Commit Graph

776 Commits

Author SHA1 Message Date
George Rimar d6bcde389a [ELF] - Fix "--symbol-ordering-file doesn't work with linker scripts"
This is PR33889,

Patch adds support of combination of linkerscript and
-symbol-ordering-file option.

If no sorting commands are present in script inside section declaration
and no --sort-section option specified, code uses sorting from ordering 
file if any exist.

Differential revision: https://reviews.llvm.org/D35843

llvm-svn: 310045
2017-08-04 10:25:29 +00:00
Rafael Espindola a2df2f09f4 Avoid warnings when asserts are disabled.
llvm-svn: 309326
2017-07-27 21:42:42 +00:00
Rafael Espindola 8c022ca783 Merge OutputSectionCommand and OutputSection.
This is a bit of a hack, but it is *so* convenient.

Now that we create synthetic linker scripts when none is provided, we
always have to handle paired OutputSection and OutputsectionCommand and
keep a mapping from one to the other.

This patch simplifies things by merging them and creating what used to
be OutputSectionCommands really early.

llvm-svn: 309311
2017-07-27 19:22:43 +00:00
George Rimar aa3541875e [ELF] - Store PhdrEntry values by pointers instead of storing by value.
That is slightly more convinent as allows to store pointer on
program header entry in a more safe way.
 
Change was used in 2 patches currently on review.

Differential revision: https://reviews.llvm.org/D35832

llvm-svn: 309253
2017-07-27 07:46:50 +00:00
Rui Ueyama 709fb2bb10 Rename ObjectFile -> ObjFile.
Rename it because it was too easy to conflict with llvm::object::ObjectFile
which broke buildbots several times.

llvm-svn: 309199
2017-07-26 22:13:32 +00:00
Rafael Espindola a5e8dd35b0 Simplify. NFC.
llvm-svn: 309153
2017-07-26 18:47:49 +00:00
Rafael Espindola 244ef98161 Detemplate SymbolTable.
NFC, just makes it easier to access from non templated code.

llvm-svn: 309152
2017-07-26 18:42:48 +00:00
George Rimar f694d33f4c [ELF] - Fix calculation of memory region offset.
This is PR33714.

Previously for each input section offset of memory region
was incremented on a size of output section.

That resulted in a wrong error message saying about
overflow. Patch fixes that.

Differential revision: https://reviews.llvm.org/D35803

llvm-svn: 308955
2017-07-25 08:29:29 +00:00
Rafael Espindola ca5740d95a Don't crash on an empty section with an ALIGN.
llvm-svn: 308809
2017-07-22 00:00:51 +00:00
Petr Hosek 8b591f592b [ELF] Remove processNonSectionCommands
This method is no longer being used anywhere.

Differential Revision: https://reviews.llvm.org/D35706

llvm-svn: 308706
2017-07-21 01:02:30 +00:00
George Rimar 67c60727ce [ELF] - Apply clang-format. NFC.
llvm-svn: 308297
2017-07-18 11:55:35 +00:00
Shoaib Meenai e1d7776c53 [ELF] Use stable_sort for compareByFilePosition
The comment at the top of compareByFilePosition indicates that it relies
on stable_sort to preserve the order of synthetic sections. We were
using sort instead of stable_sort, however, leading to incorrect
synthetic section ordering.

Differential Revision: https://reviews.llvm.org/D35473

llvm-svn: 308207
2017-07-17 19:42:19 +00:00
Rui Ueyama 1e77ad1456 Move feature-specific functions out of Strings.cpp.
Functions declared in Strings.h should provide generic string operations
for the linker, but some of them are too specific to some features. This
patch moves them to the location where they are used.

llvm-svn: 307949
2017-07-13 20:30:35 +00:00
George Rimar 8c804d9746 [ELF] - Allow moving location counter backward in some cases.
Patch removes restriction about moving location counter
backwards outside of output sections declarations.

That may be useful for some apps relying on such scripts, 
known example is linux kernel.

Differential revision: https://reviews.llvm.org/D34977

llvm-svn: 307794
2017-07-12 14:50:25 +00:00
Peter Smith c1ace40bf9 [ELF] Add comment to explain LinkerScript::CurAddressState [NFC]
r307367 via D34345 split out the temporary address state used within
processCommands() and assignAddresses(). Due to the way that getSymbolValue
is used by the ScriptParser there is no way of giving the current
OutputSection to getSymbolValue() without somehow accessing the created
addressState. The suggestion was that by making a pointer that would go out
of scope we would find out by ASAN/MSAN or a crash if someone had misused
currentAddressState.

Differential Revision: https://reviews.llvm.org/D34345

llvm-svn: 307637
2017-07-11 09:28:27 +00:00
Peter Smith 906e9a1898 [ELF] Extract temporary state used in assignAddresses()
The assignAddresses() function accumulates state in the LinkerScript that
prevents it from being called multiple times. This change moves the state
into a separate structure AddressState that is created at the start of the
function and disposed of at the end.

CurAddressState is used rather than passing a reference to the state as a
parameter to the functions used by assignAddresses(). This is because the
getSymbolValue function needs to be executed in the context of AddressState
but it is stored in ScriptParser when AddressState is not available.

The AddressState is also used in a limited context by processCommands()

Differential Revision: https://reviews.llvm.org/D34345

llvm-svn: 307367
2017-07-07 09:11:27 +00:00
Rafael Espindola 2126334e08 Move fabricateDefaultCommands earlier.
It is now just after the OutputSections are created, which is as early
as it can possibly go.

llvm-svn: 307225
2017-07-05 23:36:24 +00:00
Rafael Espindola 9f9e99be20 Simplify. NFC.
llvm-svn: 307217
2017-07-05 22:30:04 +00:00
Rafael Espindola cf7347379f Remove a function that is now trivial.
llvm-svn: 307214
2017-07-05 22:25:38 +00:00
Rafael Espindola d7faa9165f Merge createOrphanCommands into addOrphanSections.
This is a bit simpler and avoids a walk over OutputSections.

llvm-svn: 307178
2017-07-05 17:50:43 +00:00
Peter Smith 5aedebff38 [ELF] Extract allocateHeaders() from assignAddresses()
The allocateHeaders() function is called at the end of assignAddresses(), it
decides whether the ELF header and program header table can be allocated to
a PT_LOAD program header. As the function alters state, it prevents
assignAddresses() from being called multiple times.

This change splits out the call to allocateHeaders() from assignAddresses()
this will permit assignAddresses() to be called while processing range
extension thunks without trying to allocateHeaders().

Differential Revision: https://reviews.llvm.org/D34344

llvm-svn: 307131
2017-07-05 09:12:54 +00:00
George Rimar a951d5c40b [ELF] - Use llvm::find_if instead std::find_if where possible. NFC.
Two more places.

llvm-svn: 307076
2017-07-04 13:10:37 +00:00
George Rimar d971e7030e [ELF] - Simplify allocateHeaders(). NFC.
* Return type changed to void, because it was unused.
* std::find_if -> llvm::find_if

llvm-svn: 307039
2017-07-03 16:05:51 +00:00
Andrew Ng a020d3487e [LLD][LinkerScript] Allow non-alloc sections to be assigned to segments.
This patch makes changes to allow sections without the SHF_ALLOC bit to be
assigned to segments in a linker script.

The assignment of output sections to segments is performed in
LinkerScript::createPhdrs. Previously, this function would bail as soon as it
encountered an output section which did not have the SHF_ALLOC bit set, thus
preventing any output section without SHF_ALLOC from being assigned to a
segment.

