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[PPC64] Sort .toc sections accessed with small code model relocs clos…
…e to .got. Small code model global variable access on PPC64 has a very limited range of addressing. The instructions the relocations are used on add an offset in the range [-0x8000, 0x7FFC] to the toc pointer which points to .got +0x8000, giving an addressable range of [.got, .got + 0xFFFC]. While user code can be recompiled with medium and large code models when the binary grows too large for small code model, there are small code model relocations in the crt files and libgcc.a which are typically shipped with the distros, and the ABI dictates that linkers must allow linking of relocatable object files using different code models. To minimze the chance of relocation overflow, any file that contains a small code model relocation should have its .toc section placed closer to the .got then any .toc from a file without small code model relocations. Differential Revision: https://reviews.llvm.org/D56920 llvm-svn: 351978
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Sean Fertile
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Jan 23, 2019
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,23 @@ | ||
.text | ||
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.global set | ||
.type set,@function | ||
set: | ||
.Lgep: | ||
addis 2, 12, .TOC.-.Lgep@ha | ||
addi 2, 2, .TOC.-.Lgep@l | ||
.Llep: | ||
.localentry set, .Llep-.Lgep | ||
addis 5, 2, .LC0@toc@ha | ||
addis 6, 2, .LC1@toc@ha | ||
ld 5, .LC0@toc@l(5) | ||
ld 6, .LC1@toc@l(6) | ||
stw 3, 0(5) | ||
stw 4, 0(6) | ||
blr | ||
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.section .toc,"aw",@progbits | ||
.LC0: | ||
.tc c[TC],c | ||
.LC1: | ||
.tc d[TC],d |
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,41 @@ | ||
.text | ||
.global getA | ||
.type getA,@function | ||
getA: | ||
.LgepA: | ||
addis 2, 12, .TOC.-.LgepA@ha | ||
addi 2, 2, .TOC.-.LgepA@l | ||
.LlepA: | ||
.localentry getA, .LlepA-.LgepA | ||
ld 3, .LC0@toc(2) | ||
lwa 3, 0(3) | ||
blr | ||
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.global getB | ||
.type getB,@function | ||
getB: | ||
.LgepB: | ||
addis 2, 12, .TOC.-.LgepB@ha | ||
addi 2, 2, .TOC.-.LgepB@l | ||
.LlepB: | ||
.localentry getB, .LlepB-.LgepB | ||
ld 3, .LC1@toc(2) | ||
lwa 3, 0(3) | ||
blr | ||
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.section .toc,"aw",@progbits | ||
.LC0: | ||
.tc a[TC],a | ||
.LConst1: | ||
.quad 0xa | ||
.LC1: | ||
.tc b[TC],b | ||
.Lconst2: | ||
.quad 0xaabbccddeeff | ||
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.type b,@object | ||
.data | ||
.global b | ||
b: | ||
.long 22 | ||
.size b, 4 |
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,18 @@ | ||
.text | ||
.global getRodata | ||
.type getRodata,@function | ||
getRodata: | ||
.Lgep: | ||
addis 2, 12, .TOC.-.Lgep@ha | ||
addi 2, 2, .TOC.-.Lgep@l | ||
.Llep: | ||
.localentry getRodata, .Llep-.Lgep | ||
lwa 3, .LC0@toc(2) | ||
blr | ||
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.section .rodata,"aMS",@progbits,8 | ||
.quad _start | ||
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.section .toc,"aw",@progbits | ||
.LC0: | ||
.tc .rodata[TC], .rodata |
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@@ -0,0 +1,108 @@ | ||
# REQUIRES: ppc | ||
# RUN: llvm-mc -filetype=obj -triple=powerpc64le-unknown-linux %s -o %t1.o | ||
# RUN: llvm-mc -filetype=obj -triple=powerpc64le-unknown-linux %p/Inputs/ppc64-sort-small-cm-relocs-input2.s -o %t2.o | ||
# RUN: llvm-mc -filetype=obj -triple=powerpc64le-unknown-linux %p/Inputs/ppc64-sort-small-cm-relocs-input3.s -o %t3.o | ||
# RUN: llvm-mc -filetype=obj -triple=powerpc64le-unknown-linux %p/Inputs/ppc64-sort-small-cm-relocs-input4.s -o %t4.o | ||
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# RUN: ld.lld %t1.o %t2.o %t3.o %t4.o -o %t -Map=%t.map | ||
