Thanks to Andrew Ng for noticing it.

llvm-svn: 303354

This change adds support for the R_ARM_SBREL32 relocation. The relocation
is a base relative relocation that is produced by clang/llvm when -frwpi
is used. The use case for the -frwpi option is position independent data
for embedded systems that do not have a GOT. With -frwpi all data is
accessed via an offset from a base register (usually r9), where r9 is set
at run time to where the data has been loaded. The base of the data is
known as the static base.

The ARM ABI defines the static base as:
B(S) is the addressing origin of the output segment defining the symbol S.
The origin is not required to be the base address of the segment. For
simplicity we choose to use the base address of the segment.

The ARM procedure call standard only defines a read write variant using
R_ARM_SBREL32 relocations. The read-only data is accessed via pc-relative
offsets from the code, this is implemented in clang as -fropi.

Fixes PR32924

Differential Revision: https://reviews.llvm.org/D33280

llvm-svn: 303337

Nothing special here, just detemplates code that became possible 
to detemplate after recent commits in a straghtforward way.

Differential revision: https://reviews.llvm.org/D33234

llvm-svn: 303237

llvm-svn: 303164

llvm-svn: 303155

Follow up for r303150.

llvm-svn: 303153

SymbolTableBaseSection was introduced.

Detemplation of SymbolTableSection should allow to detemplate more things.

Differential revision: https://reviews.llvm.org/D33124

llvm-svn: 303150

Switch to llvm::to_integer() everywhere in LLD instead of 
StringRef::getAsInteger() because API of latter is confusing. 
It returns true on error and false otherwise what makes reading 
the code incomfortable.

Differential revision: https://reviews.llvm.org/D33187

llvm-svn: 303149

We should only ever expect this function to return a regular
InputSection; I would not expect a function definition to be in a
MergeInputSection or EhInputSection. We were previously crashing
in writeTo if this function returned a section that was not an
InputSection because we do not set OutSec for such sections.

This can happen in practice if a function is defined in an empty
section which shares its offset-in-file with a MergeInputSection,
as in the provided test case.

A better fix for this bug would be to fix the
DWARFUnit::collectAddressRanges() interface to provide section
information (see D33183), but this at least fixes the crash.

Differential Revision: https://reviews.llvm.org/D33176

llvm-svn: 303089

Fixes PR33032.

Differential Revision: https://reviews.llvm.org/D33175

llvm-svn: 303088

llvm-svn: 302921

We used to place orphans by just using compareSectionsNonScript.

Then we noticed that since linker scripts can use another order, we
should first try match the section to a given PT_LOAD. But there is
nothing special about PT_LOAD. The same issue can show up for
PT_GNU_RELRO for example.

In general, we have to search for the most similar section and put the
orphan next to it. Most similar being defined as how long they follow
the same code path in compareSecitonsNonScript.

That is what this patch does. We now compute a rank for each output
section, with a bit for each branch in what was
compareSectionsNonScript.

With this findOrphanPos is now fully general and orphan placement can
be optimized by placing every section with the same rank at once.

The included testcase is a variation of many-sections.s that uses
allocatable sections to avoid the fast path in the existing
code. Without threads it goes form 46 seconds to 0.9 seconds.

llvm-svn: 302903

This reverts changes introduced in r302414 "[ELF] - Set DF_STATIC_TLS flag for i386 target."

Because DF_STATIC_TLS does not look to be used by glibc or anything else.

llvm-svn: 302884

Both gold and bfd restrict that one:

ld.bfd: test.o: relocation R_X86_64_TPOFF32 against `var' can not be 
used when making a shared object; recompile with -fPIC
ld.gold: error: test.o: unsupported reloc 23 against global symbol var

What looks reasonable because it is 32 bit one. Patch do the same.

Differential revision: https://reviews.llvm.org/D33100

llvm-svn: 302881

llvm-svn: 302849

llvm-svn: 302848

llvm-svn: 302847

llvm-svn: 302846

This is a bit hackish, but allows for a lot of followup cleanups.

llvm-svn: 302845

llvm-svn: 302843

llvm-svn: 302832

llvm-svn: 302828

llvm-svn: 302826

Differential Revision: https://reviews.llvm.org/D33024

llvm-svn: 302748

llvm-svn: 302719

So that it is clear that the function is a wrapper for for_each_n.

llvm-svn: 302718

This improves many-sections.s with a linker script from 22s to 0.9s.

llvm-svn: 302708

We now always use getCmd. I will optimize it in a followup commit.

llvm-svn: 302706

Previously we were not printing out the type of the incompatible section
which made it difficult to determine what the problem was.

The error message format has been change to the following:

  error: section type mismatch for .shstrtab
  >>> <internal>:(.shstrtab): SHT_STRTAB
  >>> output section .shstrtab: Unknown

Patch by Alexander Richardson.

Differential Revision: https://reviews.llvm.org/D32488

llvm-svn: 302694

This behavior differs from the semantics implemented by GNU linkers
which only define this symbol iff ELF headers are in the memory
mapped segment.

Differential Revision: https://reviews.llvm.org/D33019

llvm-svn: 302687

We used to inherit from it, but don't need it anymore.

llvm-svn: 302675

llvm-svn: 302672

llvm-svn: 302671

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

When compiling LLD using GCC 7 it reports warnings like:
"warning: this statement may fall through [-Wimplicit-fallthrough=]"

LLVM has LLVM_FALLTHROUGH macro which can be used to avoid such warnings.
Together with D33036 this patch fixes them.

Differential revision: https://reviews.llvm.org/D32907

llvm-svn: 302666

llvm-svn: 302662

This is just faster and avoids using names.

llvm-svn: 302661

Differential Revision: https://reviews.llvm.org/D33016

llvm-svn: 302613

Adds support for the ORIGIN and LENGTH linker script built in functions.

  ORIGIN(memory) Return the origin of the memory region
  LENGTH(memory) Return the length of the memory region

Redo of D29775 for refactored linker script parsing.

Patch by Robert Clarke

Differential Revision: https://reviews.llvm.org/D32934

llvm-svn: 302564

This is a bit easier to read and a lot faster in some cases. A version
of many-sections.s with linker scripts goes from 0m41.232s to
0m19.575s.

llvm-svn: 302528