llvm-project/llvm/test/MC/Mips/sort-relocation-table.s
Fangrui Song 59721f2326
[MIPS] Optimize sortRelocs for o32
The o32 ABI specifies:

> Each relocation type of R_MIPS_HI16 must have an associated R_MIPS_LO16 entry immediately following it in the list of relocations. [...] the addend AHL is computed as (AHI << 16) + (short)ALO

In practice, the high-part and low-part relocations may not be adjacent
in assembly files, requiring the assembler to reorder relocations.
http://reviews.llvm.org/D19718 performed the reordering, but did not
optimize for the common case where a %lo immediately follows its
matching %hi. The quadratic time complexity could make sections with
many relocations very slow to process.

This patch implements the fast path, simplifies the code, and makes the
behavior more similar to GNU assembler (for the .rel.mips_hilo_8b test).
We also remove `OriginalSymbol`, removing overhead for other targets.

Fix #104562

Pull Request: https://github.com/llvm/llvm-project/pull/104723
2024-08-23 00:05:20 -07:00

399 lines
14 KiB
ArmAsm

# RUN: llvm-mc -filetype=obj -triple=mipsel %s | llvm-readobj -r - | FileCheck %s
# Test the order of records in the relocation table.
#
# MIPS has a few relocations that have an AHL component in the expression used
# to evaluate them. This AHL component is an addend with the same number of
# bits as a symbol value but not all of our ABI's are able to supply a
# sufficiently sized addend in a single relocation.
#
# The O32 ABI for example, uses REL relocations which store the addend in the
# section data. All the relocations with AHL components affect 16-bit fields
# so the addend is limited to 16-bit. This ABI resolves the limitation by
# linking relocations (e.g. R_MIPS_HI16 and R_MIPS_LO16) and distributing the
# addend between the linked relocations. The ABI mandates that such relocations
# must be next to each other in a particular order (e.g. R_MIPS_HI16 must be
# followed by a matching R_MIPS_LO16) but the rule is less strict in practice.
#
# See MipsELFObjectWriter.cpp for a full description of the rules.
#
# TODO: Add mips16 and micromips tests.
# HILO 1: HI/LO already match
.section .mips_hilo_1, "ax", @progbits
lui $2, %hi(sym1)
addiu $2, $2, %lo(sym1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_1 {
# CHECK-NEXT: 0x0 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x4 R_MIPS_LO16 sym1
# CHECK-NEXT: }
# HILO 2: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
.section .mips_hilo_2, "ax", @progbits
addiu $2, $2, %lo(sym1)
lui $2, %hi(sym1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_2 {
# CHECK-NEXT: 0x4 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x0 R_MIPS_LO16 sym1
# CHECK-NEXT: }
# HILO 3: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
# The second relocation matches if the symbol is the same.
.section .mips_hilo_3, "ax", @progbits
addiu $2, $2, %lo(sym1)
lui $2, %hi(sym2)
addiu $2, $2, %lo(sym2)
lui $2, %hi(sym1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_3 {
# CHECK-NEXT: 0xC R_MIPS_HI16 sym1
# CHECK-NEXT: 0x0 R_MIPS_LO16 sym1
# CHECK-NEXT: 0x4 R_MIPS_HI16 sym2
# CHECK-NEXT: 0x8 R_MIPS_LO16 sym2
# CHECK-NEXT: }
# HILO 3b: Same as 3 but a different starting order.
.section .mips_hilo_3b, "ax", @progbits
addiu $2, $2, %lo(sym1)
lui $2, %hi(sym1)
addiu $2, $2, %lo(sym2)
lui $2, %hi(sym2)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_3b {
# CHECK-NEXT: 0x4 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x0 R_MIPS_LO16 sym1
# CHECK-NEXT: 0xC R_MIPS_HI16 sym2
# CHECK-NEXT: 0x8 R_MIPS_LO16 sym2
# CHECK-NEXT: }
# HILO 4: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
# The second relocation matches if the symbol is the same and the
# offset is the same.
.section .mips_hilo_4, "ax", @progbits
