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[llvm][MC][ARM] Don't autoresolve fixups
Removes logic that caused some fixups to be marked as resolved in the assembler without actually resolving them. Sometimes to resolve these fixups a relocation was needed, which was not generated, resulting in invalid code. Now in situations when the fixup cannot be resolved by the assembler, either a relocation is generated, or an error is produced. This was partially addressed previously (#72873, #73834) specifically for LDRx and ADR instructions, This patch expands it LDRD and VLDR, which should cover all instructions affected.
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9 files changed

+169
-19
lines changed

9 files changed

+169
-19
lines changed

‎llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp

Lines changed: 11 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -67,8 +67,6 @@ ARMAsmBackendELF::getFixupKind(StringRef Name) const {
6767
}
6868

6969
const MCFixupKindInfo &ARMAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
70-
unsigned IsPCRelConstant =
71-
MCFixupKindInfo::FKF_IsPCRel | MCFixupKindInfo::FKF_Constant;
7270
const static MCFixupKindInfo InfosLE[ARM::NumTargetFixupKinds] = {
7371
// This table *must* be in the order that the fixup_* kinds are defined in
7472
// ARMFixupKinds.h.
@@ -79,13 +77,14 @@ const MCFixupKindInfo &ARMAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
7977
MCFixupKindInfo::FKF_IsPCRel |
8078
MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
8179
{"fixup_arm_pcrel_10_unscaled", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
82-
{"fixup_arm_pcrel_10", 0, 32, IsPCRelConstant},
80+
{"fixup_arm_pcrel_10", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
8381
{"fixup_t2_pcrel_10", 0, 32,
8482
MCFixupKindInfo::FKF_IsPCRel |
8583
MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
8684
{"fixup_arm_pcrel_9", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
8785
{"fixup_t2_pcrel_9", 0, 32,
88-
IsPCRelConstant | MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
86+
MCFixupKindInfo::FKF_IsPCRel |
87+
MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
8988
{"fixup_arm_ldst_abs_12", 0, 32, 0},
9089
{"fixup_thumb_adr_pcrel_10", 0, 8,
9190
MCFixupKindInfo::FKF_IsPCRel |
@@ -140,19 +139,22 @@ const MCFixupKindInfo &ARMAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
140139
MCFixupKindInfo::FKF_IsPCRel |
141140
MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
142141
{"fixup_arm_pcrel_10_unscaled", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
143-
{"fixup_arm_pcrel_10", 0, 32, IsPCRelConstant},
142+
{"fixup_arm_pcrel_10", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
144143
{"fixup_t2_pcrel_10", 0, 32,
145144
MCFixupKindInfo::FKF_IsPCRel |
146145
MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
147146
{"fixup_arm_pcrel_9", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
148147
{"fixup_t2_pcrel_9", 0, 32,
149-
IsPCRelConstant | MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
148+
MCFixupKindInfo::FKF_IsPCRel |
149+
MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
150150
{"fixup_arm_ldst_abs_12", 0, 32, 0},
151151
{"fixup_thumb_adr_pcrel_10", 8, 8,
152-
IsPCRelConstant | MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
153-
{"fixup_arm_adr_pcrel_12", 0, 32, IsPCRelConstant},
152+
MCFixupKindInfo::FKF_IsPCRel |
153+
MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
154+
{"fixup_arm_adr_pcrel_12", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
154155
{"fixup_t2_adr_pcrel_12", 0, 32,
155-
IsPCRelConstant | MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
156+
MCFixupKindInfo::FKF_IsPCRel |
157+
MCFixupKindInfo::FKF_IsAlignedDownTo32Bits},
156158
{"fixup_arm_condbranch", 8, 24, MCFixupKindInfo::FKF_IsPCRel},
157159
{"fixup_arm_uncondbranch", 8, 24, MCFixupKindInfo::FKF_IsPCRel},
158160
{"fixup_t2_condbranch", 0, 32, MCFixupKindInfo::FKF_IsPCRel},

‎llvm/lib/Target/ARM/MCTargetDesc/ARMFixupKinds.h

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -28,7 +28,7 @@ enum Fixups {
2828
// immediate).
2929
fixup_arm_pcrel_10,
3030
// Equivalent to fixup_arm_pcrel_10, accounting for the short-swapped encoding
31-
// of Thumb2 instructions.
31+
// of Thumb2 instructions. Also used by LDRD in Thumb mode.
3232
fixup_t2_pcrel_10,
3333
// 9-bit PC relative relocation for symbol addresses used in VFP instructions
3434
// where bit 0 not encoded (so it's encoded as an 8-bit immediate).

