[lld] [lld][AArch64][ELF][PAC] Support `.relr.auth.dyn` section (PR #87635)
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Tue May 14 17:20:07 PDT 2024
================
@@ -38,71 +40,167 @@
# NOPIE-NEXT: 0x2304A0 R_AARCH64_AUTH_ABS64 bar2 0x0
# NOPIE-NEXT: }
-# RUN: ld.lld -pie %t.o %t.a.so -o %t.pie
-# RUN: llvm-readelf -S -d -r -x .test %t.pie | FileCheck --check-prefixes=PIE,HEX %s
-
-# PIE: Section Headers:
-# PIE-NEXT: Name Type Address Off Size ES Flg Lk Inf Al
-# PIE: .rela.dyn RELA {{0*}}[[#%x,ADDR1:]]
-# PIE-SAME: {{0*}}[[#ADDR1]] 000108 18 A 1 0 8
-
-# PIE: Relocation section '.rela.dyn' at offset 0x[[#ADDR1]] contains 11 entries:
-# PIE-NEXT: Offset Info Type Symbol's Value Symbol's Name + Addend
-# PIE-NEXT: 0000000000030470 0000000000000411 R_AARCH64_AUTH_RELATIVE 1
-# PIE-NEXT: 0000000000030478 0000000000000411 R_AARCH64_AUTH_RELATIVE 30472
-# PIE-NEXT: 0000000000030480 0000000000000411 R_AARCH64_AUTH_RELATIVE fffffffffffffffd
-# PIE-NEXT: 0000000000030488 0000000000000411 R_AARCH64_AUTH_RELATIVE 12345678
-# PIE-NEXT: 0000000000030490 0000000000000411 R_AARCH64_AUTH_RELATIVE 123456789a
-# PIE-NEXT: 0000000000030498 0000000000000411 R_AARCH64_AUTH_RELATIVE ffffffedcba98766
-# PIE-NEXT: 00000000000304a0 0000000000000411 R_AARCH64_AUTH_RELATIVE 8003046f
-# PIE-NEXT: 00000000000304b9 0000000000000411 R_AARCH64_AUTH_RELATIVE 4
-# PIE-NEXT: 00000000000304c2 0000000000000411 R_AARCH64_AUTH_RELATIVE 30475
-# PIE-NEXT: 00000000000304a8 0000000100000244 R_AARCH64_AUTH_ABS64 0000000000000000 zed2 + 1111
-# PIE-NEXT: 00000000000304b0 0000000200000244 R_AARCH64_AUTH_ABS64 0000000000000000 bar2 + 0
+# RUN: ld.lld -pie -z pack-relative-relocs main.o a.so -o main.pie
+# RUN: llvm-readelf -S -d -r -x .test main.pie | FileCheck --check-prefixes=RELR,HEX %s
+
+# RELR: Section Headers:
+# RELR-NEXT: Name Type Address Off Size ES Flg Lk Inf Al
+# RELR: .rela.dyn RELA {{0*}}[[ADDR1:.*]] {{0*}}[[ADDR1]] 000090 18 A 1 0 8
+# RELR: .relr.auth.dyn AARCH64_AUTH_RELR {{0*}}[[ADDR2:.*]] {{0*}}[[ADDR2]] 000018 08 A 0 0 8
+
+# RELR: Dynamic section at offset {{.*}} contains 16 entries
+# RELR: 0x0000000070000012 (AARCH64_AUTH_RELR) 0x[[ADDR2]]
+# RELR-NEXT: 0x0000000070000011 (AARCH64_AUTH_RELRSZ) 24 (bytes)
+# RELR-NEXT: 0x0000000070000013 (AARCH64_AUTH_RELRENT) 8 (bytes)
+
+## Decoded SHT_RELR section is same as UNPACKED,
+## but contains only the relative relocations.
+## Any relative relocations with odd offset or value wider than 32 bits stay in SHT_RELA.
