[ELF][PPC][X86] Use [-2**(n-1), 2**n) to check overflows for R_PPC_ADDR16, R_PPC64_ADDR{16,32}, R_X86_64_{8,16}

[MaskRay]

Summary

Similar to R_AARCH64_ABS32, R_PPC64_ADDR32 can represent either a signed
value or unsigned value, thus we should use [-2**(n-1), 2**n) instead of
[-2**(n-1), 2**(n-1)) to check overflows.

The issue manifests as a bogus linker error when linking the powerpc64le Linux kernel.
The new behavior is compatible with ld.bfd's complain_overflow_bitfield.

The upper bound of the error message is not correct. Fix it as well.

The changes to R_PPC_ADDR16, R_PPC64_ADDR16, R_X86_64_8 and R_X86_64_16 are similar.

[MaskRay]

Add `` to fix markdown code blocks

[MaskRay]

Fix R_X86_64_{8,16} as well

[MaskRay]

ELF/Arch/X86_64.cpp

368 ↗

(On Diff #206133)

This is special, bfd uses complain_overflow_unsigned for this, so this does not need a fix..

[ruiu]

LGTM

[MaskRay]

use .code16 to make i386 tests more reasonable

ELF/Arch/PPC.cpp

static std::pair<RelType, uint64_t> fromDTPREL(RelType Type, uint64_t Val) {
   }
 }
 
 void PPC::relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const {
   RelType NewType;
   std::tie(NewType, Val) = fromDTPREL(Type, Val);
   switch (NewType) {
   case R_PPC_ADDR16:
+    checkIntUInt(Loc, Val, 16, Type);
+    write16(Loc, Val);
+    break;
   case R_PPC_GOT16:
   case R_PPC_GOT_TLSGD16:
   case R_PPC_GOT_TLSLD16:
   case R_PPC_GOT_TPREL16:
   case R_PPC_TPREL16:
     checkInt(Loc, Val, 16, Type);
     write16(Loc, Val);
     break;

ELF/Arch/PPC64.cpp

void PPC64::relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const {
   case R_PPC64_ADDR14: {
     checkAlignment(Loc, Val, 4, Type);
     // Preserve the AA/LK bits in the branch instruction
     uint8_t AALK = Loc[3];
     write16(Loc + 2, (AALK & 3) | (Val & 0xfffc));
     break;
   }
   case R_PPC64_ADDR16:
-  case R_PPC64_TPREL16:
-    checkInt(Loc, Val, 16, OriginalType);
+    checkIntUInt(Loc, Val, 16, OriginalType);
     write16(Loc, Val);
     break;
+  case R_PPC64_ADDR32:
+    checkIntUInt(Loc, Val, 32, OriginalType);
+    write32(Loc, Val);
+    break;
   case R_PPC64_ADDR16_DS:
   case R_PPC64_TPREL16_DS: {
     checkInt(Loc, Val, 16, OriginalType);
     // DQ-form instructions use bits 28-31 as part of the instruction encoding
     // DS-form instructions only use bits 30-31.
     uint16_t Mask = isDQFormInstruction(readFromHalf16(Loc)) ? 0xf : 0x3;
     checkAlignment(Loc, lo(Val), Mask + 1, OriginalType);
     write16(Loc, (read16(Loc) & Mask) | lo(Val));
if (Config->TocOptimize && ShouldTocOptimize && ha(Val) == 0) {
               "Can't toc-optimize an update instruction: 0x" +
               Twine::utohexstr(Insn));
       Insn &= 0xffe00000 | Mask;
       writeFromHalf16(Loc, Insn | 0x00020000 | lo(Val));
     } else {
       write16(Loc, (read16(Loc) & Mask) | lo(Val));
     }
   } break;
-  case R_PPC64_ADDR32:
+  case R_PPC64_TPREL16:
+    checkInt(Loc, Val, 16, OriginalType);
+    write16(Loc, Val);
+    break;
   case R_PPC64_REL32:
     checkInt(Loc, Val, 32, Type);
     write32(Loc, Val);
     break;
   case R_PPC64_ADDR64:
   case R_PPC64_REL64:
   case R_PPC64_TOC:
     write64(Loc, Val);

