[ELF/AArch64] Fix overflow checks for R_AARCH64_{ABS,PREL}{16,32} relocations.

[ikudrin]

Summary

ABI specifies the allowed range for the result of these relocations as 2^(n-1) <= X < 2^n.

In addition, this patch makes tests for these relocations precise.

[ruiu]

ELF/Target.cpp

58–59 ↗

(On Diff #41055)

This comment has been deleted.

58–59 ↗

(On Diff #41055)

By the way, is isInt<N> correct? Isn't that isInt<N-1>?

[ikudrin]

ELF/Target.cpp

58–59 ↗

(On Diff #41055)

That's why I've made "precise" tests. The old lld was not correct in those cases.

The docs say, that, for example, for R_AARCH64_ABS16 the valid range is -2^15 <= X < 2^16.
-2^15 is the minimum valid value for IsInt<16> and 2^16-1 is the maximum for IsUInt<16>.

[ikudrin]

• Rebase to the top.
• Rename checkIsIntOrUInt -> checkIntUInt, update the body.
• Fix tests.

[ruiu]

LGTM

ELF/Target.cpp

60–61 ↗

(On Diff #41105)

Ah, you are right.

[davide]

looks good, thanks for fixing this one.

lld/trunk/ELF/Target.cpp

 
 template <unsigned N> static void checkUInt(uint64_t V, uint32_t Type) {
   if (isUInt<N>(V))
     return;
   StringRef S = getELFRelocationTypeName(Config->EMachine, Type);
   error("Relocation " + S + " out of range");
 }
 
+template <unsigned N> static void checkIntUInt(uint64_t V, uint32_t Type) {
+  if (isInt<N>(V) || isUInt<N>(V))
+    return;
+  StringRef S = getELFRelocationTypeName(Config->EMachine, Type);
+  error("Relocation " + S + " out of range");
+}
+
 template <unsigned N> static void checkAlignment(uint64_t V, uint32_t Type) {
   if ((V & (N - 1)) == 0)
     return;
   StringRef S = getELFRelocationTypeName(Config->EMachine, Type);
   error("Improper alignment for relocation " + S);
 }
 
 namespace {
static uint64_t getAArch64Page(uint64_t Expr) {
   return Expr & (~static_cast<uint64_t>(0xFFF));
 }
 
 void AArch64TargetInfo::relocateOne(uint8_t *Loc, uint8_t *BufEnd,
                                     uint32_t Type, uint64_t P,
                                     uint64_t SA) const {
   switch (Type) {
   case R_AARCH64_ABS16:
-    checkInt<16>(SA, Type);
+    checkIntUInt<16>(SA, Type);
     write16le(Loc, SA);
     break;
   case R_AARCH64_ABS32:
-    checkInt<32>(SA, Type);
+    checkIntUInt<32>(SA, Type);
     write32le(Loc, SA);
     break;
   case R_AARCH64_ABS64:
     // No overflow check needed.
     write64le(Loc, SA);
     break;
   case R_AARCH64_ADD_ABS_LO12_NC:
     // No overflow check needed.
case R_AARCH64_LDST64_ABS_LO12_NC:
     // No overflow check needed.
     or32le(Loc, (SA & 0xFF8) << 7);
     break;
   case R_AARCH64_LDST8_ABS_LO12_NC:
     // No overflow check needed.
     or32le(Loc, (SA & 0xFFF) << 10);
     break;
   case R_AARCH64_PREL16:
-    checkInt<16>(SA - P, Type);
+    checkIntUInt<16>(SA - P, Type);
     write16le(Loc, SA - P);
     break;
   case R_AARCH64_PREL32:
-    checkInt<32>(SA - P, Type);
+    checkIntUInt<32>(SA - P, Type);
     write32le(Loc, SA - P);
     break;
   case R_AARCH64_PREL64:
     // No overflow check needed.
     write64le(Loc, SA - P);
     break;
   default:
     error("unrecognized reloc " + Twine(Type));

lld/trunk/test/ELF/Inputs/abs255.s

+.global foo
+foo = 255

lld/trunk/test/ELF/Inputs/abs256.s

+.global foo
+foo = 256

lld/trunk/test/ELF/Inputs/abs257.s

+.global foo
+foo = 257

lld/trunk/test/ELF/aarch64-abs16-error.s

-// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t
-// RUN: not ld.lld -shared %t -o %t2 2>&1 | FileCheck %s
-// REQUIRES: aarch64
-
-.hword sym+65539
-
-// CHECK: R_AARCH64_ABS16 out of range