+
+# RELR: Relocation section '.rela.dyn' at offset 0x[[ADDR1]] contains 6 entries:
+# RELR-NEXT: Offset Info Type Symbol's Value Symbol's Name + Addend
+# RELR-NEXT: 0000000000030460 0000000000000411 R_AARCH64_AUTH_RELATIVE 123456789a
+# RELR-NEXT: 0000000000030468 0000000000000411 R_AARCH64_AUTH_RELATIVE ffffffedcba98766
+# RELR-NEXT: 0000000000030470 0000000000000411 R_AARCH64_AUTH_RELATIVE 8003043f
+# RELR-NEXT: 0000000000030489 0000000000000411 R_AARCH64_AUTH_RELATIVE 4
+# RELR-NEXT: 0000000000030478 0000000100000244 R_AARCH64_AUTH_ABS64 0000000000000000 zed2 + 1111
+# RELR-NEXT: 0000000000030480 0000000200000244 R_AARCH64_AUTH_ABS64 0000000000000000 bar2 + 0
+# RELR-EMPTY:
+# RELR-NEXT: Relocation section '.relr.auth.dyn' at offset 0x[[ADDR2]] contains 5 entries:
+# RELR-NEXT: Index: Entry Address Symbolic Address
+# RELR-NEXT: 0000: 0000000000030440 0000000000030440 $d.0
+# RELR-NEXT: 0001: 000000000000000f 0000000000030448 $d.0 + 0x8
+# RELR-NEXT: 0000000000030450 $d.0 + 0x10
+# RELR-NEXT: 0000000000030458 $d.0 + 0x18
+# RELR-NEXT: 0002: 0000000000030492 0000000000030492 $d.0 + 0x52
# HEX: Hex dump of section '.test':
-# HEX-NEXT: 0x00030470 00000000 2a000020 00000000 2b000000
+# HEX-NEXT: 0x00030440 01000000 2a000020 42040300 2b000000
+## ^^^^^^^^ Implicit val = 1 = __ehdr_start + 1
## ^^^^ Discr = 42
## ^^ Key (bits 5..6) = DA
+## ^^^^^^^^ Implicit val = 0x30442 = 0x30440 + 2 = .test + 2
## ^^^^ Discr = 43
## ^^ Key (bits 5..6) = IA
-# HEX-NEXT: 0x00030480 00000000 2c000080 00000000 2d000020
+# HEX-NEXT: 0x00030450 fdffffff 2c000080 78563412 2d000020
+## ^^^^^^^^ Implicit val = -3 = __ehdr_start - 3
## ^^^^ Discr = 44
## ^^ Key (bits 5..6) = IA
## ^^ Addr diversity (bit 7) = true
+## ^^^^^^^^ Implicit val = 0x12345678 = __ehdr_start + 0x12345678
## ^^^^ Discr = 45
## ^^ Key (bits 5..6) = DA
-# HEX-NEXT: 0x00030490 00000000 2e000020 00000000 2f000020
+# HEX-NEXT: 0x00030460 00000000 2e000020 00000000 2f000020
+## ^^^^^^^^ No implicit val (rela reloc due val wider than 32 bits)
## ^^^^ Discr = 46
## ^^ Key (bits 5..6) = DA
+## ^^^^^^^^ No implicit val (rela reloc due to val wider than 32 bits)
## ^^^^ Discr = 47
## ^^ Key (bits 5..6) = DA
-# HEX-NEXT: 0x000304a0 00000000 30000020 00000000 31000020
+# HEX-NEXT: 0x00030470 00000000 30000020 00000000 31000020
+## ^^^^^^^^ No implicit val (rela reloc due val wider than 32 bits)
## ^^^^ Discr = 48
## ^^ Key (bits 5..6) = DA
+## ^^^^^^^^ No implicit val (rela reloc due to a preemptible symbol)
## ^^^^ Discr = 49
## ^^ Key (bits 5..6) = DA
-# HEX-NEXT: 0x000304b0 00000000 32000000 77000000 00330000
+# HEX-NEXT: 0x00030480 00000000 32000000 77000000 00330000
+## ^^^^^^^^ No implicit val (rela reloc due to a preemptible symbol)
## ^^^^ Discr = 50
## ^^ Key (bits 5..6) = IA
+## ^^^^^^ ^^ No implicit val (rela reloc due to odd offset)
## ^^^^ Discr = 51
-# HEX-NEXT: 0x000304c0 20770000 00003400 0020{{\ }}
+# HEX-NEXT: 0x00030490 20774504 03003400 0020{{\ }}
## ^^ Key (bits 5..6) = DA
+## ^^^^ ^^^^ Implicit val = 0x30445 = 0x30440 + 5 = .test + 5
## ^^^^ Discr = 52
## ^^ Key (bits 5..6) = DA
+#--- main.s
+
.section .test, "aw"
.p2align 3
.quad (__ehdr_start + 1)@AUTH(da,42)
.quad (.test + 2)@AUTH(ia,43)
.quad (__ehdr_start - 3)@AUTH(ia,44,addr)
.quad (__ehdr_start + 0x12345678)@AUTH(da,45)
+## Addend wider than 32 bits, not enough room for storing implicitly, would go to rela
.quad (__ehdr_start + 0x123456789A)@AUTH(da,46)
+## Negative addend wider than 32 bits, not enough room for storing implicitly, would go to rela
.quad (__ehdr_start - 0x123456789A)@AUTH(da,47)
+## INT32_MAX plus non-zero .test is wider than 32 bits, not enough room for storing implicitly, would go to rela
.quad (.test + 0x7FFFFFFF)@AUTH(da,48)
.quad (zed2 + 0x1111)@AUTH(da,49)
.quad bar2 at AUTH(ia,50)
.byte 0x77
.quad (__ehdr_start + 4)@AUTH(da,51)
.byte 0x77
.quad (.test + 5)@AUTH(da,52)
+
+#--- empty-relr.s
+
+## .relr.auth.dyn relocations that do not fit 32 bits are moved to .rela.dyn.