This restriction has now been removed from LinkerScript::createPhdrs and instead
a check for SHF_ALLOC has been added to LinkerScript::adjustSectionsAfterSorting
to not propagate program headers to sections without SHF_ALLOC which matches the
behaviour of bfd linker scripts.

Differential Revision: https://reviews.llvm.org/D34204

llvm-svn: 307013
2017-07-03 10:11:25 +00:00
Rui Ueyama 82143d3fbb Move `assert` upwards so that it fails early if it fails.
llvm-svn: 306308
2017-06-26 17:11:36 +00:00
Rafael Espindola 9c0395e39e Prefer -Ttext over linker script values.
I found this while trying to build u-boot. It uses -Ttext in
combination with linker scripts.

My first reaction was to change the linker scripts to have the correct
value, but I found that it is actually quite convenient to have -Ttext
take precedence.

By having just

.text : { *(.text) }

In the script, they can define the text address in a single Makefile
and pass it to ld with -Ttext and for the C code with
-DFoo=value. Doing the same with linker scripts would require them to
be generated during the build.

llvm-svn: 305766
2017-06-20 01:51:50 +00:00
Andrew Ng 6e9f98c198 [LLD][LinkerScript] Add support for segment NONE.
This patch adds support for segment NONE in linker scripts which enables the
specification that a section should not be assigned to any segment.

Note that GNU ld does not disallow the definition of a segment named NONE, which
if defined, effectively overrides the behaviour described above. This feature
has been copied.

Differential Revision: https://reviews.llvm.org/D34203

llvm-svn: 305700
2017-06-19 15:28:58 +00:00
Rafael Espindola 4f1fca270a Error when discarding .dynstr.
We would crash before.

llvm-svn: 305615
2017-06-16 23:53:36 +00:00
Rafael Espindola 656cc20f5b Error when discarding .dynsym.
We would crash instead before.

llvm-svn: 305614
2017-06-16 23:50:09 +00:00
Rafael Espindola 2af64b0bf8 Error on trying to discard .dynamic.
We would crash instead before.

llvm-svn: 305613
2017-06-16 23:45:35 +00:00
Rui Ueyama e6d8c1cb38 Update a comment.
llvm-svn: 305601
2017-06-16 22:45:13 +00:00
Rafael Espindola 383971d2a7 Move clearOutputSections before sortSections.
This is probably the main patch left in unifying our intermediary
representation.

It moves the creation of default commands before section sorting. This
has the nice effect that we now have one location where we decide
where an orphan section should be placed.

Before this patch sortSections would decide the relative location of
orphan sections to other sections, but it was up to placeOrphanSection
to decide on the exact location.

We now only sort sections we created since the linker script is
already in the correct order.

llvm-svn: 305512
2017-06-15 21:51:01 +00:00
Rafael Espindola e86fddd651 Simplify. NFC.
llvm-svn: 305341
2017-06-13 23:54:34 +00:00
Rafael Espindola f51c80559c Make OutputSections and OutputSectionCommands globals.
This is similar to what we do for InputSections and makes them easier
to access.

llvm-svn: 305337
2017-06-13 23:26:31 +00:00
Rafael Espindola dece28087e Set non alloc section address to 0 earlier.
Currently we do layout as if non alloc sections had an actual address
and then set it to zero. This produces a few odd results where a
symbol has an address that is inconsistent with the section address.

The simplest way to fix it is probably to just set the address earlier.

The behavior of bfd seems to be similar, but it only sets the non
alloc section address is missing from the linker script or if the
script has an explicit " : 0" setting the address of the output
section (which the default script does).

llvm-svn: 305323
2017-06-13 20:57:43 +00:00
Rafael Espindola 7ff9329b7c Move clearOutputSections before createPhdrs. NFC.
llvm-svn: 305156
2017-06-10 22:12:32 +00:00
Rafael Espindola e76231b647 Move fabricateDefaultCommands earlier.
This then requires delaying a call to getHeaderSize.

llvm-svn: 304961
2017-06-08 04:17:04 +00:00
George Rimar fbb0463f39 [ELF] - Linkerscript: implement NOLOAD section type.
This is PR32351

Each output section may have a type. The type is a keyword in parentheses.
(https://sourceware.org/binutils/docs/ld/Output-Section-Type.html#Output-Section-Type)
This patch support only one type, it is NOLOAD.
If output section has such type, we force it to be SHT_NOBITS. 

More details are available on a review page.

Differential revision: https://reviews.llvm.org/D33647

llvm-svn: 304925
2017-06-07 16:31:08 +00:00
Peter Smith 8e791463ef [ELF] Convert Thunks to use InputSectionDescriptions
Thunks are now generated per InputSectionDescription instead of per
OutputSection. This allows created ThunkSections to be inserted directly
into InputSectionDescription.

Changes in this patch:
- Loop over InputSectionDescriptions to find relocations to Thunks
- Generate a ThunkSection per InputSectionDescription
- Remove synchronize() as we no longer need it
- Move fabricateDefaultCommands() before createThunks

Differential Revision: https://reviews.llvm.org/D33835

llvm-svn: 304887
2017-06-07 09:35:14 +00:00
George Rimar 41c7ab4a3d [ELF] - Linkerscript: improved error reporting.
When linking linux kernel LLD currently reports next errors:

ld: error: unable to evaluate expression: input section .head.text has no output section assigned
ld: error: At least one side of the expression must be absolute
ld: error: At least one side of the expression must be absolute

That does not provide file/line information and overall looks unclear. 
Patch adds location information to ExprValue and that allows
to provide more clear error messages.

Differential revision: https://reviews.llvm.org/D33943

llvm-svn: 304881
2017-06-07 08:54:43 +00:00
Zachary Turner 264b5d9e88 Move Object format code to lib/BinaryFormat.
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.

Differential Revision: https://reviews.llvm.org/D33843

llvm-svn: 304864
2017-06-07 03:48:56 +00:00
Rafael Espindola 658a0c74ec Avoid using OutputSection::Sections. NFC.
We now used the InputSectionDescriptions in
OutputSectionCommand::finalize. This will allow moving
clearOutputSections earlier.

llvm-svn: 304827
2017-06-06 20:13:19 +00:00
Rafael Espindola 8c284acf14 Move finalize to OutputSectionCommands. NFC.
This removes a mapping from OutputSection to OutputSectionCommand and
is another step in moving clearOutputSections earlier.

llvm-svn: 304821
2017-06-06 19:40:01 +00:00
George Rimar 1124001c68 [ELF] - Early return from writeTo() if section is SHT_NOBITS. NFCi.
That addresses port commit comments for https://reviews.llvm.org/D33646

llvm-svn: 304777
2017-06-06 07:46:28 +00:00
Rafael Espindola 0f7dc0e2d0 Run fabricateDefaultCommands before fixSectionAlignments.
This allows us to remove the PageAlign field. It will also allow
moving fabricateDefaultCommands earlier.

llvm-svn: 304513
2017-06-02 01:37:58 +00:00
Rafael Espindola bb7bd3eefe Simplify. NFC.
llvm-svn: 304511
2017-06-02 01:24:37 +00:00
Rafael Espindola 6888072808 Move maybeCompress to OutputSectionCommand.
This removes a call to getCmd and allows us to move
clearOutputSections earlier.

llvm-svn: 304439
2017-06-01 16:57:48 +00:00
Rafael Espindola faf25a7216 Convert a few more uses of OutputSections. NFC.
Also needed to move clearOutputSections earlier.

llvm-svn: 304420
2017-06-01 16:26:28 +00:00
Rafael Espindola 05c4f67cf3 Move name lookup to script parsing time.
We were looking up sections by name during expression evaluation. By
keeping track of forward declarations we can do the lookup during
script parsing.