‎llvm/test/MC/ARM/pcrel-arm-ldrd-relocs.s

Lines changed: 30 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,30 @@
1+
@ RUN: llvm-mc -filetype=obj -triple=armv7 %s -o %t
2+
@ RUN: llvm-readelf -r %t | FileCheck %s --check-prefix=ARM
3+
@ RUN: llvm-objdump -d --triple=armv7 %t | FileCheck %s --check-prefix=ARM_ADDEND
4+
@ RUN: llvm-mc -filetype=obj -triple=armebv7 %s -o %t
5+
@ RUN: llvm-readelf -r %t | FileCheck %s --check-prefix=ARM
6+
@ RUN: llvm-objdump -d --triple=armebv7 %t | FileCheck %s --check-prefix=ARM_ADDEND
7+
8+
.section .text.bar, "ax"
9+
.balign 4
10+
.global bar
11+
.type bar, %function
12+
13+
bar:
14+
ldrd r0, r1, foo1 @ arm_pcrel_10_unscaled
15+
ldrd r0, r1, foo2-8 @ arm_pcrel_10_unscaled
16+
bx lr
17+
18+
.section .data.foo, "a", %progbits
19+
.balign 4
20+
.global foo1
21+
.global foo2
22+
foo1:
23+
.word 0x11223344, 0x55667788
24+
foo2:
25+
.word 0x99aabbcc, 0xddeeff00
26+
27+
@ ARM: R_ARM_LDRS_PC_G0
28+
29+
@ ARM_ADDEND: ldrd r0, r1, [pc, #-8]
30+
@ ARM_ADDEND: ldrd r0, r1, [pc, #-16]

‎llvm/test/MC/ARM/pcrel-global.s

Lines changed: 1 addition & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -7,18 +7,14 @@
77
@ CHECK: There are no relocations in this file.
88

99
@ DISASM-LABEL: <bar>:
10-
@ DISASM-NEXT: ldr r0, [pc, #0x0] @ 0x8 <bar+0x4>
10+
@ DISASM-NEXT: ldr r0, [pc, #0x0] @ 0x4 <bar+0x4>
1111
@ DISASM-NEXT: add r0, pc
1212
@ DISASM-NEXT: .word 0xfffffffb
1313
@@ GNU assembler creates an R_ARM_REL32 referencing bar.
1414
@ DISASM-NOT: {{.}}
1515

1616
.syntax unified
1717

18-
.globl foo
19-
foo:
20-
vldr d0, foo @ arm_pcrel_10
21-
2218
.thumb
2319
.thumb_func
2420
.type bar, %function

‎llvm/test/MC/ARM/pcrel-ldr-relocs.s

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -34,10 +34,10 @@
3434
.global bar
3535
.type bar, %function
3636
bar:
37-
ldr r0, foo1
38-
ldrb r0, foo1
39-
ldr r0, foo2-8
40-
ldrb r0, foo1+8
37+
ldr r0, foo1 @ arm_ldst_pcrel_12 / t2_ldst_pcrel_12
38+
ldrb r0, foo1 @ arm_ldst_pcrel_12 / t2_ldst_pcrel_12
39+
ldr r0, foo2-8 @ arm_ldst_pcrel_12 / t2_ldst_pcrel_12
40+
ldrb r0, foo1+8 @ arm_ldst_pcrel_12 / t2_ldst_pcrel_12
4141
bx lr
4242