ELF/Target.h

 }
 
 // Make sure that V can be represented as an N bit signed or unsigned integer.
 inline void checkIntUInt(uint8_t *Loc, uint64_t V, int N, RelType Type) {
   // For the error message we should cast V to a signed integer so that error
   // messages show a small negative value rather than an extremely large one
   if (V != (uint64_t)llvm::SignExtend64(V, N) && (V >> N) != 0)
     reportRangeError(Loc, Type, Twine((int64_t)V), llvm::minIntN(N),
-                     llvm::maxIntN(N));
+                     llvm::maxUIntN(N));
 }
 
 inline void checkAlignment(uint8_t *Loc, uint64_t V, int N, RelType Type) {
   if ((V & (N - 1)) != 0)
     error(getErrorLocation(Loc) + "improper alignment for relocation " +
           lld::toString(Type) + ": 0x" + llvm::utohexstr(V) +
           " is not aligned to " + Twine(N) + " bytes");
 }

test/ELF/aarch64-abs16.s

 
 // CHECK: Contents of section .data:
 // 210000: S = 0x100, A = 0xfeff
 //         S + A = 0xffff
 // 210002: S = 0x100, A = -0x8100
 //         S + A = 0x8000
 // CHECK-NEXT: 210000 ffff0080
 
-// RUN: not ld.lld %t.o %t255.o -o %t2 2>&1 | FileCheck %s --check-prefix=OVERFLOW1
-// OVERFLOW1: relocation R_AARCH64_ABS16 out of range: -32769 is not in [-32768, 32767]
+// RUN: not ld.lld %t.o %t255.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=OVERFLOW1
+// OVERFLOW1: relocation R_AARCH64_ABS16 out of range: -32769 is not in [-32768, 65535]
 
-// RUN: not ld.lld %t.o %t257.o -o %t2 2>&1 | FileCheck %s --check-prefix=OVERFLOW2
-// OVERFLOW2: relocation R_AARCH64_ABS16 out of range: 65536 is not in [-32768, 32767]
+// RUN: not ld.lld %t.o %t257.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=OVERFLOW2
+// OVERFLOW2: relocation R_AARCH64_ABS16 out of range: 65536 is not in [-32768, 65535]

test/ELF/aarch64-abs32.s

 
 // CHECK: Contents of section .data:
 // 210000: S = 0x100, A = 0xfffffeff
 //         S + A = 0xffffffff
 // 210004: S = 0x100, A = -0x80000100
 //         S + A = 0x80000000
 // CHECK-NEXT: 210000 ffffffff 00000080
 
-// RUN: not ld.lld %t.o %t255.o -o %t2 2>&1 | FileCheck %s --check-prefix=OVERFLOW1
-// OVERFLOW1: relocation R_AARCH64_ABS32 out of range: -2147483649 is not in [-2147483648, 2147483647]
+// RUN: not ld.lld %t.o %t255.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=OVERFLOW1
+// OVERFLOW1: relocation R_AARCH64_ABS32 out of range: -2147483649 is not in [-2147483648, 4294967295]
 
-// RUN: not ld.lld %t.o %t257.o -o %t2 2>&1 | FileCheck %s --check-prefix=OVERFLOW2
-// OVERFLOW2: relocation R_AARCH64_ABS32 out of range: 4294967296 is not in [-2147483648, 2147483647]
+// RUN: not ld.lld %t.o %t257.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=OVERFLOW2
+// OVERFLOW2: relocation R_AARCH64_ABS32 out of range: 4294967296 is not in [-2147483648, 4294967295]

test/ELF/aarch64-prel16.s

 // CHECK: Contents of section .data:
 // 201000: S = 0x100, A = 0x210eff, P = 0x201000
 //         S + A - P = 0xffff
 // 201002: S = 0x100, A = 0x1f8f02, P = 0x201002
 //         S + A - P = 0x8000
 // CHECK-NEXT: 201000 ffff0080
 