Doing the lookup earlier will be more efficient when assignAddresses
is run twice and removes two uses of OutputSections.

llvm-svn: 304381
2017-06-01 01:16:50 +00:00
Rafael Espindola 969c6512c2 Move clearOutputSections earlier.
Another step into merging the linker script and non linker script code
paths.

llvm-svn: 304339
2017-05-31 20:22:27 +00:00
Rafael Espindola db5e56f7b2 Store a single Parent pointer for InputSectionBase.
Before InputSectionBase had an OutputSection pointer, but that was not
always valid. For example, if it was a merge section one actually had
to look at MergeSec->OutSec.

This was brittle and caused bugs like the one fixed by r304260.

We now have a single Parent pointer that points to an OutputSection
for InputSection, but to a SyntheticSection for merge sections and
.eh_frame. This makes it impossible to accidentally access an invalid
OutSec.

llvm-svn: 304338
2017-05-31 20:17:44 +00:00
Rafael Espindola d54c566510 Simplify. NFC.
llvm-svn: 304334
2017-05-31 19:53:40 +00:00
Rafael Espindola e39709b20d Check Live instead of the section type.
By the time we get here all live sections should have been combined
into InputSections.

llvm-svn: 304243
2017-05-30 20:40:03 +00:00
Rafael Espindola a85e8dda54 Remove unnecessary cast.
llvm-svn: 304240
2017-05-30 20:24:52 +00:00
George Rimar d4096140e3 [ELF] - Do not crash when linkerscript applies fill to .bss.
I found that during visual inspection of code while wrote different patch.
Script in testcase probably have nothing common with real life, but
we segfault currently using it.

If output section is known NOBITS, there is no need to create
writers threads for doing nothing or proccess any filler logic that 
is useless here. We can just early return, that is what this patch do.

DIfferential revision: https://reviews.llvm.org/D33646

llvm-svn: 304192
2017-05-30 05:48:09 +00:00
Petr Hosek 08dfd53269 [ELF] Filter out non InputSection members from InputSections
InputSections may contain MergeInputSection members which trigger
a segmentation fault when trying to cast them to InputSection.

Differential Revision: https://reviews.llvm.org/D33628

llvm-svn: 304189
2017-05-30 05:17:58 +00:00
Petr Hosek 3c6de1a66c [ELF] Use late evaluation for ALIGN in expression
While the following expression is handled fine:

  PROVIDE_HIDDEN(newsym = oldsym + address);

The following expression triggers an error because the expression
is evaluated as absolute:

  PROVIDE_HIDDEN(newsym = ALIGN(oldsym, CONSTANT(MAXPAGESIZE)) + address);

To avoid this error, we use late evaluation for ALIGN by making the
alignment an attribute of the expression itself.

Differential Revision: https://reviews.llvm.org/D33629

llvm-svn: 304185
2017-05-30 03:18:28 +00:00
Rafael Espindola 55b169bf5d Move writeTo to OutputSectionCommand.
This reduces how many times we have to map from OutputSection to
OutputSectionCommand. It is a required step to moving
clearOutputSections earlier.

In order to always use writeTo in OutputSectionCommand we have to call
fabricateDefaultCommands for -r links and move section compression
after it.

llvm-svn: 303784
2017-05-24 18:08:04 +00:00
Dmitry Mikulin fd0c844fbb Do not track section types of previous sections, always use PROGBITS for dummy sections.
Fix for PR33029.

llvm-svn: 303770
2017-05-24 16:48:31 +00:00
Rafael Espindola 6a1aa8d9b4 Use more strict types. NFC.
By the time we get to linker scripts, all special InputSectionBase
should have been combined into synthetic sections, which are a type of
InputSection. The net result is that we can use InputSection in a few
places that were using InputSectionBase.

llvm-svn: 303702
2017-05-23 22:47:31 +00:00
Rafael Espindola a46f688e8f Use linker script commands in writeMapFile.
This converts the last (chronologically) user of OutputSections to use
the linker script commands instead.

The idea is to convert all uses after fabricateDefaultCommands, so
that we have a single representation.

llvm-svn: 303384
2017-05-18 21:30:14 +00:00
Rafael Espindola d7dc225888 Use a DenseMap in LinkerScript::getCmd.
This improves many-sections.s with a linker script from 22s to 0.9s.

llvm-svn: 302708
2017-05-10 19:13:38 +00:00
Rafael Espindola fa948c724a Refactor OutputSection to OutputSectionCommand mapping.
We now always use getCmd. I will optimize it in a followup commit.

llvm-svn: 302706
2017-05-10 19:00:23 +00:00
Rafael Espindola 3f38e818ac Remove one more use of section names.
llvm-svn: 302672
2017-05-10 14:35:20 +00:00
Rafael Espindola 2c923c2c37 Remove another use of section names. NFC.
llvm-svn: 302671
2017-05-10 14:28:31 +00:00
George Rimar 608cf67084 [ELF] - Don't segfault when assigning non-calculatable absolute symbol value.
This is PR32664.

Issue was revealed by linux kernel script which was:

SECTIONS {
 . = (0xffffffff80000000 + ALIGN(0x1000000, 0x200000));
 phys_startup_64 = ABSOLUTE(startup_64 - 0xffffffff80000000);

 .text : AT(ADDR(.text) - 0xffffffff80000000) {
.....
  *(.head.text)
Where startup_64 is in .head.text.

At the place of assignment to phys_startup_64 we can not calculate absolute value for startup_64
because .text section has no VA assigned. Two patches were prepared earlier to address this: D32173 and D32174.

And in comments for D32173 was suggested not try to support this case, but error out.

Differential revision: https://reviews.llvm.org/D32793

llvm-svn: 302668
2017-05-10 14:23:33 +00:00
Rafael Espindola dc1ed12015 Remove another use of section names. NFC.
llvm-svn: 302662
2017-05-10 14:12:02 +00:00
Rafael Espindola c5b612b8b4 Don't use section names in getFiller. NFC.
This is just faster and avoids using names.

llvm-svn: 302661
2017-05-10 14:01:13 +00:00
George Rimar d86a4e505b [ELF] - Linkerscript: support combination of linkerscript and --compress-debug-sections.
Previously it was impossible to use linkerscript with --compress-debug-sections 
because of assert failture:
Assertion failed: isFinalized(), file C:\llvm\lib\MC\StringTableBuilder.cpp, line 64

Patch fixes the issue

llvm-svn: 302413
2017-05-08 10:18:12 +00:00
Rafael Espindola 660c9ab929 Delete LinkerScript::getSectionIndex.
We can set SectionIndex tentatively as we process the linker script
instead of looking it repeatedly.

In general we should try to have as few name lookups as possible.

llvm-svn: 302299
2017-05-05 21:34:26 +00:00
Rafael Espindola 02ed7575e7 Simplify the header allocation.
In the non linker script case we would try very early to find out if
we could allocate the headers. Failing to do that would add extra
alignment to the first ro section, since we would set PageAlign
thinking it was the first section in the PT_LOAD.

In the linker script case the header allocation must be done in the
end, causing some duplication.

We now tentatively add the headers to the first PT_LOAD and if it
turns out they don't fit, remove them. With this we only need to
allocate the headers in one place in the code.

llvm-svn: 302186
2017-05-04 19:34:17 +00:00
Rafael Espindola 7c4eafa3ee Fix accounting of tbss.
We were correctly computing the size contribution of a .tbss input
section (it is none), but we were incorrectly considering the
alignment of the output section: it was advancing Dot instead of
ThreadBssOffset.

