Commit Graph

758 Commits

Author SHA1 Message Date
Rafael Espindola 40f46bc3e6 Delete unused variable.
llvm-svn: 330978
2018-04-26 19:21:07 +00:00
Rafael Espindola ab0cce5f1f Replace SharedSymbols with Defined when creating copy relocations.
This is slightly simpler to read IMHO. Now if a symbol has a position
in the file, it is Defined.

The main motivation is that with this a SharedSymbol doesn't need a
section, which reduces the size of SymbolUnion.

With this the peak allocation when linking chromium goes from 568.1 to
564.2 MB.

llvm-svn: 330966
2018-04-26 17:58:58 +00:00
George Rimar d30a78b3fe [ELF] - Eliminate the AssertCommand.
Currently, LLD supports ASSERT as a separate command.

We support two forms now.

Assign expression-form: . = ASSERT(0x100)
(old GNU ld required it and some scripts in the wild are still using
something like . = ASSERT((_end - _text <= (512 * 1024 * 1024)), "kernel image bigger than KERNEL_IMAGE_SIZE");

Nowadays above is not a mandatory form and command-like form is commonly used:
ASSERT(<expr>, "text);

The return value of the ASSERT is Dot. That was implemented in D30171.
It looks like (2) is just a short version of (1) then.

GNU ld does *not* list ASSERT as a SECTIONS command:
https://sourceware.org/binutils/docs/ld/SECTIONS.html#SECTIONS

Given above we probably can change ASSERT to be an assignment to Dot. 
That makes the rest of the code much simpler. Patch do that.

Differential revision: https://reviews.llvm.org/D45434

llvm-svn: 330814
2018-04-25 11:16:31 +00:00
George Rimar 0029f21482 [ELF] - Stop setting OutSecOff too early.
Currently LLD sets OutSecOff in addSection for input sections.
That is a fake offset (just a rude approximation to remember the order), 
used for sorting SHF_LINK_ORDER sections
(see resolveShfLinkOrder, compareByFilePosition).

There are 2 problems with such approach:

1. We currently change and reuse Size field as a value assigned. Changing size is
not good because leads to bugs. Currently, SIZEOF(.bss) for empty .bss returns 2
because we add two empty synthetic sections and increase size twice by 1. 
(See PR37011: https://bugs.llvm.org/show_bug.cgi?id=37011)

2. Such approach simply does not work when --symbol-ordering-file is involved,
because processing of the ordering file might break the initial section order.

This fixes PR37011.

Differential revision: https://reviews.llvm.org/D45368

llvm-svn: 329560
2018-04-09 13:01:50 +00:00
George Rimar e88b76a989 [ELF] - Reveal more information in -Map file about assignments.
Currently, LLD print symbol assignment commands to the map file,
but it does not do that for assignments that are outside of the section
descriptions. Such assignments can affect the layout though.

The patch implements the following:

* Teaches LLD to print symbol assignments outside of section declaration.
* Teaches LLD to print PROVIDE/HIDDEN/PROVIDE hidden commands.

In case when symbol is not provided, nothing will be printed.

Differential revision: https://reviews.llvm.org/D44894

llvm-svn: 329272
2018-04-05 11:25:58 +00:00
George Rimar 4d2740c6ed [ELF] - Cleanup. NFCI.
Rename field, added comments.

This is splitted from the D44894. 
Requested to be committed as independent cleanup.

llvm-svn: 329162
2018-04-04 09:39:05 +00:00
Rafael Espindola 9c2c938521 Reduce code duplication a bit.
Thanks to George Rimar for pointing it out.

llvm-svn: 328571
2018-03-26 18:55:33 +00:00
Rafael Espindola f065390f6c Reduce code duplication a bit. NFC
llvm-svn: 328569
2018-03-26 18:49:31 +00:00
George Rimar a6ce78ece1 This is PR36799.
Currently, we might have a bug with scripts like below:

.foo : ALIGN(8) 
{
  *(.foo)
} > ram
because do not expand the memory region when doing ALIGN.

This might result in file range overlaps. The patch fixes the issue.

Differential revision: https://reviews.llvm.org/D44730

llvm-svn: 328479
2018-03-26 08:58:16 +00:00
George Rimar d8281379f9 [ELF] - Do not ignore discarding of .rela.plt/.rela.dyn, allow doing custom layout for them.
Currently when we build input sections list in linker script
we ignore all rel[a] sections. That was done to support
scripts like .rela.dyn : { *(.rela.data) } for emit relocs.

Though as a result following scripts were also silently ignored:

/DISCARD/ : { *(.rela.plt)
/DISCARD/ : { *(.rela.dyn)

and we produced output with this sections. That is not ideal.
The solution this patch suggests is simple: do not ignore synthetic
rel[a] sections. That way we can enable common discarding logic
for them and report a proper error.