 // RUN: not ld.lld -z max-page-size=4096 %t.o %t255.o -o %t2 2>&1 | FileCheck %s --check-prefix=OVERFLOW1
-// OVERFLOW1: relocation R_AARCH64_PREL16 out of range: -32769 is not in [-32768, 32767]
+// OVERFLOW1: relocation R_AARCH64_PREL16 out of range: -32769 is not in [-32768, 65535]
 
 // RUN: not ld.lld -z max-page-size=4096 %t.o %t257.o -o %t2 2>&1 | FileCheck %s --check-prefix=OVERFLOW2
-// OVERFLOW2: relocation R_AARCH64_PREL16 out of range: 65536 is not in [-32768, 32767]
+// OVERFLOW2: relocation R_AARCH64_PREL16 out of range: 65536 is not in [-32768, 65535]

test/ELF/aarch64-prel32.s

 // CHECK: Contents of section .data:
 // 201000: S = 0x100, A = 0x100200eff, P = 0x201000
 //         S + A - P = 0xffffffff
 // 201004: S = 0x100, A = -0x7fdff0fc, P = 0x201004
 //         S + A - P = 0x80000000
 // CHECK-NEXT: 201000 ffffffff 00000080
 
 // RUN: not ld.lld -z max-page-size=4096 %t.o %t255.o -o %t2 2>&1 | FileCheck %s --check-prefix=OVERFLOW1
-// OVERFLOW1: relocation R_AARCH64_PREL32 out of range: -2147483649 is not in [-2147483648, 2147483647]
+// OVERFLOW1: relocation R_AARCH64_PREL32 out of range: -2147483649 is not in [-2147483648, 4294967295]
 
 // RUN: not ld.lld -z max-page-size=4096 %t.o %t257.o -o %t2 2>&1 | FileCheck %s --check-prefix=OVERFLOW2
-// OVERFLOW2: relocation R_AARCH64_PREL32 out of range: 4294967296 is not in [-2147483648, 2147483647]
+// OVERFLOW2: relocation R_AARCH64_PREL32 out of range: 4294967296 is not in [-2147483648, 4294967295]

test/ELF/i386-reloc-16.s

 // REQUIRES: x86
 
 // RUN: llvm-mc -filetype=obj -triple=i386-pc-linux %S/Inputs/x86-64-reloc-16.s -o %t1
 // RUN: llvm-mc -filetype=obj -triple=i386-pc-linux %S/Inputs/x86-64-reloc-16-error.s -o %t2
 // RUN: llvm-mc -filetype=obj -triple=i386-pc-linux %s -o %t
 // RUN: ld.lld -shared %t %t1 -o %t3
 // RUN: llvm-objdump -s %t3 | FileCheck %s
 
 // CHECK:      Contents of section .text:
 // CHECK-NEXT:   1000 42
 
 // RUN: not ld.lld -shared %t %t2 -o /dev/null 2>&1 | FileCheck --check-prefix=ERROR %s
-// ERROR: relocation R_386_16 out of range: 65536 is not in [-32768, 32767]
+// ERROR: relocation R_386_16 out of range: 65536 is not in [-32768, 65535]
 
 .short foo

test/ELF/i386-reloc-8.s

 // REQUIRES: x86
 
 // RUN: llvm-mc -filetype=obj -triple=i386-pc-linux %S/Inputs/i386-reloc-8.s -o %t1
 // RUN: llvm-mc -filetype=obj -triple=i386-pc-linux %S/Inputs/i386-reloc-8-error.s -o %t2
 // RUN: llvm-mc -filetype=obj -triple=i386-pc-linux %s -o %t
 // RUN: ld.lld -shared %t %t1 -o %t3
 // RUN: llvm-objdump -s %t3 | FileCheck %s
 
 // CHECK:      Contents of section .text:
 // CHECK-NEXT:   1000 ff
 
 // RUN: not ld.lld -shared %t %t2 -o /dev/null 2>&1 | FileCheck --check-prefix=ERROR %s
-// ERROR: relocation R_386_8 out of range: 256 is not in [-128, 127]
+// ERROR: relocation R_386_8 out of range: 256 is not in [-128, 255]
 