As far as I can tell this was always wrong in our linkerscript
implementation, but that became more visible now that the code is
shared with the non linker script case.

llvm-svn: 302107
2017-05-04 03:00:27 +00:00
Peter Smith c60b4510ea [ELF] Fix problems with fabricateDefaultCommands() and --section-start
The --section-start <name>=<address> needs to be translated into equivalent
linker script commands. There are a couple of problems with the existing
implementation:
- The --section-start with the lowest address is assumed to be at the start
of the map. This assumption is incorrect, we have to iterate through the
SectionStartMap to find the lowest address.
- The addresses in --section-start were being over-aligned when the
sections were marked as PageAlign. This is inconsistent with the use of
SectionStartMap in fixHeaders(), and can cause problems when the PageAlign
causes an "unable to move location counter backward" error when the
--section-start with PageAlign is aligned to an address higher than the next
--section-start. The ld.bfd and ld.gold seem to be more consistent with this
approach but this is not a well specified area.
    
This change fixes the problems above and also corrects a typo in which
fabricateDefaultCommands() is called with the wrong parameter, it should be
called with AllocateHeader not Config->MaxPageSize.

Differential Revision: https://reviews.llvm.org/D32749

llvm-svn: 302007
2017-05-03 08:44:50 +00:00
Rafael Espindola 4aa2ef5b0e Fix pr32816.
When using linkerscripts we were trying to sort SHF_LINK_ORDER
sections too early. Instead of always doing two runs of
assignAddresses, record the section order in processCommands.

llvm-svn: 301830
2017-05-01 20:32:39 +00:00
Rafael Espindola de8d9897d9 Bring back r301678.
This version uses a set to speed up the synchronize method.

Original message:

    Remove LinkerScript::flush.

    This patch replaces flush with a last ditch attempt at synchronizing
    the section list with the linker script "AST".

    The synchronization is a bit of a hack and should in time be avoided
    by creating the AST earlier so that modifications can be made directly
    to it instead of modifying the section list and synchronizing it back.

    This is the main step for fixing
    https://bugs.llvm.org/show_bug.cgi?id=32816. With this in place I
    think the only missing thing would be to have processCommands assign
    section indexes as dummy offsets so that the sort in
    OutputSection::finalize works.

    With this LinkerScript::assignAddresses becomes much simpler, which
    should help with the thunk work.

llvm-svn: 301745
2017-04-29 15:44:03 +00:00
Rui Ueyama 216aa11cc5 Revert r301678: Remove LinkerScript::flush.
This reverts commit r301678 since that change significantly slowed
down the linker. Before this patch, LLD could link clang in 8 seconds,
but with this patch it took 40 seconds.

llvm-svn: 301709
2017-04-28 22:40:58 +00:00
Rafael Espindola a7a945a13b Rename one of the variables to avoid confusion.
llvm-svn: 301691
2017-04-28 21:23:43 +00:00
Rafael Espindola b3bc1ed0d4 Remove LinkerScript::flush.
This patch replaces flush with a last ditch attempt at synchronizing
the section list with the linker script "AST".

The synchronization is a bit of a hack and should in time be avoided
by creating the AST earlier so that modifications can be made directly
to it instead of modifying the section list and synchronizing it back.

This is the main step for fixing
https://bugs.llvm.org/show_bug.cgi?id=32816. With this in place I
think the only missing thing would be to have processCommands assign
section indexes as dummy offsets so that the sort in
OutputSection::finalize works.

With this LinkerScript::assignAddresses becomes much simpler, which
should help with the thunk work.

llvm-svn: 301678
2017-04-28 20:22:47 +00:00
Rafael Espindola 4f013bb3b2 Create an OutputSection for each non-empty OutputSectionCommand.
We were already pretty close, the one exception was when a name was
reused in another SECTIONS directive:

SECTIONS {
  .text : { *(.text) }
  .data : { *(.data) }
}
SECTIONS {
  .data : { *(other) }
}

In this case we would create a single .data and magically output
"other" while looking at the first OutputSectionCommand.

We now create two .data sections. This matches what gold does. If we
really want to create a single one, we should change the parser so that
the above is parsed as if the user had written

SECTIONS {
  .text : { *(.text) }
  .data : { *(.data) *(other)}
}

That is, there should be only one OutputSectionCommand for .data and
it would have two InputSectionDescriptions.

By itself this patch makes the code a bit more complicated, but is an
important step in allowing assignAddresses to operate just on the
linker script.

llvm-svn: 301484
2017-04-26 22:30:15 +00:00
Peter Smith cbfe9e946f [ELF] Always use Script::assignAddresses()
This change fabricates linker script commands for the case where there is
no linker script SECTIONS to control address assignment. This permits us
to have a single Script->assignAddresses() function.
    
There is a small change in user-visible-behavior with respect to the
handling of .tbss SHT_NOBITS, SHF_TLS as the Script->assignAddresses()
requires setDot() to be called with monotically increasing addresses.
The tls-offset.s test has been updated so that the script and non-script
results match.

This change should make the non-script behavior of lld closer to an
equivalent linker script.

Differential Revision: https://reviews.llvm.org/D31888

llvm-svn: 300687
2017-04-19 12:46:32 +00:00
George Rimar 1022112d77 [ELF] - Linkerscript: make section with no content to be SHT_PROGBITS by default.
Imagine next script:

SECTIONS { BYTE(0x11); }

Section content written to disk will be 0x11. Previous LLD behavior was to make this
section SHT_NOBITS. What is not correct because section has content.
ld.bfd makes such sections SHT_PROGBITS, this patch do the same.

This fixes PR32537

Differential revision: https://reviews.llvm.org/D32016

llvm-svn: 300317
2017-04-14 09:37:00 +00:00
George Rimar 01aa795f82 [ELF] LinkerScript: Don't assign zero to all regular symbols
This fixes an assertion `Align != 0u && "Align can't be 0."'
in llvm::alignTo() when a linker script references a globally
defined variable in an ALIGN() context.

Patch by Alexander Richardson !

Differential revision: https://reviews.llvm.org/D31984

llvm-svn: 300315
2017-04-14 09:23:26 +00:00
Rafael Espindola e4c8b9b78c Simplify this further.
Thanks to Rui for noticing it.

llvm-svn: 299777
2017-04-07 16:10:46 +00:00
James Henderson 9d9a663731 [ELF] Recommit r299635 to pad x86 executable sections with 0xcc
This follows r299748 which fixed a latent bug the original commit exposed.

llvm-svn: 299755
2017-04-07 10:36:42 +00:00
Rafael Espindola 7f91d44fba Remove unnecessary cast.
llvm-svn: 299740
2017-04-07 01:25:01 +00:00
Rafael Espindola d1960dc097 Call updateAlignment before assignAddresses.
The alignment expression cannot depend on '.', so we can compute it
early.

llvm-svn: 299717
2017-04-06 21:40:22 +00:00
Rafael Espindola feed750676 Move call to findMemoryRegion before assignAddresses.
This removes a bit more work from assignAddresses.

llvm-svn: 299716
2017-04-06 21:31:24 +00:00
Rafael Espindola 1902b337e9 Remove redundant argument. NFC.
llvm-svn: 299713
2017-04-06 21:26:03 +00:00
Rafael Espindola 9b9800951d Cache the result of findSection.
This avoids calling it multiple times. In particular, we don't have to
call in in assignAddresses any more.

llvm-svn: 299709
2017-04-06 21:05:39 +00:00
James Henderson d983180778 Revert r299635 because it exposed a latent bug.
llvm-svn: 299655
2017-04-06 15:22:58 +00:00
James Henderson 8dd4c06a77 [ELF] Pad x86 executable sections with 0xcc int3 instructions
Executable sections should not be padded with zero by default. On some
architectures, 0x00 is the start of a valid instruction sequence, so can confuse
disassembly between InputSections (and indeed the start of the next InputSection
in some situations). Further, in the case of misjumps into padding, padding may
start to be executed silently.

