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llvm-project/lld/test/ELF/mips-tls-static.s

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[ELF][MIPS] Do not create a hidden definition for __tls_get_addr on MIPS On most architectures the linker is required to optimize away any references to __tls_get_addr in case of static linking. As usual a special case is MIPS - libc defines __tls_get_addr itself because there are no TLS optimizations for this architecture. llvm-svn: 280664
2016-09-05 23:42:29 +08:00
# Check handling TLS related relocations and symbols when linking
# a static executable.
# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux %s -o %t
# RUN: ld.lld -static %t -o %t.exe
[ELF][MIPS] Support R_MIPS_TLS_DTPREL32 / R_MIPS_TLS_TPREL32 relocations calculation llvm-svn: 280665
2016-09-05 23:42:39 +08:00
# RUN: llvm-objdump -s -t %t.exe | FileCheck %s
[ELF][MIPS] Do not create a hidden definition for __tls_get_addr on MIPS On most architectures the linker is required to optimize away any references to __tls_get_addr in case of static linking. As usual a special case is MIPS - libc defines __tls_get_addr itself because there are no TLS optimizations for this architecture. llvm-svn: 280664
2016-09-05 23:42:29 +08:00
# REQUIRES: mips
[ELF][MIPS] Support R_MIPS_TLS_DTPREL32 / R_MIPS_TLS_TPREL32 relocations calculation llvm-svn: 280665
2016-09-05 23:42:39 +08:00
# CHECK: Contents of section .data:
ELF: Place relro sections after non-relro sections in r/w segment. This is in preparation for my next change, which will introduce a relro nobits section. That requires that relro sections appear at the end of the progbits part of the r/w segment so that the relro nobits section can appear contiguously. Because of the amount of churn required in the test suite, I'm making this change separately. llvm-svn: 291523
2017-01-10 09:21:30 +08:00
# CHECK-NEXT: 30000 0002000c ffff8004 ffff9004
# CHECK: Contents of section .got:
[ELF][MIPS] Multi-GOT implementation Almost all entries inside MIPS GOT are referenced by signed 16-bit index. Zero entry lies approximately in the middle of the GOT. So the total number of GOT entries cannot exceed ~16384 for 32-bit architecture and ~8192 for 64-bit architecture. This limitation makes impossible to link rather large application like for example LLVM+Clang. There are two workaround for this problem. The first one is using the -mxgot compiler's flag. It enables using a 32-bit index to access GOT entries. But each access requires two assembly instructions two load GOT entry index to a register. Another workaround is multi-GOT. This patch implements it. Here is a brief description of multi-GOT for detailed one see the following link https://dmz-portal.mips.com/wiki/MIPS_Multi_GOT. If the sum of local, global and tls entries is less than 64K only single got is enough. Otherwise, multi-got is created. Series of primary and multiple secondary GOTs have the following layout: ``` - Primary GOT Header Local entries Global entries Relocation only entries TLS entries - Secondary GOT Local entries Global entries TLS entries ... ``` All GOT entries required by relocations from a single input file entirely belong to either primary or one of secondary GOTs. To reference GOT entries each GOT has its own _gp value points to the "middle" of the GOT. In the code this value loaded to the register which is used for GOT access. MIPS 32 function's prologue: ``` lui v0,0x0 0: R_MIPS_HI16 _gp_disp addiu v0,v0,0 4: R_MIPS_LO16 _gp_disp ``` MIPS 64 function's prologue: ``` lui at,0x0 14: R_MIPS_GPREL16 main ``` Dynamic linker does not know anything about secondary GOTs and cannot use a regular MIPS mechanism for GOT entries initialization. So we have to use an approach accepted by other architectures and create dynamic relocations R_MIPS_REL32 to initialize global entries (and local in case of PIC code) in secondary GOTs. But ironically MIPS dynamic linker requires GOT entries and correspondingly ordered dynamic symbol table entries to deal with dynamic relocations. To handle this problem relocation-only section in the primary GOT contains entries for all symbols referenced in global parts of secondary GOTs. Although the sum of local and normal global entries of the primary got should be less than 64K, the size of the primary got (including relocation-only entries can be greater than 