4343
.section .data.foo, "a", %progbits

‎llvm/test/MC/ARM/pcrel-ldrd-same-section.s

Lines changed: 39 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,39 @@
1+
@ RUN: llvm-mc -filetype=obj -o %t %s -triple=armv7
2+
@ RUN: llvm-readelf -r %t | FileCheck %s --check-prefix=RELOC
3+
@ RUN: llvm-objdump -d --triple=armv7 %t | FileCheck %s --check-prefix=ARM_OFFSET
4+
5+
@ RUN: llvm-mc -filetype=obj -o %t %s -triple=armebv7
6+
@ RUN: llvm-readelf -r %t | FileCheck %s --check-prefix=RELOC
7+
@ RUN: llvm-objdump -d --triple=armebv7 %t | FileCheck %s --check-prefix=ARM_OFFSET
8+
9+
@ RUN: llvm-mc -filetype=obj -o %t %s -triple=thumbv7
10+
@ RUN: llvm-readelf -r %t | FileCheck %s --check-prefix=RELOC
11+
@ RUN: llvm-objdump -d --triple=thumbv7 %t | FileCheck %s --check-prefix=THUMB_OFFSET
12+
13+
@ RUN: llvm-mc -filetype=obj -o %y %s -triple=thumbebv7
14+
@ RUN: llvm-readelf -r %t | FileCheck %s --check-prefix=RELOC
15+
@ RUN: llvm-objdump -d --triple=thumbebv7 %t | FileCheck %s --check-prefix=THUMB_OFFSET
16+
17+
baz:
18+
.word 0x11223344, 0x55667788
19+
label:
20+
21+
ldrd r0, r1, foo @ arm_pcrel_10_unscaled / t2_pcrel_10
22+
ldrd r0, r1, bar-8 @ arm_pcrel_10_unscaled / t2_pcrel_10
23+
24+
ldrd r0, r1, baz @ arm_pcrel_10_unscaled / t2_pcrel_10
25+
ldrd r0, r1, label-8 @ arm_pcrel_10_unscaled / t2_pcrel_10
26+
foo:
27+
.word 0x11223344, 0x55667788
28+
bar:
29+
30+
@ RELOC: There are no relocations in this file.
31+
32+
@ ARM_OFFSET: ldrd r0, r1, [pc, #8] @ 0x18 <foo>
33+
@ ARM_OFFSET: ldrd r0, r1, [pc, #4] @ 0x18 <foo>
34+
@ ARM_OFFSET: ldrd r0, r1, [pc, #-24] @ 0x0 <baz>
35+
@ ARM_OFFSET: ldrd r0, r1, [pc, #-28] @ 0x0 <baz>
36+
@ THUMB_OFFSET: ldrd r0, r1, [pc, #12] @ 0x18 <foo>
37+
@ THUMB_OFFSET: ldrd r0, r1, [pc, #8] @ 0x18 <foo>
38+
@ THUMB_OFFSET: ldrd r0, r1, [pc, #-20] @ 0x0 <baz>
39+
@ THUMB_OFFSET: ldrd r0, r1, [pc, #-24] @ 0x0 <baz>

‎llvm/test/MC/ARM/pcrel-thumb-ldrd-relocs.s

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,6 @@
1+
@ RUN: not llvm-mc -filetype=obj -o /dev/null %s 2>&1 -triple=thumbv7 | FileCheck %s
2+
@ RUN: not llvm-mc -filetype=obj -o /dev/null %s 2>&1 -triple=thumbebv7 | FileCheck %s
3+
4+
ldrd r0, r1, foo
5+
6+
@ CHECK: :[[#@LINE-2]]:4: error: unsupported relocation type

‎llvm/test/MC/ARM/pcrel-vldr-diff-section.s

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
1+
@ RUN: not llvm-mc -filetype=obj -o /dev/null %s 2>&1 -triple=armv8.2a-eabi | FileCheck %s
2+
@ RUN: not llvm-mc -filetype=obj -o /dev/null %s 2>&1 -triple=armebv8.2a-eabi | FileCheck %s
3+
@ RUN: not llvm-mc -filetype=obj -o /dev/null %s 2>&1 -triple=thumbv8.2a-eabi | FileCheck %s
4+
@ RUN: not llvm-mc -filetype=obj -o /dev/null %s 2>&1 -triple=thumbebv8.2a-eabi | FileCheck %s
5+
6+
.arch_extension fp16
7+
8+
vldr s0, foo @ arm_pcrel_10 / t2_pcrel_10
9+
vldr d0, foo @ arm_pcrel_10 / t2_pcrel_10
10+
vldr.16 s0,foo @ arm_pcrel_9 / t2_pcrel_9
11+
12+
@ CHECK: :[[#@LINE-4]]:1: error: unsupported relocation type
13+
@ CHECK: :[[#@LINE-4]]:1: error: unsupported relocation type
14+
@ CHECK: :[[#@LINE-4]]:1: error: unsupported relocation type
15+