On x86, the "0xcc" byte represents the int3 trap instruction. It is a single
byte long so can serve well as padding. This change switches x86 (and x86_64) to
use this value for padding in executable sections, if no linker script directive
overrides it. It also puts the behaviour into place making it easy to change the
behaviour of other targets when desired. I do not know the relevant instruction
sequences for trap instructions on other targets however, so somebody should add
this separately.

Because the old behaviour simply wrote padding in the whole section before
overwriting most of it, this change also modifies the padding algorithm to write
padding only where needed. This in turn has caused a small behaviour change with
regards to what values are written via Fill commands in linker scripts, bringing
it into line with ld.bfd. The fill value is now written starting from the end of
the previous block, which means that it always starts from the first byte of the
fill, whereas the old behaviour meant that the padding sometimes started mid-way
through the fill value. See the test changes for more details.

Reviewed by: ruiu

Differential Revision: https://reviews.llvm.org/D30886

Bugzilla: http://bugs.llvm.org/show_bug.cgi?id=32227
llvm-svn: 299635
2017-04-06 09:29:08 +00:00
Rui Ueyama 92a5ba6da5 Remove unnecessary local variable.
This patch does what r299506 was trying to do in a different way.

llvm-svn: 299554
2017-04-05 16:07:44 +00:00
George Rimar 07d7c42c5d Revert r299506 "Simplify. NFC."
It was not NFC unfortunaly,
one of changes decrements begin() iterator and
that is not allowed by MSVS.

llvm-svn: 299525
2017-04-05 09:19:29 +00:00
Rui Ueyama 2ec34544aa Move the parser for the linker script to a separate file.
LinkerScript.cpp contains both the linker script processor and the
linker script parser. I put both into a single file, but the file grown
too large, so it's time to put them into two different files.

llvm-svn: 299515
2017-04-05 05:07:39 +00:00
Rui Ueyama fd9dafdc65 Remove unused typedef.
llvm-svn: 299514
2017-04-05 05:07:18 +00:00
Rui Ueyama 583264e477 Do not use public inheritance where it is not needed.
ScriptParser is not a ScriptLexer, so this should be a private inheritance.

llvm-svn: 299513
2017-04-05 05:06:58 +00:00
Rui Ueyama f62d260744 Simplify. NFC.
llvm-svn: 299512
2017-04-05 05:06:37 +00:00
Rui Ueyama e31d98869d Simplify. NFC.
A for-loop is more boring than a find_if, but I think this is easier to read.

llvm-svn: 299511
2017-04-05 05:06:17 +00:00
Rui Ueyama 01aacc94b9 Fix memory leak found by asan.
llvm-svn: 299509
2017-04-05 03:52:47 +00:00
Rui Ueyama 4e1e88e300 Simplify and update comment.
llvm-svn: 299508
2017-04-05 03:52:28 +00:00
Rui Ueyama c8124ee9a3 Simplify. NFC.
llvm-svn: 299506
2017-04-05 03:21:01 +00:00
Rui Ueyama 8f99f73c8f Use make to create linker script command objects.
It simplifies variable types.

llvm-svn: 299505
2017-04-05 03:20:42 +00:00
Rui Ueyama d379f7357d Remove default arguments because they don't improve readability.
llvm-svn: 299504
2017-04-05 03:20:22 +00:00
Rui Ueyama cba41013ef Add parentheses around `&`.
llvm-svn: 299503
2017-04-05 03:20:03 +00:00
Rui Ueyama d7c5400f9e Update comment.
llvm-svn: 299502
2017-04-05 03:19:43 +00:00
Rui Ueyama cc400cc8ac Use empty() instead of size().
`!V.size()` where V is a vector is equivalent to `V.empty()`.

llvm-svn: 299501
2017-04-05 03:19:24 +00:00
Rui Ueyama 0b2381e71f Simplify. NFC.
llvm-svn: 299500
2017-04-05 03:19:06 +00:00
Rui Ueyama 2e081a4ff0 Make variable names consistent. NFC.
llvm-svn: 299499
2017-04-05 03:18:46 +00:00
Rui Ueyama 72e107f302 Return a result from computeInputSections instead of mutating its argument.
This should improve readability.

llvm-svn: 299498
2017-04-05 02:05:48 +00:00
Rui Ueyama 2c7171bf3c Remove `=` from a lambda that doesn't capture any variable.
llvm-svn: 299495
2017-04-05 00:43:45 +00:00
Rui Ueyama ea93fe00b9 Inline small functions that are used only once as lambdas.
llvm-svn: 299494
2017-04-05 00:43:25 +00:00
Rui Ueyama 5f20b6304b Add newlines.
llvm-svn: 299493
2017-04-05 00:43:05 +00:00
Rui Ueyama a08fa2eca3 Make dummy variable's scope smaller.
llvm-svn: 299492
2017-04-05 00:42:45 +00:00
Rui Ueyama 81cb710784 Update comments.
llvm-svn: 298669
2017-03-24 00:15:57 +00:00
Petr Hosek 30f16b2339 [ELF] Allow references to reserved symbols in linker scripts
This requires collectign all symbols referenced in the linker script
and adding them to symbol table as undefined symbol.

Differential Revision: https://reviews.llvm.org/D31147

llvm-svn: 298577
2017-03-23 03:52:34 +00:00
Rui Ueyama a34da93847 Make elf::ScriptConfig a LinkerScript class member variable.
LinkerScript used to be a template class, so we couldn't instantiate
that class in elf::link. We instantiated ScriptConfig class earlier
instead so that the linker script parser can store configurations to
the object.

Now that LinkerScript is not a template, it doesn't make sense to
separate ScriptConfig from LinkerScript. This patch merges them.

llvm-svn: 298457
2017-03-21 23:03:09 +00:00
Rui Ueyama b8dd23f56e Rename LinkerScriptBase -> LinkerScript.
llvm-svn: 298456
2017-03-21 23:02:51 +00:00
Rui Ueyama fc16173ceb Sort. NFC.
llvm-svn: 298447
2017-03-21 21:49:16 +00:00
Rui Ueyama f93ed4de2e Define Config::Endianness.
This is a shorthand for `Config->IsLE ? support::little : support::big`.

llvm-svn: 298445
2017-03-21 21:40:08 +00:00
Rafael Espindola 195f23c53b Inline a few functions.
I don't foresee having to makes these functions any stricter or
fancier, so it probably makes sense to inline them.

llvm-svn: 298252
2017-03-20 14:35:41 +00:00
Rafael Espindola 49592cf679 Initialize dot.
This would fix an initialized error found by msan. The error is not
showing after r298241, but it is not clear why.

llvm-svn: 298251
2017-03-20 14:33:33 +00:00
George Rimar b17d16a2a1 [ELF] - Reuse Config->IsLE. NFC.
llvm-svn: 298242
2017-03-20 10:16:57 +00:00
George Rimar a8dba48762 [ELF] - Combine LinkerScriptBase and LinkerScript<ELFT>
Patch removes templated linkerscript class.