64K, because parts of the primary got that overflow the 64K limit are used only by the dynamic linker at dynamic link-time and not by 16-bit gp-relative addressing at run-time. The patch affects common LLD code in the following places: - Added new hidden -mips-got-size flag. This flag required to set low maximum size of a single GOT to be able to test the implementation using small test cases. - Added InputFile argument to the getRelocTargetVA function. The same symbol referenced by GOT relocation from different input file might be allocated in different GOT. So result of relocation depends on the file. - Added new ctor to the DynamicReloc class. This constructor records settings of dynamic relocation which used to adjust address of 64kb page lies inside a specific output section. With the patch LLD is able to link all LLVM+Clang+LLD applications and libraries for MIPS 32/64 targets. Differential revision: https://reviews.llvm.org/D31528 llvm-svn: 334390
2018-06-11 15:24:31 +08:00
# CHECK-NEXT: 30010 00000000 80000000 ffff9000 00000001
# CHECK-NEXT: 30020 ffff8000 00000001 00000000
[ELF][MIPS] Support R_MIPS_TLS_DTPREL32 / R_MIPS_TLS_TPREL32 relocations calculation llvm-svn: 280665
2016-09-05 23:42:39 +08:00
#
# CHECK: SYMBOL TABLE:
[ELF][MIPS] Fix initialization of TLS-related GOT entries This patch allows static linking of TLS code. To do that it fixes GOT entries initialization. If TLS-related GOT entry created for a preemptible symbol i.e. has a corresponding dynamic relocation, leave the entry initialized by zero. Write down adjusted TLS symbol's values otherwise. For the adjustments calculation use offsets for thread-local storage. https://www.linux-mips.org/wiki/NPTL llvm-svn: 280914
2016-09-08 17:07:19 +08:00
# CHECK: 0002000c .text 00000000 __tls_get_addr
[ELF][MIPS] Support R_MIPS_TLS_DTPREL32 / R_MIPS_TLS_TPREL32 relocations calculation llvm-svn: 280665
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# CHECK: 00000000 g .tdata 00000000 tls1
[ELF][MIPS] Do not create a hidden definition for __tls_get_addr on MIPS On most architectures the linker is required to optimize away any references to __tls_get_addr in case of static linking. As usual a special case is MIPS - libc defines __tls_get_addr itself because there are no TLS optimizations for this architecture. llvm-svn: 280664
2016-09-05 23:42:29 +08:00
.text
.global __start
__start:
[ELF][MIPS] Fix initialization of TLS-related GOT entries This patch allows static linking of TLS code. To do that it fixes GOT entries initialization. If TLS-related GOT entry created for a preemptible symbol i.e. has a corresponding dynamic relocation, leave the entry initialized by zero. Write down adjusted TLS symbol's values otherwise. For the adjustments calculation use offsets for thread-local storage. https://www.linux-mips.org/wiki/NPTL llvm-svn: 280914
2016-09-08 17:07:19 +08:00
addiu $2, $3, %tlsgd(tls1) # R_MIPS_TLS_GD
addiu $2, $3, %tlsldm(tls2) # R_MIPS_TLS_LDM
addiu $2, $3, %gottprel(tls1) # R_MIPS_TLS_GOTTPREL
[ELF][MIPS] Do not create a hidden definition for __tls_get_addr on MIPS On most architectures the linker is required to optimize away any references to __tls_get_addr in case of static linking. As usual a special case is MIPS - libc defines __tls_get_addr itself because there are no TLS optimizations for this architecture. llvm-svn: 280664
2016-09-05 23:42:29 +08:00
.global __tls_get_addr
__tls_get_addr:
nop
.data
loc:
.word __tls_get_addr
[ELF][MIPS] Support R_MIPS_TLS_DTPREL32 / R_MIPS_TLS_TPREL32 relocations calculation llvm-svn: 280665
2016-09-05 23:42:39 +08:00
.dtprelword tls1+4 # R_MIPS_TLS_DTPREL32
.tprelword tls1+4 # R_MIPS_TLS_TPREL32
.section .tdata,"awT",%progbits
.global tls1
tls1:
.word __tls_get_addr
[ELF][MIPS] Fix initialization of TLS-related GOT entries This patch allows static linking of TLS code. To do that it fixes GOT entries initialization. If TLS-related GOT entry created for a preemptible symbol i.e. has a corresponding dynamic relocation, leave the entry initialized by zero. Write down adjusted TLS symbol's values otherwise. For the adjustments calculation use offsets for thread-local storage. https://www.linux-mips.org/wiki/NPTL llvm-svn: 280914
2016-09-08 17:07:19 +08:00
tls2:
[ELF][MIPS] Support R_MIPS_TLS_DTPREL32 / R_MIPS_TLS_TPREL32 relocations calculation llvm-svn: 280665
2016-09-05 23:42:39 +08:00
.word 0