Commit Graph

614 Commits

Author SHA1 Message Date
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