Unfortunately that required 2 additional static methods
findSymbol() and addRegularSymbol() because code
depends on Symtab<ELFT>::X

Differential revision: https://reviews.llvm.org/D30982

llvm-svn: 298241
2017-03-20 10:09:58 +00:00
George Rimar 009833d377 [ELF] - Apply clang-format. NFC.
llvm-svn: 298240
2017-03-20 09:51:18 +00:00
Rafael Espindola 7ba5f47eb8 Handle & and | of non abs values.
Handling & in particular is probably important because of its use in
aligning addresses.

llvm-svn: 298096
2017-03-17 14:55:36 +00:00
Rafael Espindola 5f08a1dca8 Refuse to add two non absolute symbols.
Since there is no way to produce the correct answer at runtime, it is
probably better to just err.

llvm-svn: 298094
2017-03-17 14:51:07 +00:00
Rafael Espindola f2115f04c8 Support non abs values in the rhs of +.
llvm-svn: 298088
2017-03-17 13:45:36 +00:00
Rafael Espindola 72dc195d78 Change our linker script expr representation.
This fixes pr32031 by representing the expressions results as a
SectionBase and offset. This allows us to use an input section
directly instead of getting lost trying to compute an offset in an
outputsection when not all the information is available yet.

This also creates a struct to represent the *value* of and expression,
allowing the expression itself to be a simple typedef. I think this is
easier to read and will make it easier to extend the expression
computation to handle more complicated cases.

llvm-svn: 298079
2017-03-17 13:05:04 +00:00
Rafael Espindola 490fccb170 Remove unnecessary (). NFC.
llvm-svn: 298076
2017-03-17 13:00:45 +00:00
George Rimar f64618a621 [ELF] - Detemplate SymbolBody::getVA and SymbolBody::getPltVA. NFC.
llvm-svn: 298071
2017-03-17 11:56:54 +00:00
Rui Ueyama 98e55de699 Revert r297850: [ELF] - Linkerscript: make Dot public and remove getDot(). NFC.
This reverts commit r297850 because this change was made
based on a miscommunication.

llvm-svn: 298001
2017-03-16 21:50:30 +00:00
George Rimar 69268a8ab3 [ELF] - Detemplate SymbolBody::getOutputSection(). NFC.
llvm-svn: 297943
2017-03-16 11:06:13 +00:00
George Rimar 20055d4cd2 [ELF] - Linkerscript: make Dot public and remove getDot(). NFC.
Suggested by Rui Ueyama,
also groups member variables in a single place, while I am here.

llvm-svn: 297850
2017-03-15 16:07:02 +00:00
George Rimar 503206c567 [ELF] - Move LinkerScript::discard to LinkerScriptBase. NFC.
Became possible after r297844

llvm-svn: 297848
2017-03-15 15:42:44 +00:00
Petr Hosek 02ad516b2e Support ABSOLUTE on the right hand side in linker scripts
This also requires postponing the assignment the assignment of
symbols defined in input linker scripts since those can refer to
output sections and in case we don't have a SECTIONS command, we
need to wait until all output sections have been created and
assigned addresses.

Differential Revision: https://reviews.llvm.org/D30851

llvm-svn: 297802
2017-03-15 03:33:23 +00:00
George Rimar a2a1ef1abc [ELF] - Move members of LinkerScript to LinkerScriptBase. NFC.
That moves all members that s possible to move for now (all which
does not depend on ELFT templating).

After that change LinkerScript contains only 8 methods in total,
and I believe it is possible to move them all after tweaking other
parts of linker. And we will be able to have single class for 
linkerscript at the end.

llvm-svn: 297735
2017-03-14 12:03:34 +00:00
George Rimar 23e6a02450 [ELF] - Remove unnecessary template #6. NFC.
llvm-svn: 297734
2017-03-14 11:31:28 +00:00
George Rimar f7f0d08827 [ELF] - Remove unnecessary template #5. NFC.
llvm-svn: 297732
2017-03-14 11:23:33 +00:00
George Rimar d83ce1b49d [ELF] - Devirtualize LinkerScriptBase::getOutputSectionSize. NFC.
It does not use ELFT templates so can be non-virtual.

llvm-svn: 297727
2017-03-14 10:24:47 +00:00
George Rimar 851dc1e84d [ELF] - Devirtualize LinkerScriptBase::getOutputSection
It does not use ELFT templates so can be non-virtual.

llvm-svn: 297725
2017-03-14 10:15:53 +00:00
George Rimar 0c1c8085bc [ELF] - Move ThreadBssOffset and Dot to LinkerScriptBase. NFC.
One more step to combine LinkerScript and LinkerScriptBase.

llvm-svn: 297722
2017-03-14 10:00:19 +00:00
George Rimar e21c3af7e9 [ELF] - Remove unnecessary template #4. NFC.
OutputSectionFactory has no ELFT templates anymore.

llvm-svn: 297720
2017-03-14 09:30:25 +00:00
George Rimar 2d2621090d [ELF] - Step to combine LinkerScript and LinkerScriptBase
We can move all not templated functionality to LinkerScriptBase.
Patch do that for hasPhdrsCommands() and shows how it helps to detemplate
things in other places.

Probably we should be able to merge these 2 classes into single one after such steps.
Even if not, it still looks as reasonable cleanup for me.

Differential revision: https://reviews.llvm.org/D30895

llvm-svn: 297714
2017-03-14 09:03:53 +00:00
Eugene Leviant 5784e96f5c [ELF] Fix LMA offset calculation
Differential revision: https://reviews.llvm.org/D30832

llvm-svn: 297713
2017-03-14 08:57:09 +00:00
George Rimar 78aa270041 [ELF] - Remove unnecessary template. NFC.
llvm-svn: 297622
2017-03-13 14:40:58 +00:00
Rafael Espindola 4595df94bb Don't pass Dot to every callback.
It is available from ScriptBase.

llvm-svn: 297472
2017-03-10 16:04:26 +00:00
Rafael Espindola 9bd4566dac Use SectionBase for linker script expressions.
This is a small step for fixing pr32031, which needs expressions that
point to input sections.

llvm-svn: 297431
2017-03-10 00:47:33 +00:00
Rui Ueyama f5fce48679 Handle ":" as a regular token character in linker scripts.
This is an alternative to https://reviews.llvm.org/D30500 to simplify the
version definition parser and allow ":" in symbol names.

Differential Revision: https://reviews.llvm.org/D30722

llvm-svn: 297402
2017-03-09 19:23:00 +00:00
Rafael Espindola 5616adf655 Remove DefinedSynthetic.
With this we have a single section hierarchy. It is a bit less code,
but the main advantage will be in a future patch being able to handle

foo = symbol_in_obj;

in a linker script. Currently that fails since we try to find the
output section of symbol_in_obj.  With this we should be able to just
return an InputSection from the expression.

llvm-svn: 297313
2017-03-08 22:36:28 +00:00
Rafael Espindola 76b6bd355d Remove unnecessary template. NFC.
llvm-svn: 297287
2017-03-08 15:44:30 +00:00
Rafael Espindola 3770763cda Rename Addralign to Alignment.
It now matches the name used in InputSectionBase.

llvm-svn: 297144
2017-03-07 14:55:52 +00:00
Rafael Espindola bedccb5e78 Simplify. NFC.
llvm-svn: 296620
2017-03-01 14:21:31 +00:00
Rafael Espindola bd12e2a0ce Simplify. NFC.
llvm-svn: 296619
2017-03-01 14:12:21 +00:00
Rui Ueyama 80474a26b9 De-template DefinedRegular.
Differential Revision: https://reviews.llvm.org/D30348

llvm-svn: 296508
2017-02-28 19:29:55 +00:00
Rui Ueyama 968db48cee Move SymbolTableSection::getOutputSection to SymbolBody::getOutputSection.
That function doesn't use any member of SymbolTableSection, so I
couldn't see a reason to make it a member of that class. The function
takes a SymbolBody, so it is more natural to make it a member of
SymbolBody.

