Commit Graph

5 Commits

Author SHA1 Message Date
Fangrui Song 7c426fb1a6 [ELF] Support INSERT [AFTER|BEFORE] for orphan sections
D43468+D44380 added INSERT [AFTER|BEFORE] for non-orphan sections. This patch
makes INSERT work for orphan sections as well.

`SECTIONS {...} INSERT [AFTER|BEFORE] .foo` does not set `hasSectionCommands`, so the result
will be similar to a regular link without a linker script. The differences when `hasSectionCommands` is set include:

* image base is different
* -z noseparate-code/-z noseparate-loadable-segments are unavailable
* some special symbols such as `_end _etext _edata` are not defined

The behavior is similar to GNU ld:
INSERT is not considered an external linker script.

This feature makes the section layout more flexible. It can be used to:

* Place .nv_fatbin before other readonly SHT_PROGBITS sections to mitigate relocation overflows.
* Disturb the layout to expose address sensitive application bugs.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D74375
2020-02-12 08:21:52 -08:00
George Rimar 8bb8433a1a [LLD][ELF] - Update tests after r352366.
r352366 "[llvm-objdump] - Print LMAs when dumping section headers." changed the format of
llvm-objdump output. We have to update the LLD tests.

llvm-svn: 352372
2019-01-28 15:03:47 +00:00
Fangrui Song e737e75491 [ELF] Change llvm-objdump output for D48472: TEXT DATA -> TEXT
Reviewers: jyknight, Bigcheese, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D48473

llvm-svn: 335404
2018-06-23 00:15:23 +00:00
George Rimar 796684b451 [ELF] - Implement INSERT BEFORE.
This finishes PR35877.

INSERT BEFORE used similar to INSERT AFTER,
it inserts sections before the given target section.

Differential revision: https://reviews.llvm.org/D44380

llvm-svn: 327378
2018-03-13 09:18:11 +00:00
George Rimar 9e2c8a9db1 [ELF] - Support "INSERT AFTER" statement.
This implements INSERT AFTER in a following way:

During reading scripts it collects all insert statements.
After we done and read all files it inserts statements into script commands list.

With that:
* Rest of code does know nothing about INSERT.
* Approach is straightforward and have no visible limitations.
* It is also easy to support INSERT BEFORE (was seen in clang code once).
* Should work for PR35877 and similar cases.

Cons:
* It assumes we have "main" scripts that describes sections.

Differential revision: https://reviews.llvm.org/D43468

llvm-svn: 327003
2018-03-08 14:54:38 +00:00