# RUN: FileCheck %s < %t.map | ||
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# Test an alternate link order. | ||
# RUN: ld.lld %t2.o %t3.o %t4.o %t1.o -o %t -Map=%t.map | ||
# RUN: FileCheck %s -check-prefix=ALTERNATE < %t.map | ||
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# If a linker script has a sections command then allow that to override the | ||
# default sorting behavior. | ||
# RUN: echo "SECTIONS { \ | ||
# RUN: .toc : { \ | ||
# RUN: */ppc64-sort-small-cm-relocs.s.tmp4.o(.toc*) \ | ||
# RUN: */ppc64-sort-small-cm-relocs.s.tmp1.o(.toc*) \ | ||
# RUN: *(.toc*) \ | ||
# RUN: } \ | ||
# RUN: } " > %t.script | ||
# RUN: ld.lld %t1.o %t2.o %t3.o %t4.o -o %t -script %t.script -Map=%t.map | ||
# RUN: FileCheck %s -check-prefix=SEC-CMD < %t.map | ||
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# RUN: echo "SECTIONS { .text : {*(.text*)} } " > %t.script | ||
# RUN: ld.lld %t1.o %t2.o %t3.o %t4.o -o %t -script %t.script -Map=%t.map | ||
# RUN: FileCheck %s -check-prefix=SEC-CMD2 < %t.map | ||
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# Default sort if the linker script does not have a sections command. | ||
# RUN: echo "" > %t.script | ||
# RUN: ld.lld %t1.o %t2.o %t3.o %t4.o -o %t -script %t.script -Map=%t.map | ||
# RUN: FileCheck %s -check-prefix=NOSEC < %t.map | ||
.text | ||
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.global _start | ||
.type _start,@function | ||
_start: | ||
li 3, 55 | ||
blr | ||
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.type a,@object | ||
.data | ||
.global a | ||
a: | ||
.long 10 | ||
.size a, 4 | ||
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.type c,@object | ||
.data | ||
.global c | ||
c: | ||
.long 55 | ||
.size c, 4 | ||
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.type d,@object | ||
.global d | ||
d: | ||
.long 33 | ||
.size d, 4 | ||
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# .toc section contains only some constants. | ||
.section .toc,"aw",@progbits | ||
.quad 0xa1a1a1a1a1a1a1a1 | ||
.quad 0xb2b2b2b2b2b2b2b2 | ||
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# Input files tmp3.o and tmp4.o contain small code model relocs. | ||
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# CHECK: .got | ||
# CHECK-NEXT: <internal>:(.got) | ||
# CHECK-NEXT: .toc | ||
# CHECK-NEXT: {{.*}}3.o:(.toc) | ||
# CHECK-NEXT: {{.*}}4.o:(.toc) | ||
# CHECK-NEXT: {{.*}}1.o:(.toc) | ||
# CHECK-NEXT: {{.*}}2.o:(.toc) | ||
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# ALTERNATE: .got | ||
# ALTERNATE-NEXT: <internal>:(.got) | ||
# ALTERNATE-NEXT: .toc | ||
# ALTERNATE-NEXT: {{.*}}3.o:(.toc) | ||
# ALTERNATE-NEXT: {{.*}}4.o:(.toc) | ||
# ALTERNATE-NEXT: {{.*}}2.o:(.toc) | ||
# ALTERNATE-NEXT: {{.*}}1.o:(.toc) | ||
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# SEC-CMD: .got | ||
# SEC-CMD-NEXT: <internal>:(.got) | ||
# SEC-CMD-NEXT: .toc | ||
# SEC-CMD-NEXT: {{.*}}4.o:(.toc) | ||
# SEC-CMD-NEXT: {{.*}}1.o:(.toc) | ||
# SEC-CMD-NEXT: {{.*}}2.o:(.toc) | ||
# SEC-CMD-NEXT: {{.*}}3.o:(.toc) | ||
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# SEC-CMD2: .got | ||
# SEC-CMD2-NEXT: <internal>:(.got) | ||
# SEC-CMD2-NEXT: .toc | ||
# SEC-CMD2-NEXT: {{.*}}1.o:(.toc) | ||
# SEC-CMD2-NEXT: {{.*}}2.o:(.toc) | ||
# SEC-CMD2-NEXT: {{.*}}3.o:(.toc) | ||
# SEC-CMD2-NEXT: {{.*}}4.o:(.toc) | ||
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# NOSEC: .got | ||
# NOSEC-NEXT: <internal>:(.got) | ||
# NOSEC-NEXT: .toc | ||
# NOSEC-NEXT: {{.*}}3.o:(.toc) | ||
# NOSEC-NEXT: {{.*}}4.o:(.toc) | ||
# NOSEC-NEXT: {{.*}}1.o:(.toc) | ||
# NOSEC-NEXT: {{.*}}2.o:(.toc) | ||
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