lld/trunk/test/ELF/aarch64-abs16.s

+// REQUIRES: aarch64
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs255.s -o %t255.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs256.s -o %t256.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs257.s -o %t257.o
+
+.data
+  .hword foo + 0xfeff
+  .hword foo - 0x8100
+
+// RUN: ld.lld -shared %t.o %t256.o -o %t.so
+// RUN: llvm-objdump -s -section=.data %t.so | FileCheck %s
+
+// CHECK: Contents of section .data:
+// 1090: S = 0x100, A = 0xfeff
+//       S + A = 0xffff
+// 1092: S = 0x100, A = -0x8100
+//       S + A = 0x8000
+// CHECK-NEXT: 1090 ffff0080
+
+// RUN: not ld.lld -shared %t.o %t255.o -o %t.so
+//   | FileCheck %s --check-prefix=OVERFLOW
+// RUN: not ld.lld -shared %t.o %t257.o -o %t.so
+//   | FileCheck %s --check-prefix=OVERFLOW
+// OVERFLOW: Relocation R_AARCH64_ABS16 out of range

lld/trunk/test/ELF/aarch64-abs32-error.s

-// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t
-// RUN: not ld.lld -shared %t -o %t2 2>&1 | FileCheck %s
-// REQUIRES: aarch64
-
-.word sym+99999999999
-
-// CHECK: R_AARCH64_ABS32 out of range

lld/trunk/test/ELF/aarch64-abs32.s

+// REQUIRES: aarch64
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs255.s -o %t255.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs256.s -o %t256.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs257.s -o %t257.o
+
+.data
+  .word foo + 0xfffffeff
+  .word foo - 0x80000100
+
+// RUN: ld.lld -shared %t.o %t256.o -o %t.so
+// RUN: llvm-objdump -s -section=.data %t.so | FileCheck %s
+
+// CHECK: Contents of section .data:
+// 1090: S = 0x100, A = 0xfffffeff
+//       S + A = 0xffffffff
+// 1094: S = 0x100, A = -0x80000100
+//       S + A = 0x80000000
+// CHECK-NEXT: 1090 ffffffff 00000080
+
+// RUN: not ld.lld -shared %t.o %t255.o -o %t.so
+//   | FileCheck %s --check-prefix=OVERFLOW
+// RUN: not ld.lld -shared %t.o %t257.o -o %t.so
+//   | FileCheck %s --check-prefix=OVERFLOW
+// OVERFLOW: Relocation R_AARCH64_ABS32 out of range

lld/trunk/test/ELF/aarch64-data-relocs.s

 // RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t
 // RUN: ld.lld -shared %t -o %t2
-// RUN: llvm-objdump -d %t2 | FileCheck %s
+// RUN: llvm-objdump -s %t2 | FileCheck %s
 // REQUIRES: aarch64
 
-.section .R_AARCH64_ABS16, "ax",@progbits
-  .hword sym+12
-
-.section .R_AARCH64_ABS32, "ax",@progbits
-  .word sym+24
-
 .section .R_AARCH64_ABS64, "ax",@progbits
-  .xword sym+36
+  .xword sym + 36
 
-// CHECK: Disassembly of section .R_AARCH64_ABS16:
-// CHECK-NEXT: $d.0:
-// CHECK-NEXT:     1000:       0c 00   .short
-//                             ^-- A = 0xc
-
-// CHECK-NEXT: Disassembly of section .R_AARCH64_ABS32:
-// CHECK-NEXT: $d.1:
-// CHECK-NEXT:     1002:       18 00 00 00     .word
-//                             ^-- A = 0x18
-
-// CHECK-NEXT: Disassembly of section .R_AARCH64_ABS64:
-// CHECK-NEXT: $d.2:
-// CHECK-NEXT:     1006:       24 00 00 00     .word
-//                             ^-- A = 0x24
-// CHECK-NEXT:     100a:       00 00 00 00     .word
+// CHECK: Contents of section .R_AARCH64_ABS64:
+// CHECK-NEXT: 1000 24000000 00000000
+//                  ^-- A = 0x24
 
-.section .R_AARCH64_PREL16, "ax",@progbits
-  .hword sym - . + 12
-.section .R_AARCH64_PREL32, "ax",@progbits
-  .word sym - . + 24
 .section .R_AARCH64_PREL64, "ax",@progbits
   .xword sym - . + 36
 