+## In this case .relr.auth.dyn will be made empty, but
+## removeUnusedSyntheticSections fails to remove the section.
+
+# RUN: llvm-mc -filetype=obj -triple=aarch64 empty-relr.s -o empty-relr.o
+# RUN: ld.lld -pie -z pack-relative-relocs empty-relr.o -o empty-relr
+# RUN: llvm-readelf -S -d -r empty-relr | FileCheck --check-prefixes=EMPTY-RELR %s
+
+# EMPTY-RELR: Section Headers:
+# EMPTY-RELR-NEXT: Name Type Address Off Size ES Flg Lk Inf Al
+# EMPTY-RELR: .rela.dyn RELA {{0*}}[[ADDR1:.*]] {{0*}}[[ADDR1]] 000018 18 A 0 0 8
+# EMPTY-RELR: .relr.auth.dyn AARCH64_AUTH_RELR {{0*}}[[ADDR2:.*]] {{0*}}[[ADDR2]] 000000 08 A 0 0 8
+
+# EMPTY-RELR: Dynamic section at offset {{.*}} contains 12 entries
+# EMPTY-RELR-NOT: (AARCH64_AUTH_RELR)
+# EMPTY-RELR-NOT: (AARCH64_AUTH_RELRSZ)
+# EMPTY-RELR-NOT: (AARCH64_AUTH_RELRENT)
+# EMPTY-RELR: 0x0000000000000007 (RELA) 0x[[ADDR1]]
+# EMPTY-RELR-NEXT: 0x0000000000000008 (RELASZ) 24 (bytes)
+# EMPTY-RELR-NEXT: 0x0000000000000009 (RELAENT) 24 (bytes)
+
+# EMPTY-RELR: Relocation section '.rela.dyn' at offset {{.*}} contains 1 entries:
+# EMPTY-RELR-NEXT: Offset Info Type Symbol's Value Symbol's Name + Addend
+# EMPTY-RELR-NEXT: 0000000000030320 0000000000000411 R_AARCH64_AUTH_RELATIVE 8003031f
+# EMPTY-RELR-EMPTY:
+# EMPTY-RELR-NEXT: Relocation section '.relr.auth.dyn' at offset {{.*}} contains 0 entries:
+# EMPTY-RELR-NEXT: Index: Entry Address Symbolic Address
+
+.section .test, "aw"
+.p2align 3
+.quad (.test + 0x7FFFFFFF)@AUTH(da,42)
+
+#--- empty-rela.s
+
+## .relr.auth.dyn relocations that do not fit 32 bits are moved to .rela.dyn.
+## If this scenario does not happen, .rela.dyn will remain empty,
+## but removeUnusedSyntheticSections fails to remove the section.
+
+# RUN: llvm-mc -filetype=obj -triple=aarch64 empty-rela.s -o empty-rela.o
+# RUN: ld.lld -pie -z pack-relative-relocs empty-rela.o -o empty-rela
+# RUN: llvm-readelf -S -d -r empty-rela | FileCheck --check-prefixes=EMPTY-RELA %s
+
+# EMPTY-RELA: Section Headers:
+# EMPTY-RELA-NEXT: Name Type Address Off Size ES Flg Lk Inf Al
+# EMPTY-RELA: .rela.dyn RELA {{0*}}[[ADDR1:.*]] {{0*}}[[ADDR1]] 000000 18 A 0 0 8
----------------
MaskRay wrote:
`[[#%x,ADDR1]]` and `{{0*}}[[#ADDR1]]` below.
Better to avoid `.*`
https://github.com/llvm/llvm-project/pull/87635
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