addiu $2, $2, %lo(sym1)
addiu $2, $2, %lo(sym1+4)
lui $2, %hi(sym1+4)
lui $2, %hi(sym1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_4 {
# CHECK-NEXT: 0xC R_MIPS_HI16 sym1
# CHECK-NEXT: 0x0 R_MIPS_LO16 sym1
# CHECK-NEXT: 0x8 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x4 R_MIPS_LO16 sym1
# CHECK-NEXT: }
# HILO 5: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
# The second relocation matches if the symbol is the same and the
# offset is greater or equal. Exact matches are preferred so both
# R_MIPS_HI16's match the same R_MIPS_LO16.
.section .mips_hilo_5, "ax", @progbits
lui $2, %hi(sym1)
lui $2, %hi(sym1)
addiu $2, $2, %lo(sym1+1)
addiu $2, $2, %lo(sym1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_5 {
# CHECK-NEXT: 0x8 R_MIPS_LO16 sym1
# CHECK-NEXT: 0x0 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x4 R_MIPS_HI16 sym1
# CHECK-NEXT: 0xC R_MIPS_LO16 sym1
# CHECK-NEXT: }
# HILO 6: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
# The second relocation matches if the symbol is the same and the
# offset is greater or equal. Smaller offsets are preferred so both
# R_MIPS_HI16's still match the same R_MIPS_LO16.
.section .mips_hilo_6, "ax", @progbits
lui $2, %hi(sym1)
lui $2, %hi(sym1)
addiu $2, $2, %lo(sym1+2)
addiu $2, $2, %lo(sym1+1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_6 {
# CHECK-NEXT: 0x8 R_MIPS_LO16 sym1
# CHECK-NEXT: 0x0 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x4 R_MIPS_HI16 sym1
# CHECK-NEXT: 0xC R_MIPS_LO16 sym1
# CHECK-NEXT: }
# HILO 7: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
# The second relocation matches if the symbol is the same and the
# offset is greater or equal so that the carry bit is correct. The two
# R_MIPS_HI16's therefore match different R_MIPS_LO16's.
.section .mips_hilo_7, "ax", @progbits
addiu $2, $2, %lo(sym1+1)
addiu $2, $2, %lo(sym1+6)
lui $2, %hi(sym1+4)
lui $2, %hi(sym1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_7 {
# CHECK-NEXT: 0xC R_MIPS_HI16 sym1
# CHECK-NEXT: 0x0 R_MIPS_LO16 sym1
# CHECK-NEXT: 0x8 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x4 R_MIPS_LO16 sym1
# CHECK-NEXT: }
# HILO 8: R_MIPS_LO16's may be orphaned.
.section .mips_hilo_8, "ax", @progbits
lw $2, %lo(sym1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_8 {
# CHECK-NEXT: 0x0 R_MIPS_LO16 sym1
# CHECK-NEXT: }
# HILO 8b: Another example of 8. The R_MIPS_LO16 at 0x4 is orphaned.
.section .mips_hilo_8b, "ax", @progbits
lw $2, %lo(sym1)
lw $2, %lo(sym1)
lui $2, %hi(sym1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_8b {
# CHECK-NEXT: 0x0 R_MIPS_LO16 sym1
# CHECK-NEXT: 0x8 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x4 R_MIPS_LO16 sym1
# CHECK-NEXT: }
# HILO 9: R_MIPS_HI16's don't need a matching R_MIPS_LO16 to immediately follow
# so long as there is one after the R_MIPS_HI16 somewhere. This isn't
# permitted by the ABI specification but has been allowed in practice
# for a very long time. The R_MIPS_HI16's should be ordered by the
# address they affect for purely cosmetic reasons.
.section .mips_hilo_9, "ax", @progbits
lw $2, %lo(sym1)
lui $2, %hi(sym1)
lui $2, %hi(sym1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_9 {
# CHECK-NEXT: 0x4 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x8 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x0 R_MIPS_LO16 sym1
# CHECK-NEXT: }
# HILO 10: R_MIPS_HI16's must have a matching R_MIPS_LO16 somewhere though.
# When this is impossible we have two possible bad behaviours
# depending on the linker implementation:
# * The linker silently computes the wrong value using a partially
# matching R_MIPS_LO16.
# * The linker rejects the relocation table as invalid.
# The latter is preferable since it's far easier to detect and debug so
# check that we encourage this behaviour by putting invalid
# R_MIPS_HI16's at the end of the relocation table where the risk of a
# partial match is very low.
.section .mips_hilo_10, "ax", @progbits