llvm-svn: 296433
2017-02-28 04:02:42 +00:00
Rui Ueyama 9320cb0719 De-template SyntheticSection.
This class didn't use ELFT.

llvm-svn: 296313
2017-02-27 02:56:02 +00:00
Rui Ueyama 536a26706f Move SymbolTable<ELFT>::Sections out of the class.
The list of all input sections was defined in SymbolTable class for a
historical reason. The list itself is not a template. However, because
SymbolTable class is a template, we needed to pass around ELFT to access
the list. This patch moves the list out of the class so that it doesn't
need ELFT.

llvm-svn: 296309
2017-02-27 02:32:08 +00:00
Rui Ueyama 02a036f2e6 De-template OutputSectionFactory.
Since OutputSection is no longer a template, it doesn't make much
sense to tempalte its factory class.

llvm-svn: 296308
2017-02-27 02:31:48 +00:00
Rui Ueyama 9d1bacb1b4 Remove useless template so that Out<ELFT> becomes just Out.
llvm-svn: 296307
2017-02-27 02:31:26 +00:00
Rafael Espindola 24e6f363c5 Merge OutputSectionBase and OutputSection. NFC.
Now that all special sections are SyntheticSections, we only need one
OutputSection class.

llvm-svn: 296127
2017-02-24 15:07:30 +00:00
Rafael Espindola 29c1afb880 Delete trivial setter.
llvm-svn: 296124
2017-02-24 14:34:12 +00:00
Rafael Espindola 40849419e2 Delete trivial getter.
llvm-svn: 296123
2017-02-24 14:28:00 +00:00
Rafael Espindola 774ea7d0a9 Make InputSection a class. NFC.
With the current design an InputSection is basically anything that
goes directly in a OutputSection. That includes plain input section
but also synthetic sections, so this should probably not be a
template.

llvm-svn: 295993
2017-02-23 16:49:07 +00:00
George Rimar 2146787609 [ELF] - Refactoring of LMA offset handling code. NFC.
Thanks to Rui Ueyama for suggestion.

llvm-svn: 295943
2017-02-23 07:57:55 +00:00
Rafael Espindola c404d50d7c Merge InputSectionData and InputSectionBase.
Now that InputSectionBase is not a template there is no reason to have
the two.

llvm-svn: 295924
2017-02-23 02:32:18 +00:00
Rafael Espindola b4c9b81aad Convert InputSectionBase to a class.
Removing this template is not a big win by itself, but opens the way
for removing more templates.

llvm-svn: 295923
2017-02-23 02:28:28 +00:00
Petr Hosek 5e51f7d24e [ELF] Insert linkerscript symbols directly into symbol table
This change exposes the symbol table insert method and uses it to
insert the linkerscript defined symbols directly into the symbol
table to avoid unnecessarily pulling the object out of an archive.

Differential Revision: https://reviews.llvm.org/D30224

llvm-svn: 295780
2017-02-21 22:32:51 +00:00
George Rimar 78ef645f94 [ELF] - Do not segfault when using --gc-sections with linker script
Patch fixes PR32024.

Sections that were not marked as Live has null output section.
Previously we tried to access that field and segfaulted.

Differential revision: https://reviews.llvm.org/D30188

llvm-svn: 295727
2017-02-21 15:46:43 +00:00
George Rimar ae4761c186 [ELF] - Postpone evaluation of LMA offset.
Previously we evaluated the values of LMA incorrectly for next cases:

.text : AT(ADDR(.text) - 0xffffffff80000000) { ... }
.data : AT(ADDR(.data) - 0xffffffff80000000) { ... }
.init.begin : AT(ADDR(.init.begin) - 0xffffffff80000000) { ... }

Reason was that we evaluated offset when VA was not assigned. For case above
we ended up with 3 loads that has similar LMA and it was incorrect.
That is critical for linux kernel.

Patch updates the offset after VA calculation. That fixes the issue.

Differential revision: https://reviews.llvm.org/D30163

llvm-svn: 295722
2017-02-21 15:08:18 +00:00
George Rimar 2ee2d2dcb5 [ELF] - Improve diagnostic messages for move location counter errors.
Previously LLD would error out just "ld.lld: error: unable to move location counter backward"
What does not really reveal the place of issue,
Patch adds location to the output.

Differential revision: https://reviews.llvm.org/D30187

llvm-svn: 295720
2017-02-21 14:50:38 +00:00
George Rimar 60f1fe8438 [ELF] - Make ASSERT() return Dot instead of evaluated value.
Previously ASSERT we implemented returned expression value.
Ex:
. = ASSERT(0x100);
would set Dot value to 0x100

Form of assert when it is assigned to Dot was implemented for 
compatibility with very old GNU ld which required it.
Some scripts in the wild, including linux kernel scripts 
use such ASSERTs at the end for doing different checks.

Currently we fail with "unable to move location counter backward"
for such scripts. Patch changes ASSERT to return location counter 
value to fix that.

Differential revision: https://reviews.llvm.org/D30171

llvm-svn: 295703
2017-02-21 07:33:38 +00:00
Rafael Espindola 3773bcac55 Fix --print-gc-sections with linker scripts.
Before it would never print anything.

Thanks to George Rimar for pointing it out.

llvm-svn: 295485
2017-02-17 19:37:30 +00:00
George Rimar 647c1685b6 [ELF] - Move DependentSections vector from InputSection to InputSectionBase
I splitted it from D29273.
Since we plan to make relocatable sections as dependent for target ones for
--emit-relocs implementation, this change is required to support .eh_frame case.

EhInputSection inherets from InputSectionBase and not from InputSection.
So for case when it has relocation section, it should be able to access DependentSections
vector.

This case is real for Linux kernel.

Differential revision: https://reviews.llvm.org/D30084

llvm-svn: 295483
2017-02-17 19:34:05 +00:00
Rafael Espindola ecbfd871f9 Don't print DISCARD sections as gced.
This is a small difference I noticed to gold and bfd. When given
--print-gc-sections, we print sections a linkerscript marks
DISCARD. The other linkers don't.

llvm-svn: 295467
2017-02-17 17:35:07 +00:00
Rafael Espindola 679828ff92 Diagnose another case of the location counter moving backwards.
This case should be possible to handle, but it is hard:

* In order to create program headers correctly, we have to scan the
  sections in the order they are in the file.

* To find that order, we have to "execute" the linker script.

* The linker script can contain SIZEOF_HEADERS.

So to support this we have to start with a guess of how many headers
we need (3), run the linker script and try to create the program
headers. If it turns out we need more headers, we run the script again
with a larger SIZEOF_HEADERS.

Also, running the linker script depends on knowing the size of the
sections, so we have to finalize them. But creating the program
headers can change the value stored in some sections, so we have to
split size finalization and content finalization.

Looks like the last part is also needed for range extension thunks, so
we might support this at some point. For now just report an error
instead of producing broken files.

llvm-svn: 295458
2017-02-17 16:26:13 +00:00
Rafael Espindola 4cd7352c4f Reject moving the location counter backwards.
We were only checking when the assignment was inside a section.

llvm-svn: 295454
2017-02-17 16:01:51 +00:00
Rafael Espindola 8290274c13 Share more output section creation code.
We can do this now that the linker script and the writer agree on
which sections should be combined.

llvm-svn: 295341
2017-02-16 17:32:26 +00:00
George Rimar 505ac8dc41 [ELF] - Do not crash when discarding sections that are referenced by others.
SHF_LINK_ORDER sections adds special ordering requirements.
Such sections references other sections. Previously we would crash
if section that other were referenced to was discarded by script.