-// S + A = 0xc
-// P = 0x100e
-// SA - P = 0xeffe
-// CHECK: Disassembly of section .R_AARCH64_PREL16:
-// CHECK-NEXT: $d.3:
-// CHECK-NEXT:     100e:       fe ef   .short
-
-// S + A = 0x18
-// P = 0x1010
-// SA - P = 0xfffff016
-// CHECK: Disassembly of section .R_AARCH64_PREL32:
-// CHECK-NEXT: $d.4:
-// CHECK-NEXT:     1010:       08 f0 ff ff     .word
-
 // S + A = 0x24
-// P = 0x1014
-// SA - P = 0xfffffffffffff010
-// CHECK: Disassembly of section .R_AARCH64_PREL64:
-// CHECK-NEXT: $d.5:
-// CHECK-NEXT:     1014:       10 f0 ff ff     .word
-// CHECK-NEXT:     1018:       ff ff ff ff     .word
+// P = 0x1008
+// SA - P = 0xfffffffffffff01c
+// CHECK: Contents of section .R_AARCH64_PREL64:
+// CHECK-NEXT: 1008 1cf0ffff ffffffff

lld/trunk/test/ELF/aarch64-prel16-error.s

-// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t
-// RUN: not ld.lld -shared %t -o %t2 2>&1 | FileCheck %s
-// REQUIRES: aarch64
-
-.hword sym + 65539 - .
-
-// CHECK: R_AARCH64_PREL16 out of range

lld/trunk/test/ELF/aarch64-prel16.s

+// REQUIRES: aarch64
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs255.s -o %t255.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs256.s -o %t256.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs257.s -o %t257.o
+
+.data
+  .hword foo - . + 0x10f8f
+  .hword foo - . - 0x706e
+
+// Note: If this test fails, it is probably results from
+//       the change of the address of the .data section.
+//       You may found the correct address in the aarch64_abs16.s test,
+//       if it's already fixed. Then, update addends accordingly.
+// RUN: ld.lld -shared %t.o %t256.o -o %t.so
+// RUN: llvm-objdump -s -section=.data %t.so | FileCheck %s
+
+// CHECK: Contents of section .data:
+// 1090: S = 0x100, A = 0x10f8f, P = 0x1090
+//       S + A - P = 0xffff
+// 1092: S = 0x100, A = -0x706e, P = 0x1092
+//       S + A - P = 0x8000
+// CHECK-NEXT: 1090 ffff0080
+
+// RUN: not ld.lld -shared %t.o %t255.o -o %t.so
+//   | FileCheck %s --check-prefix=OVERFLOW
+// RUN: not ld.lld -shared %t.o %t257.o -o %t.so
+//   | FileCheck %s --check-prefix=OVERFLOW
+// OVERFLOW: Relocation R_AARCH64_PREL16 out of range

lld/trunk/test/ELF/aarch64-prel32-error.s

-// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t
-// RUN: not ld.lld -shared %t -o %t2 2>&1 | FileCheck %s
-// REQUIRES: aarch64
-
-.word sym + 99999999999 - .
-
-// CHECK: R_AARCH64_PREL32 out of range

lld/trunk/test/ELF/aarch64-prel32.s

+// REQUIRES: aarch64
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %s -o %t.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs255.s -o %t255.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs256.s -o %t256.o
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-freebsd %S/Inputs/abs257.s -o %t257.o
+
+.data
+  .word foo - . + 0x100000f8f
+  .word foo - . - 0x7ffff06c
+
+// Note: If this test fails, it is probably results from
+//       the change of the address of the .data section.
+//       You may found the correct address in the aarch64_abs32.s test,
+//       if it's already fixed. Then, update addends accordingly.
+// RUN: ld.lld -shared %t.o %t256.o -o %t.so
+// RUN: llvm-objdump -s -section=.data %t.so | FileCheck %s
+
+// CHECK: Contents of section .data:
+// 1090: S = 0x100, A = 0x100000f8f, P = 0x1090
+//       S + A - P = 0xffffffff
+// 1094: S = 0x100, A = -0x7ffff06c, P = 0x1094
+//       S + A - P = 0x80000000
+// CHECK-NEXT: 1090 ffffffff 00000080
+
+// RUN: not ld.lld -shared %t.o %t255.o -o %t.so
+//   | FileCheck %s --check-prefix=OVERFLOW
+// RUN: not ld.lld -shared %t.o %t257.o -o %t.so
+//   | FileCheck %s --check-prefix=OVERFLOW
+// OVERFLOW: Relocation R_AARCH64_PREL32 out of range