lui $2, %hi(sym1)
lw $2, %lo(sym1)
lui $2, %hi(sym2)
lui $2, %hi(sym3)
lw $2, %lo(sym3)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_10 {
# CHECK-NEXT: 0x0 R_MIPS_HI16 sym1
# CHECK-NEXT: 0x4 R_MIPS_LO16 sym1
# CHECK-NEXT: 0xC R_MIPS_HI16 sym3
# CHECK-NEXT: 0x10 R_MIPS_LO16 sym3
# CHECK-NEXT: 0x8 R_MIPS_HI16 sym2
# CHECK-NEXT: }
# Now do the same tests for GOT/LO.
# The rules only apply to R_MIPS_GOT16 on local symbols which are also
# rewritten into section relative relocations.
# GOTLO 1: GOT/LO already match
.section .mips_gotlo_1, "ax", @progbits
lui $2, %got(local1)
addiu $2, $2, %lo(local1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_1 {
# CHECK-NEXT: 0x0 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x4 R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 2: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
.section .mips_gotlo_2, "ax", @progbits
addiu $2, $2, %lo(local1)
lui $2, %got(local1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_2 {
# CHECK-NEXT: 0x4 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x0 R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 3: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
# The second relocation matches if the symbol is the same.
.section .mips_gotlo_3, "ax", @progbits
addiu $2, $2, %lo(local1)
lui $2, %got(local2)
addiu $2, $2, %lo(local2)
lui $2, %got(local1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_3 {
# CHECK-NEXT: 0xC R_MIPS_GOT16 .text
# CHECK-NEXT: 0x0 R_MIPS_LO16 .text
# CHECK-NEXT: 0x4 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x8 R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 3b: Same as 3 but a different starting order.
.section .mips_gotlo_3b, "ax", @progbits
addiu $2, $2, %lo(local1)
lui $2, %got(local1)
addiu $2, $2, %lo(local2)
lui $2, %got(local2)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_3b {
# CHECK-NEXT: 0x4 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x0 R_MIPS_LO16 .text
# CHECK-NEXT: 0xC R_MIPS_GOT16 .text
# CHECK-NEXT: 0x8 R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 4: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
# The second relocation matches if the symbol is the same and the
# offset is the same.
.section .mips_gotlo_4, "ax", @progbits
addiu $2, $2, %lo(local1)
addiu $2, $2, %lo(local1+4)
lui $2, %got(local1+4)
lui $2, %got(local1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_4 {
# CHECK-NEXT: 0xC R_MIPS_GOT16 .text
# CHECK-NEXT: 0x0 R_MIPS_LO16 .text
# CHECK-NEXT: 0x8 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x4 R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 5: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
# The second relocation matches if the symbol is the same and the
# offset is greater or equal. Exact matches are preferred so both
# R_MIPS_GOT16's match the same R_MIPS_LO16.
.section .mips_gotlo_5, "ax", @progbits
lui $2, %got(local1)
lui $2, %got(local1)
addiu $2, $2, %lo(local1+1)
addiu $2, $2, %lo(local1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_5 {
# CHECK-NEXT: 0x8 R_MIPS_LO16 .text
# CHECK-NEXT: 0x0 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x4 R_MIPS_GOT16 .text
# CHECK-NEXT: 0xC R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 6: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
# The second relocation matches if the symbol is the same and the
# offset is greater or equal. Smaller offsets are preferred so both
# R_MIPS_GOT16's still match the same R_MIPS_LO16.
.section .mips_gotlo_6, "ax", @progbits
