Original patch of Shankar Easwaran with additional test case.
The yaml2obj does not allow to create an object file with non-unique
sections names so the fix uses a binary input object file in the test
case.
llvm-svn: 238115
I noticed that gold mark these as hidden. While at it I rewrote the test for
this feature to use yaml rather than an object file as input.
Differential Revision: http://reviews.llvm.org/D9418
Reviewed by: ruiu
llvm-svn: 236291
This patch allow the ARM relocation R_ARM_V4BX to be processed by lld,
although it is not really handled in the static relocation code. The
relocation is in the form:
Relocation section '.rel.text' at offset 0x428 contains 4 entries:
Offset Info Type Sym.Value Sym. Name
00000014 00000028 R_ARM_V4BX
Meaning it does have a direct target, but rather references to an absolute
section *ABS* (in this exemple to the .text segment itself). It makes the
target Atom after file parse to not have a associated pointer and thus
generating a derrefence NULL point in ELFFile<ELFT>::findAtom. Current
approach is just ignore and return nullptr in such cases.
The problem relies that default GCC configuration
for arm-linux-gnueabi{hf} emits the relocation for the asm:
--
.syntax unified
.arm
.p2align 2
.type fn, %function
fn:
ldr r3, .LGOT
ldr r2, .LGOT+4
.LPIC:
add r3, pc, r3
ldr r2, [r3, r2]
cmp r2, #0
bxeq lr
b __start__
.LGOT:
.word _GLOBAL_OFFSET_TABLE_-(.LPIC+8)
.word __start__(GOT)
--
But only with the option -march=armv4 (which is the default GCC configuration).
For arm5 and forward the relocation is not created. This a special relocation
(defined miscellaneous for ARM) that instruct the linker to replace the bx
instruction into a mov. GNU linker has some options related to which substitution
it can create for such cases.
With this patch I can dynamically link an application against a GLIBC
arm-linux-gnueabi system configured with default GCC.
llvm-svn: 235880
Previously, ELFReader takes three template arguments: EFLT,
LinkingContextT and FileT. FileT is itself templated.
So it was a bit complicated. Maybe too much.
Most architectures don't actually need to be parameterized for ELFT.
For example, x86 is always ELF32LE and x86-64 is ELF64LE.
However, because ELFReader requires a ELFT argument, we needed
to parameterize a class even if not needed.
This patch removes the parameter from the class. So now we can
de-templatize such classes (I didn't do that in this patch, though).
This patch also removes ContextT parameter since it didn't have to be
passed as a template argument.
llvm-svn: 234853
DynamicFile and ELFFile are instantiated for four different types,
ELF{32,64}{BE,LE}. Because the classes are instantiated in each
compilation unit, including the header file makes object files
10MB larger.
On Windows, issue of excessive template instantiation is critical,
since the regular COFF file supports only up to 65534 sections.
(We could use the extended COFF file format, but generating that
much COMDAT sections is not a good thing in the first place
because it means long compile time and long link time.)
I confirmed that this change makes AArch64TargetHandler.cpp.o
from 21MB to 8.5MB. It feels still too large, but I think it's
a good start.
llvm-svn: 234808
Simon Atanasyan