 .byte foo

test/ELF/ppc32-reloc-addr.s

 # REQUIRES: ppc
 # RUN: llvm-mc -filetype=obj -triple=powerpc %s -o %t.o
-# RUN: ld.lld --noinhibit-exec %t.o --defsym=a=0x1234 --defsym=b=0xbcdef -o %t 2>&1 | \
-# RUN:   FileCheck --check-prefix=WARN %s
+# RUN: ld.lld %t.o --defsym=a=0x1234 --defsym=b=0xbcdef -o %t
 # RUN: llvm-objdump -d --no-show-raw-insn %t | FileCheck %s
 # RUN: llvm-objdump -s --no-show-raw-insn %t | FileCheck --check-prefix=HEX %s
 
-.section .R_PPC_ADDR16,"ax",@progbits
-  lis 4, a
-  lis 4, b
-# CHECK-LABEL: section .R_PPC_ADDR16:
-# CHECK: lis 4, 4660
-# WARN: warning: {{.*}}.o:(.R_PPC_ADDR16+0x6): relocation R_PPC_ADDR16 out of range: 773615 is not in [-32768, 32767]
-
 .section .R_PPC_ADDR16_HA,"ax",@progbits
   lis 4, a@ha
 # CHECK-LABEL: section .R_PPC_ADDR16_HA:
 # CHECK: lis 4, 0
 
 .section .R_PPC_ADDR16_HI,"ax",@progbits
   lis 4, a@h
 # CHECK-LABEL: section .R_PPC_ADDR16_HI:

test/ELF/ppc64-addr16-error.s

-// REQUIRES: ppc
-
-// RUN: llvm-mc -filetype=obj -triple=powerpc64le-unknown-linux %s -o %t
-// RUN: llvm-mc -filetype=obj -triple=powerpc64le-unknown-linux %p/Inputs/ppc64-addr16-error.s -o %t2
-// RUN: not ld.lld -shared %t %t2 -o /dev/null 2>&1 | FileCheck %s
-
-// RUN: llvm-mc -filetype=obj -triple=powerpc64-unknown-linux %s -o %t
-// RUN: llvm-mc -filetype=obj -triple=powerpc64-unknown-linux %p/Inputs/ppc64-addr16-error.s -o %t2
-// RUN: not ld.lld -shared %t %t2 -o /dev/null 2>&1 | FileCheck %s
-
-.short sym+65539
-
-// CHECK: relocation R_PPC64_ADDR16 out of range: 65539 is not in [-32768, 32767]

test/ELF/ppc64-reloc-addr.s

+# REQUIRES: ppc
+# RUN: llvm-mc -filetype=obj -triple=powerpc64le %s -o %t.o
+# RUN: llvm-mc -filetype=obj -triple=powerpc64le %S/Inputs/abs255.s -o %t255.o
+# RUN: llvm-mc -filetype=obj -triple=powerpc64le %S/Inputs/abs256.s -o %t256.o
+# RUN: llvm-mc -filetype=obj -triple=powerpc64le %S/Inputs/abs257.s -o %t257.o
+
+# RUN: ld.lld %t.o %t256.o -o %t
+# RUN: llvm-readelf -x .data %t | FileCheck %s
+# CHECK: 0x{{[0-9a-f]+}} ffff0080 ffffffff 00000080
+
+# RUN: not ld.lld %t.o %t255.o -o /dev/null 2>&1 | FileCheck --check-prefix=OVERFLOW1 %s
+# OVERFLOW1: relocation R_PPC64_ADDR16 out of range: -32769 is not in [-32768, 65535]
+# OVERFLOW1: relocation R_PPC64_ADDR32 out of range: -2147483649 is not in [-2147483648, 4294967295]
+
+# RUN: not ld.lld %t.o %t257.o -o /dev/null 2>&1 | FileCheck --check-prefix=OVERFLOW2 %s
+# OVERFLOW2: relocation R_PPC64_ADDR16 out of range: 65536 is not in [-32768, 65535]
+# OVERFLOW2: relocation R_PPC64_ADDR32 out of range: 4294967296 is not in [-2147483648, 4294967295]
+
+.globl _start
+_start:
+.data
+.word foo + 0xfeff
+.word foo - 0x8100
+.long foo + 0xfffffeff
+.long foo - 0x80000100