lui $2, %got(local1)
lui $2, %got(local1)
addiu $2, $2, %lo(local1+2)
addiu $2, $2, %lo(local1+1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_6 {
# CHECK-NEXT: 0x8 R_MIPS_LO16 .text
# CHECK-NEXT: 0x0 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x4 R_MIPS_GOT16 .text
# CHECK-NEXT: 0xC R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 7: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
# The second relocation matches if the symbol is the same and the
# offset is greater or equal so that the carry bit is correct. The two
# R_MIPS_GOT16's therefore match different R_MIPS_LO16's.
.section .mips_gotlo_7, "ax", @progbits
addiu $2, $2, %lo(local1+1)
addiu $2, $2, %lo(local1+6)
lui $2, %got(local1+4)
lui $2, %got(local1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_7 {
# CHECK-NEXT: 0xC R_MIPS_GOT16 .text
# CHECK-NEXT: 0x0 R_MIPS_LO16 .text
# CHECK-NEXT: 0x8 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x4 R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 8: R_MIPS_LO16's may be orphaned.
.section .mips_gotlo_8, "ax", @progbits
lw $2, %lo(local1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_8 {
# CHECK-NEXT: 0x0 R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 8b: Another example of 8. The R_MIPS_LO16 at 0x4 is orphaned.
.section .mips_gotlo_8b, "ax", @progbits
lw $2, %lo(local1)
lw $2, %lo(local1)
lui $2, %got(local1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_8b {
# CHECK-NEXT: 0x0 R_MIPS_LO16 .text
# CHECK-NEXT: 0x8 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x4 R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 9: R_MIPS_GOT16's don't need a matching R_MIPS_LO16 to immediately
# follow so long as there is one after the R_MIPS_GOT16 somewhere.
# This isn't permitted by the ABI specification but has been allowed
# in practice for a very long time. The R_MIPS_GOT16's should be
# ordered by the address they affect for purely cosmetic reasons.
.section .mips_gotlo_9, "ax", @progbits
lw $2, %lo(local1)
lui $2, %got(local1)
lui $2, %got(local1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_9 {
# CHECK-NEXT: 0x4 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x8 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x0 R_MIPS_LO16 .text
# CHECK-NEXT: }
# GOTLO 10: R_MIPS_GOT16's must have a matching R_MIPS_LO16 somewhere though.
# When this is impossible we have two possible bad behaviours
# depending on the linker implementation:
# * The linker silently computes the wrong value using a partially
# matching R_MIPS_LO16.
# * The linker rejects the relocation table as invalid.
# The latter is preferable since it's far easier to detect and debug
# so check that we encourage this behaviour by putting invalid
# R_MIPS_GOT16's at the end of the relocation table where the risk of
# a partial match is very low.
.section .mips_gotlo_10, "ax", @progbits
lui $2, %got(local1)
lw $2, %lo(local1)
lui $2, %got(local2)
lui $2, %got(local3)
lw $2, %lo(local3)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_10 {
# CHECK-NEXT: 0x0 R_MIPS_GOT16 .text
# CHECK-NEXT: 0x4 R_MIPS_LO16 .text
# CHECK-NEXT: 0x8 R_MIPS_GOT16 .text
# CHECK-NEXT: 0xC R_MIPS_GOT16 .text
# CHECK-NEXT: 0x10 R_MIPS_LO16 .text
# CHECK-NEXT: }
# Finally, do test 2 for R_MIPS_GOT16 on external symbols to prove they are
# exempt from the rules for local symbols.
# External GOTLO 2: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
.section .mips_ext_gotlo_2, "ax", @progbits
addiu $2, $2, %lo(sym1)
lui $2, %got(sym1)
# CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_ext_gotlo_2 {
# CHECK-NEXT: 0x0 R_MIPS_LO16 sym1
# CHECK-NEXT: 0x4 R_MIPS_GOT16 sym1
# CHECK-NEXT: }
# Define some local symbols.
.text
nop
local1: nop
local2: nop
local3: nop