Differential revision: https://reviews.llvm.org/D41640

llvm-svn: 328419
2018-03-24 13:10:19 +00:00
George Rimar 54634f1990 [ELF] - Another fix for "LLD crashes with --emit-relocs when trying to proccess .eh_frame"
This fixes PR36367 which is about segfault when --emit-relocs is
used together with .eh_frame sections which happens because
of reordering of regular and .rel[a] sections.

Path changes loop that iterates over input sections to create
relocation target sections first.

Differential revision: https://reviews.llvm.org/D44679

llvm-svn: 328299
2018-03-23 09:18:31 +00:00
George Rimar 84bcabcb86 [ELF] - Show data and assignment commands in the map file.
Patch teaches LLD to print BYTE/SHORT/LONG/QUAD and
location move commands to the map file.

Differential revision: https://reviews.llvm.org/D44004

llvm-svn: 327612
2018-03-15 09:16:40 +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 afbf90aef9 [ELF] - Drop special flags for empty output sections.
This fixes PR36598.

LLD currently crashes when we have empty output section
with SHF_LINK_ORDER flag. This might happen if we place an 
empty synthetic section in the linker script, but keep output
section alive with the use of additional symbol, for example.

The patch fixes the issue by dropping all special flags
for empty sections.

Differential revision: https://reviews.llvm.org/D44376

llvm-svn: 327374
2018-03-13 08:32:56 +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
Rui Ueyama 301305fd3d Use exact uint32_t for uint32_t ELF field. NFC.
llvm-svn: 326934
2018-03-07 19:25:36 +00:00
George Rimar 527bfd7a48 [ELF] - Recommit r326892,r326893 "[ELF] - Report LMA region overflows."
With fix: add missing "RUN:" prefix to test case.

Original commit message:
We do not report LMA region overflows currently.
Both GNU linkers do that. The patch implements it.

Differential revision: https://reviews.llvm.org/D44094

llvm-svn: 326895
2018-03-07 12:44:18 +00:00
George Rimar 06846c2251 [ELF] - Revert r326892, r326893.
Bots are still unhappy:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/26259

llvm-svn: 326894
2018-03-07 12:33:00 +00:00
George Rimar 97e054e00d [ELF] - Report LMA region overflows.
We do not report LMA region overflows currently.
Both GNU linkers do that. The patch implements it.

Differential revision: https://reviews.llvm.org/D44094

llvm-svn: 326892
2018-03-07 11:54:30 +00:00
George Rimar 54baa5f45f [ELF] - Allow discarding .hash and .gnu.hash from linker script.
Currently, LLD segfaults when linker script attempts to discard
one of the hash sections. This patch fixes that.

Differential revision: https://reviews.llvm.org/D44012

llvm-svn: 326891
2018-03-07 11:47:15 +00:00
George Rimar 162d436c8e [ELF] - Support moving location counter when MEMORY is used.
We do not expand memory region correctly for following scripts:

.foo.1 : 
 {
   *(.foo.1)
   . += 0x1000;
 } > ram
Patch generalizes expanding of output sections and memory
regions in one place and fixes the issue.

Differential revision: https://reviews.llvm.org/D43999

llvm-svn: 326688
2018-03-05 10:54:03 +00:00
George Rimar 97785af464 [ELF] - Report error when memory region is overflowed by data commands.
LLD can not catch a memory area overflow when using a data command.
If we have the script below:

.foo : 
{
  *(.foo)
  BYTE(0x1)
} > ram

where BYTE overflows the ram region, we do not report it currently.
Patch fixes that.

Differential revision: https://reviews.llvm.org/D43948

llvm-svn: 326545
2018-03-02 08:11:58 +00:00
Rafael Espindola e75b42ee4e Don't allocate a header bellow address 0.
With the current code if the script has a PHDRS we always obey and try
to allocate a header. This can cause Min - HeaderSize to underflow.

It looks like bfd actually prints an error for this case. With this
patch we do the same.

Found while looking at pr36515.

llvm-svn: 326441
2018-03-01 15:25:46 +00:00
George Rimar c4df670dea [ELF] - Do not remove empty sections that use symbols in expressions.
This is PR36515.

Currenly if we have a script like .debug_info 0 : { *(.debug_info) },
we would not remove this section and keep it in the output.
That does not work, because it is common case for
debug sections to have a zero address expression.
Patch changes behavior so that we remove only sections
that do not use symbols in its expressions.

Differential revision: https://reviews.llvm.org/D43863

llvm-svn: 326430
2018-03-01 12:27:04 +00:00
Rafael Espindola 852bd5c062 Simplify removing empty output sections.
With this the meaning of the Live bit in output sections is clear: we
have at some point added a input section into it.

llvm-svn: 326401
2018-03-01 01:08:00 +00:00