long so can serve well as padding. This change switches x86 (and x86_64) touse this value for padding in executable sections, if no linker script directiveoverrides it. It also puts the behaviour into place making it easy to change thebehaviour of other targets when desired. I do not know the relevant instructionsequences for trap instructions on other targets however, so somebody should addthis separately.Because the old behaviour simply wrote padding in the whole section beforeoverwriting most of it, this change also modifies the padding algorithm to writepadding only where needed. This in turn has caused a small behaviour change withregards to what values are written via Fill commands in linker scripts, bringingit into line with ld.bfd. The fill value is now written starting from the end ofthe previous block, which means that it always starts from the first byte of thefill, whereas the old behaviour meant that the padding sometimes started mid-waythrough the fill value. See the test changes for more details.Reviewed by: ruiuDifferential Revision: https://reviews.llvm.org/D30886Bugzilla: http://bugs.llvm.org/show_bug.cgi?id=32227llvm-svn: 299635 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

7185a1ac - [ELF] - Support optional comma after output section command.

Tue, 17 Jan 2017 15:32:12 +0000

[ELF] - Support optional comma after output section command.I found this when tried to link linux kernel with LLD:https://github.com/torvalds/linux/blob/master/arch/x86/entry/vdso/vdso-layout.lds.S#L86Output section command can have optional comma at the end:.text : { *(.text*) } :text =0x90909090,It was documented about 3 years ago for binutils:https://sourceware.org/ml/binutils/2014-04/msg00045.htmlDifferential revision: https://reviews.llvm.org/D28803llvm-svn: 292225 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

4ebc5620 - [ELF] - Linkerscript: accept space between '=' and expression in section filler.

Fri, 23 Sep 2016 13:29:20 +0000

[ELF] - Linkerscript: accept space between '=' and expression in section filler.Previously we failed to parse next scripts because disalloweda space between filler value and '=': .text : {... } :text = 0x9090Differential revision: https://reviews.llvm.org/D24831llvm-svn: 282248 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

1b87995f - Make tests less dependent on the exact layout.

Tue, 20 Sep 2016 15:08:24 +0000

Make tests less dependent on the exact layout.In most cases that means just not checking the address when we don'tneed it.For some tests it is easier to just set . to a known value.llvm-svn: 281976 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

ff1f29e0 - [ELF] - Linkerscript: implemented FILL command as alias for =fillexpr

Tue, 06 Sep 2016 13:51:57 +0000

[ELF] - Linkerscript: implemented FILL command as alias for =fillexprPatch implements FILL just as alias for =fillexpr. This allows to make implementation much shorted and simpler than D24186.Differential revision: https://reviews.llvm.org/D24227llvm-svn: 280708 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s

66ba9f08 - Remove useless file prefix.

Fri, 02 Sep 2016 20:40:53 +0000

Remove useless file prefix.Differential Revision: https://reviews.llvm.org/D24207llvm-svn: 280540 List of files: /llvm-project-15.0.7/lld/test/ELF/linkerscript/sections-padding.s