‎llvm/test/MC/ARM/pcrel-vldr-same-section.s

Lines changed: 62 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,62 @@
1+
@ RUN: llvm-mc -filetype=obj -o %t %s -triple=armv8.2a-eabi
2+
@ RUN: llvm-readelf -r %t | FileCheck %s --check-prefix=RELOC
3+
@ RUN: llvm-objdump -d --triple=armv8.2a-eabi --mattr=+fullfp16 %t | FileCheck %s --check-prefix=ARM_OFFSET
4+
@ RUN: llvm-mc -filetype=obj -o %t %s -triple=armebv8.2a-eabi
5+
@ RUN: llvm-readelf -r %t | FileCheck %s --check-prefix=RELOC
6+
@ RUN: llvm-objdump -d --triple=armebv8.2a-eabi --mattr=+fullfp16 %t | FileCheck %s --check-prefix=ARM_OFFSET
7+
@ RUN: llvm-mc -filetype=obj -o %t %s -triple=thumbv8.2a-eabi
8+
@ RUN: llvm-readelf -r %t | FileCheck %s --check-prefix=RELOC
9+
@ RUN: llvm-objdump -d --triple=thumbv8.2a-eabi --mattr=+fullfp16 %t | FileCheck %s --check-prefix=THUMB_OFFSET
10+
@ RUN: llvm-mc -filetype=obj -o %y %s -triple=thumbebv8.2a-eabi
11+
@ RUN: llvm-readelf -r %t | FileCheck %s --check-prefix=RELOC
12+
@ RUN: llvm-objdump -d --triple=thumbebv8.2a-eabi --mattr=+fullfp16 %t | FileCheck %s --check-prefix=THUMB_OFFSET
13+
14+
.arch_extension fp16
15+
baz:
16+
.word 0x11223344, 0x55667788
17+
label:
18+
19+
vldr s0, foo @ arm_pcrel_10 / t2_pcrel_10
20+
vldr d0, foo @ arm_pcrel_10 / t2_pcrel_10
21+
vldr.16 s0, foo @ arm_pcrel_9 / t2_pcrel_9
22+
vldr s0, bar-8
23+
vldr d0, bar-8
24+
vldr.16 s0, bar-8
25+
vldr s0, baz
26+
vldr d0, baz
27+
vldr.16 s0, baz
28+
vldr s0, label-8
29+
vldr d0, label-8
30+
vldr.16 s0, label-8
31+
32+
foo:
33+
.word 0x11223344, 0x55667788
34+
bar:
35+
36+
@ RELOC: There are no relocations in this file.
37+
38+
@ ARM_OFFSET: vldr s0, [pc, #40] @ 0x38 <foo>
39+
@ ARM_OFFSET: vldr d0, [pc, #36] @ 0x38 <foo>
40+
@ ARM_OFFSET: vldr.16 s0, [pc, #32] @ 0x38 <foo>
41+
@ ARM_OFFSET: vldr s0, [pc, #28] @ 0x38 <foo>
42+
@ ARM_OFFSET: vldr d0, [pc, #24] @ 0x38 <foo>
43+
@ ARM_OFFSET: vldr.16 s0, [pc, #20] @ 0x38 <foo>
44+
@ ARM_OFFSET: vldr s0, [pc, #-40] @ 0x0 <baz>
45+
@ ARM_OFFSET: vldr d0, [pc, #-44] @ 0x0 <baz>
46+
@ ARM_OFFSET: vldr.16 s0, [pc, #-48] @ 0x0 <baz>
47+
@ ARM_OFFSET: vldr s0, [pc, #-52] @ 0x0 <baz>
48+
@ ARM_OFFSET: vldr d0, [pc, #-56] @ 0x0 <baz>
49+
@ ARM_OFFSET: vldr.16 s0, [pc, #-60] @ 0x0 <baz>
50+
@ THUMB_OFFSET: ldr s0, [pc, #44] @ 0x38 <foo>
51+
@ THUMB_OFFSET: ldr d0, [pc, #40] @ 0x38 <foo>
52+
@ THUMB_OFFSET: ldr.16 s0, [pc, #36] @ 0x38 <foo>
53+
@ THUMB_OFFSET: ldr s0, [pc, #32] @ 0x38 <foo>
54+
@ THUMB_OFFSET: ldr d0, [pc, #28] @ 0x38 <foo>
55+
@ THUMB_OFFSET: ldr.16 s0, [pc, #24] @ 0x38 <foo>
56+
@ THUMB_OFFSET: vldr s0, [pc, #-36] @ 0x0 <baz>
57+
@ THUMB_OFFSET: vldr d0, [pc, #-40] @ 0x0 <baz>
58+
@ THUMB_OFFSET: vldr.16 s0, [pc, #-44] @ 0x0 <baz>
59+
@ THUMB_OFFSET: vldr s0, [pc, #-48] @ 0x0 <baz>
60+
@ THUMB_OFFSET: vldr d0, [pc, #-52] @ 0x0 <baz>
61+
@ THUMB_OFFSET: vldr.16 s0, [pc, #-56] @ 0x0 <baz>
62+

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