[lld] [lld][AArch64][ELF][PAC] Support AUTH relocations and AUTH ELF marking (PR #72714)

[Fangrui Song via llvm-commits]

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@@ -0,0 +1,114 @@
+# REQUIRES: aarch64
+
+# RUN: llvm-mc -filetype=obj -triple=aarch64 %p/Inputs/shared2.s -o %t.so.o
+# RUN: ld.lld -shared %t.so.o -soname=so -o %t.so
+# RUN: llvm-mc -filetype=obj -triple=aarch64 %s -o %t.o
+
+# RUN: ld.lld -pie -z nopack-relative-relocs %t.o %t.so -o %t2
+# RUN: llvm-readobj -r %t2 | FileCheck --check-prefix=UNPACKED %s
+
+# UNPACKED:          Section ({{.+}}) .rela.dyn {
+# UNPACKED-NEXT:       0x30440 R_AARCH64_AUTH_RELATIVE - 0x1
+# UNPACKED-NEXT:       0x30448 R_AARCH64_AUTH_RELATIVE - 0x2
+# UNPACKED-NEXT:       0x30450 R_AARCH64_AUTH_RELATIVE - 0x3
+# UNPACKED-NEXT:       0x30458 R_AARCH64_AUTH_RELATIVE - 0x12345678
+# UNPACKED-NEXT:       0x30460 R_AARCH64_AUTH_RELATIVE - 0x123456789A
+# UNPACKED-NEXT:       0x30479 R_AARCH64_AUTH_RELATIVE - 0x4
+# UNPACKED-NEXT:       0x30482 R_AARCH64_AUTH_RELATIVE - 0x5
+# UNPACKED-NEXT:       0x30468 R_AARCH64_AUTH_ABS64 zed2 0x0
+# UNPACKED-NEXT:       0x30470 R_AARCH64_AUTH_ABS64 bar2 0x0
+# UNPACKED-NEXT:     }
+
+# RUN: ld.lld -pie -z pack-relative-relocs %t.o %t.so -o %t2
+# RUN: llvm-readelf -S --dynamic-table %t2 | FileCheck --check-prefix=RELR-HEADERS %s
+
+# RELR-HEADERS:      Section Headers:
+# RELR-HEADERS-NEXT: Name Type Address Off Size ES Flg Lk Inf Al
+# RELR-HEADERS:      .relr.auth.dyn AARCH64_AUTH_RELR {{0*}}[[ADDR:.*]] {{0*}}[[ADDR]] 000018 08 A 0 0 8
+
+# RELR-HEADERS:      Dynamic section at offset 0x310 contains 16 entries
+# RELR-HEADERS:      0x0000000070000012 (AARCH64_AUTH_RELR) 0x[[ADDR]]
+# RELR-HEADERS-NEXT: 0x0000000070000011 (AARCH64_AUTH_RELRSZ) 24 (bytes)
+# RELR-HEADERS-NEXT: 0x0000000070000013 (AARCH64_AUTH_RELRENT) 8 (bytes)
+
+# RUN: llvm-readobj -r --raw-relr %t2 | FileCheck --check-prefix=RAW-RELR %s
+
+## SHT_RELR section contains address/bitmap entries
+## encoding the offsets for relative relocation.
+
+# RAW-RELR:           Section ({{.+}}) .relr.auth.dyn {
+# RAW-RELR-NEXT:      0x30410
+# RAW-RELR-NEXT:      0xF
+# RAW-RELR-NEXT:      0x30452
+# RAW-RELR-NEXT:      }
+
+# RUN: llvm-readobj -r %t2 | FileCheck --check-prefix=RELR %s
+
+## Decoded SHT_RELR section is same as UNPACKED,
+## but contains only the relative relocations.
+## Any relative relocations with odd offset stay in SHT_RELA.
+
+# RELR:      Section ({{.+}}) .rela.dyn {
+# RELR-NEXT:   0x30430 R_AARCH64_AUTH_RELATIVE - 0x123456789A
+# RELR-NEXT:   0x30449 R_AARCH64_AUTH_RELATIVE - 0x4
+# RELR-NEXT:   0x30438 R_AARCH64_AUTH_ABS64 zed2 0x0
+# RELR-NEXT:   0x30440 R_AARCH64_AUTH_ABS64 bar2 0x0
+# RELR-NEXT: }
+# RELR-NEXT: Section ({{.+}}) .relr.auth.dyn {
+# RELR-NEXT:   0x30410 R_AARCH64_RELATIVE -
+# RELR-NEXT:   0x30418 R_AARCH64_RELATIVE -
+# RELR-NEXT:   0x30420 R_AARCH64_RELATIVE -
+# RELR-NEXT:   0x30428 R_AARCH64_RELATIVE -
+# RELR-NEXT:   0x30452 R_AARCH64_RELATIVE -
+# RELR-NEXT: }
+
+# RUN: llvm-readobj -x .test %t2 | FileCheck --check-prefix=HEX %s
+
+# HEX:      Hex dump of section '.test':
+# HEX-NEXT: 0x00030410 01000000 2a000020 02000000 2b000000
+##                     ^^^^^^^^ Addend = 1
+##                              ^^^^ Discr = 42
+##                                    ^^ Key (bits 5..6) = DA
+##                                       ^^^^^^^^ Addend = 2
+##                                                ^^^^ Discr = 43
+##                                                      ^^ Key (bits 5..6) = IA
+# HEX-NEXT: 0x00030420 03000000 2c000080 78563412 2d000020
+##                     ^^^^^^^^ Addend = 3
+##                              ^^^^ Discr = 44
+##                                    ^^ Key (bits 5..6) = IA
+##                                    ^^ Addr diversity (bit 7) = true
+##                                       ^^^^^^^^ Addend = 0x12345678
+##                                                ^^^^ Discr = 45
+##                                                      ^^ Key (bits 5..6) = DA
+# HEX-NEXT: 0x00030430 00000000 2e000020 00000000 2f000020
+##                     ^^^^^^^^ No implicit addend (rela reloc)
+##                              ^^^^ Discr = 46
+##                                    ^^ Key (bits 5..6) = DA
+##                                       ^^^^^^^^ Addend = 0
+##                                                ^^^^ Discr = 47
+##                                                      ^^ Key (bits 5..6) = DA
+# HEX-NEXT: 0x00030440 00000000 30000000 00000000 00310000
+##                     ^^^^^^^^ Addend = 0
+##                              ^^^^ Discr = 48
+##                                    ^^ Key (bits 5..6) = IA
+##                                         ^^^^^^ ^^ No implicit addend (rela reloc)
+##                                                  ^^^^ Discr = 49
+# HEX-NEXT: 0x00030450 20000500 00003200 0020{{\ }}
+##                     ^^ Key (bits 5..6) = DA
+##                         ^^^^ ^^^^ Addend = 5
+##                                  ^^^^ Discr = 48
+##                                         ^^ Key (bits 5..6) = DA
+
+.section .test, "aw"
+.p2align 3
+.quad (__ehdr_start + 1)@AUTH(da,42)
+.quad (__ehdr_start + 2)@AUTH(ia,43)
+.quad (__ehdr_start + 3)@AUTH(ia,44,addr)
----------------
MaskRay wrote:

Regarding: pack-dyn-relocs.s

> If so, I'll submit a subsequent PR with such changes - please let me know if it's needed.

Sounds good!

https://github.com/llvm/llvm-project/pull/72714