`getLineNumber` is both imprecise (when `INCLUDE` is used) and
inefficient (see https://reviews.llvm.org/D104137). Track line number
precisely now that we have `struct Buffer` abstraction from #100493.
https://reviews.llvm.org/D44780 implemented rudimentary support for
OVERLAY. The start address and `AT(ldaddr)` in `OVERLAY [start] :
[NOCROSSREFS] [AT ( ldaddr )]` are not optional.
In addition, there are two issues:
* When the start address is `.`, subsequent sections don't share the
address of the first overlay section.
* When the first overlay section is empty and discardable, `p_paddr` is
incorrectly zero. This is because a discarded section has a zero
address, causing `prev->getLMA() + prev->size` where `prev` refers to
the first section to evaluate to zero.
This patch supports optional start address and LMA and fix the issues.
Close#77265
Pull Request: https://github.com/llvm/llvm-project/pull/77272
Also test two issues:
* When the start address is `.`, subsequent sections don't share the
address of the first overlay section.
* When the first overlay section is empty and discardable, `p_paddr` is
incorrectly zero. This is because a discarded section has a zero
address, causing `prev->getLMA() + prev->size` where `prev` refers to
the first section to evaluate to zero.
This essentially drops the change by r288021 (discussed with Georgii Rymar
and Peter Smith and noted down in the release note of lld 10).
GNU ld>=2.31 enables -z separate-code by default for Linux x86. By
default (in the absence of a PHDRS command) a readonly PT_LOAD is
created, which is different from its traditional behavior.
Not emulating GNU ld's traditional behavior is good for us because it
improves code consistency (we create a readonly PT_LOAD in the absence
of a SECTIONS command).
Users can add --no-rosegment to restore the previous behavior (combined
readonly and read-executable sections in a single RX PT_LOAD).
Also change some options that have different semantics (cause confusion) in llvm-readelf mode:
-s => -S
-t => --symbols
-sd => --section-data
llvm-svn: 359651
This is PR36768.
Linker script OVERLAYs are described in 4.6.9. Overlay Description of the spec:
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/4/html/Using_ld_the_GNU_Linker/sections.html
They are used to allow output sections which have different LMAs but the same VAs
and used for embedded programming.
Currently, LLD restricts overlapping of sections and that seems to be the most desired
behaviour for defaults. My thoughts about possible approaches for PR36768 are on the bug page,
this patch implements OVERLAY keyword and allows VAs overlapping for sections that within the overlay.
Differential revision: https://reviews.llvm.org/D44780
llvm-svn: 335714