Patch fixes that by discarding all dependent sections in that case.
It supports chained dependencies, testcase is provided.

Differential revision: https://reviews.llvm.org/D30033

llvm-svn: 295332
2017-02-16 16:06:13 +00:00
Rafael Espindola 908a3d3420 Ignore relocation sections in linker scripts.
Unfortunately, the common way of writing linker scripts seems to be
to get the output of ld.bfd --verbose and edit it a bit.

Also unfortunately, the bfd default script contains things like

.rela.dyn : { *(... .rela.data ...) }

but bfd actually ignores that for -emit-relocs, so we have to do the
same.

llvm-svn: 295324
2017-02-16 14:36:09 +00:00
Rui Ueyama 731a66ae98 Apply different tokenization rules to linker script expressions.
The linker script lexer is context-sensitive. In the regular context,
arithmetic operator characters are regular characters, but in the
expression context, they are independent tokens. This afects how the
lexer tokenizes "3*4", for example. (This kind of expression is real;
the Linux kernel uses it.)

This patch defines function `maybeSplitExpr`. This function splits the
current token into multiple expression tokens if the lexer is in the
expression context.

Differential Revision: https://reviews.llvm.org/D29963

llvm-svn: 295225
2017-02-15 19:58:17 +00:00
Rui Ueyama 794366a237 Rename ScriptParser.{cpp,h} -> ScriptLexer.{cpp,h}.
These files contain a lexer, so the new names are better.
The parser is in LinkerScript.{cpp,h}.

llvm-svn: 295022
2017-02-14 04:47:05 +00:00
Peter Collingbourne 904c5ed558 ELF: Read all dynamic lists specified on the command line.
We were previously only reading the last one.

Fixes PR31939 (which was likely the issue underlying
https://github.com/google/oss-fuzz/issues/295).

Differential Revision: https://reviews.llvm.org/D29861

llvm-svn: 294977
2017-02-13 18:31:12 +00:00
Rafael Espindola ea590d91a0 Revert "Simplify symbol computation for non alloc sections."
This reverts commit r294346. Looks like it regressed the build of
magenta.

llvm-svn: 294460
2017-02-08 15:19:03 +00:00
George Rimar 4e01c3e8cd [ELF] - Linkerscript - fix handling of OUTPUT_ARCH command.
OUTPUT_ARCH command can contain architecture values separated with ":", like:
OUTPUT_ARCH(i386:x86-64)

We did not support that, because got 3 lexer tokens here after recent changes.

This trivial patch fixes the issue, now whole expression inside 
OUTPUT_ARCH is just ignored.

Differential revision: https://reviews.llvm.org/D29640

llvm-svn: 294432
2017-02-08 09:59:06 +00:00
Petr Hosek 165088aa5c [ELF] Handle output section alignment in linker scripts
LLD already parses ALIGN expression to specifiy alignment for output
sections in linker scripts but it never applies the alignment to the
output section. This change handles that.

Differential Revision: https://reviews.llvm.org/D29689

llvm-svn: 294374
2017-02-07 23:42:31 +00:00
Rafael Espindola 193b158b39 Simplify symbol computation for non alloc sections.
We now just keep the address the section would have if it was
allocatable. Only the writer ignores it at the very end.

llvm-svn: 294346
2017-02-07 20:22:04 +00:00
Dmitry Mikulin f3965c0246 Handle the case where 'local' is the name of a global in a version script:
{ global : local; local: *; };

llvm-svn: 294343
2017-02-07 19:50:47 +00:00
George Rimar c6cf1f1f02 [ELF] - Assign proper values for DefinedSynthetic symbols attached to non-allocatable sections.
DefinedSynthetic symbols are attached to sections,
for the case when such symbol was attached to non-allocated section,
we calculated its value incorrectly.

We subtracted Body->Section->Addr, but non-allocatable sections
should have zero VA in output and therefore result value was wrong.

And at the same time we have Body->Section->Addr != 0 for them 
internally because  use it for calculation of section size.

Patch fixes calculation of such symbols values.

Differential revision: https://reviews.llvm.org/D29653

llvm-svn: 294322
2017-02-07 17:51:35 +00:00
George Rimar b2b70975e0 [ELF] - Refactoring: reuse similar method.
We had assignSymbol and assignSectionSymbol methods which has similar functionality.
Patch removes one of copy and reuses another in code.

Differential revision: https://reviews.llvm.org/D29582

llvm-svn: 294290
2017-02-07 10:23:28 +00:00
Rafael Espindola 06f4743a48 Handle symbol assignments before the first section switch.
We now create a dummy section with index 1 before processing the
linker script.

Thanks to George Rimar for finding the bug and providing the initial
testcase.

llvm-svn: 294252
2017-02-06 22:21:46 +00:00
Rafael Espindola 2b07455315 Simplify. NFC.
Now that each OutputSectionCommand maps to just one OutputSection, we
can remove a few std::vectors.

llvm-svn: 294060
2017-02-03 22:27:05 +00:00
Rafael Espindola 4524268c02 Handle numbers followed by ":" in linker scripts.
This is a fix for Bugzilla 31813.

The problem is that the tokenizer does not create a separate token for
":" unless there's white space before it. Changed it to always create
a token for ":" and reworked some logic that relied on ":" being
attached to some tokens like "global:" and "local:".

llvm-svn: 294006
2017-02-03 13:24:01 +00:00
Rui Ueyama 6697ec293c Update comments.
llvm-svn: 293963
2017-02-02 23:26:12 +00:00
George Rimar 697507556a [ELF] - Recommit r293749. Improve comment. NFC.
llvm-svn: 293751
2017-02-01 09:14:22 +00:00
George Rimar 091f9b35c7 [ELF] - Revert r293749
Accidentally lost the commit title and message,
will recommit.

llvm-svn: 293750
2017-02-01 09:12:29 +00:00
George Rimar f46e54f078 (no commit message)
llvm-svn: 293749
2017-02-01 09:05:45 +00:00
George Rimar cc4d3e5745 [ELF] - Linkerscript: properly mark minus expression with non-absolute flag
This is alternative to D28857 which was incorrect.

One of linux scripts contains:

vvar_start = . - 2 * (1 << 12);
vvar_page = vvar_start;
vvar_vsyscall_gtod_data = vvar_page + 128;
Previously we did not mark first expression as non-absolute,
though it contains location counter.

And LLD failed with error:
relocation R_X86_64_PC32 cannot refer to absolute symbol

This patch should fix the issue, and opens road for doing the same for other operators
(though not clear if that is needed).

Differential revision: https://reviews.llvm.org/D29332

llvm-svn: 293748
2017-02-01 09:01:16 +00:00
George Rimar 2fe079233b [ELF] - Linkerscript: do not fail on additional semicolons in linkerscript.
Linux kernel linkerscript contains additional semicolon (last line):

.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
  __apicdrivers = .;
  *(.apicdrivers);

I checked that both gold and bfd are able to parse something like:

.text : { ;;*(.text);;S = 0;; } }

Patch do the same.

Differential revision: https://reviews.llvm.org/D29276

llvm-svn: 293612
2017-01-31 08:50:11 +00:00
Rafael Espindola fe12450e8e Revert commits r293276 and r293278.
[ELF] Fixed formatting. NFC

and

    [ELF] Bypass section type check

    Differential revision: https://reviews.llvm.org/D28761

They do the opposite of what was asked for in the code review.

llvm-svn: 293320
2017-01-27 18:39:30 +00:00
Eugene Leviant 8b7cadcf96 [ELF] Bypass section type check
Differential revision: https://reviews.llvm.org/D28761

llvm-svn: 293276
2017-01-27 11:01:43 +00:00