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

Previously we would merge relocation sections by name.
That did not work in some cases, like testcase shows.

Patch implements logic to merge relocation sections if their target
sections were merged into the same output section.

Differential revision: https://reviews.llvm.org/D33824

llvm-svn: 304886

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

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

This now just requires not calling assignOffsets after it.

llvm-svn: 304861

Before this patch in -r we compute the OutputSection sizes early in
the various calls to assignOffsets. With this change we can remove
most of those calls.

llvm-svn: 304860

We now used the InputSectionDescriptions in
OutputSectionCommand::finalize. This will allow moving
clearOutputSections earlier.

llvm-svn: 304827

This removes a mapping from OutputSection to OutputSectionCommand and
is another step in moving clearOutputSections earlier.

llvm-svn: 304821

llvm-svn: 304820

This is defined by both bfd and gold and used by the android libc.

llvm-svn: 304803

In preparation for inserting Thunks into InputSectionDescription::Sections
extract the loop that finds InputSections that may have calls that need
Thunks. This isn't much benefit now but this will be useful when we have to
extract the InputSectionDescriptions::Sections from the script.

Differential Revision: https://reviews.llvm.org/D33834

llvm-svn: 304783

In preparation for inserting Thunks into InputSectionDescriptions this
simple change associates added Thunks with a vector of InputSections instead
of an OutputSection. As of now we are just using OutputSection::Sections.

Differential Revision: https://reviews.llvm.org/D33832

llvm-svn: 304782

That addresses port commit comments for https://reviews.llvm.org/D33646

llvm-svn: 304777

Previously LLD would fail for case when there are multiple comdats and -r.

That happened because it merged all ".group" (SHT_GROUP) sections into single
output, producing broken result. Such sections may have similar name, alignment and flags
and other properties. We need to produce separate output section for each such input one.

Differential revision: https://reviews.llvm.org/D33643

llvm-svn: 304769

This moves clearOutputSections and OutputSectionCommands creation as
early as possible without changing other code.

llvm-svn: 304751

Traditionally, it has been defined in crtbegin.o, which is typically
provided by libgcc or as part of the C library on some systems. However,
but there's no principled reason for it to be there. We optionaly
define this symbol, which can be used on platforms that don't provide
__dso_handle in crtbegin.o or which don't use crtbegin.o at all.

Differential Revision: https://reviews.llvm.org/D33856

llvm-svn: 304732

procedural optimizations to prevent dropping symbols and allow the linker
to process re-directs.

PR33145: --wrap doesn't work with lto.
Differential Revision: https://reviews.llvm.org/D33621

llvm-svn: 304719

This is PR33289.

Previously LLD leaved section naming as is and that lead to wrong result,
because we decompress sections when using -r,
and hence should remove ".z" prefix.

Differential revision: https://reviews.llvm.org/D33885

llvm-svn: 304711

    
This change alters the sorting for OutputSections with the SHF_LINK_ORDER
flag in OutputSection::finalize() to use the InputSectionDescription
representation and not the OutputSection::Sections representation.

Differential revision: https://reviews.llvm.org/D33772

llvm-svn: 304700

This allows moving clearOutputSections a bit earlier.

llvm-svn: 304654

Spec says: (http://www.sco.com/developers/gabi/latest/ch4.sheader.html)

sh_info
This member holds extra information, whose interpretation depends on the section type.
If the sh_flags field for this section header includes the attribute SHF_INFO_LINK, 
then this member represents a section header table index.

SHF_INFO_LINK
The sh_info field of this section header holds a section header table index.

Since sh_info for SHT_REL[A] sections should contain the section header index of the
section to which the relocation applies, this is
consistent with spec to put this flag. Behavior matches both bfd and gold as well.

Differential revision: https://reviews.llvm.org/D33763

llvm-svn: 304531

This allows us to remove the PageAlign field. It will also allow
moving fabricateDefaultCommands earlier.

llvm-svn: 304513

llvm-svn: 304511

This removes a call to getCmd and allows us to move
clearOutputSections earlier.

llvm-svn: 304439

This is probably the correct location for it: next to
fabricateDefaultCommands. If we don't have a linker script, we
fabricate one. If we have one, we patch it.

llvm-svn: 304436

Now it is as early as it can go: just before synchronize. We now have
to move synchronize earlier too.

llvm-svn: 304434

I don't have a testcase in mind, but there is no reason to have the
linker script out of sync during a -r link.

llvm-svn: 304433

Also needed to move clearOutputSections earlier.

llvm-svn: 304420

This is needed to move clearOutputSections earlier.

llvm-svn: 304419

This is PR33243. R_GOTONLY_PC_FROM_END was not in a list of link time constant
expressions and that was a result of confusiing messages like PR shows:

/usr/bin/ld.lld: error: /usr/lib/go/src/runtime/alg.go:47: 
can't create dynamic relocation R_386_GOTPC against local symbol in readonly segment defined in /tmp/nice/go-link-597453838/go.o

Though in reality we just should not have try to create a dynamic relocation for this case at all.

Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D33717

llvm-svn: 304393

This is PR33239, previously we segfault on given testcase.

Differential revision: https://reviews.llvm.org/D33713

llvm-svn: 304392

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

The sections are ordered, so we can just use the first one when
looking for the lowest address.

llvm-svn: 304369

llvm-svn: 304368

Another step into merging the linker script and non linker script code
paths.

llvm-svn: 304339

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

llvm-svn: 304334

llvm-svn: 304330

llvm-svn: 304328

We would crash if a SHF_LINK_ORDER section pointed to a non
InputSection section. Since those sections are not merged in order,
SHF_LINK_ORDER is pretty meaningless and we can error on that case.

llvm-svn: 304327