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Fix a bug in R_X86_64_PC{8,16} relocation handling. 

R_X86_64_PC{8,16} relocations are sign-extended, so when we check
for relocation overflow, we had to use checkInt instead of checkUInt.
I confirmed that GNU linkers create the same output for the test case.

llvm-svn: 353437
This commit is contained in:
Rui Ueyama 2019-02-07 18:12:57 +00:00
parent 93fdec739b
commit 04cbd988f9
3 changed files with 22 additions and 6 deletions
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10
lld/ELF/Arch/X86_64.cpp
View File

@ -324,15 +324,21 @@ template <class ELFT>
void X86_64<ELFT>::relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const { void X86_64<ELFT>::relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const {
switch (Type) { switch (Type) {
case R_X86_64_8: case R_X86_64_8:
case R_X86_64_PC8:
checkUInt(Loc, Val, 8, Type); checkUInt(Loc, Val, 8, Type);
*Loc = Val; *Loc = Val;
break; break;
case R_X86_64_PC8:
checkInt(Loc, Val, 8, Type);
*Loc = Val;
break;
case R_X86_64_16: case R_X86_64_16:
case R_X86_64_PC16:
checkUInt(Loc, Val, 16, Type); checkUInt(Loc, Val, 16, Type);
write16le(Loc, Val); write16le(Loc, Val);
break; break;
case R_X86_64_PC16:
checkInt(Loc, Val, 16, Type);
write16le(Loc, Val);
break;
case R_X86_64_32: case R_X86_64_32:
checkUInt(Loc, Val, 32, Type); checkUInt(Loc, Val, 32, Type);
write32le(Loc, Val); write32le(Loc, Val);

8
lld/test/ELF/Inputs/x86-64-pcrel.s Normal file
View File

@ -0,0 +1,8 @@
.globl foo
foo:
.word _start - foo
.fill 14,1,0xcc
.byte _start - foo
.fill 15,1,0xcc

10
lld/test/ELF/x86-64-pcrel.s
View File

@ -3,13 +3,15 @@
// This is a test for R_X86_64_PC8 and R_X86_64_PC16. // This is a test for R_X86_64_PC8 and R_X86_64_PC16.
// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t1.o // RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t1.o
// RUN: echo '.globl foo; foo:' | llvm-mc -filetype=obj -triple=x86_64-pc-linux - -o %t2.o // RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/x86-64-pcrel.s -o %t2.o
// RUN: ld.lld -o %t.exe %t1.o %t2.o // RUN: ld.lld -o %t.exe %t1.o %t2.o
// RUN: llvm-objdump -s %t.exe | FileCheck %s // RUN: llvm-objdump -s %t.exe | FileCheck %s
// CHECK: Contents of section .text: // CHECK: Contents of section .text:
// CHECK: 2000cccc cccccccc cccccccc cccccccc // CHECK-NEXT: 2000cccc cccccccc cccccccc cccccccc
// CHECK: 20cccccc cccccccc cccccccc cccccccc // CHECK-NEXT: 20cccccc cccccccc cccccccc cccccccc
// CHECK-NEXT: e0ffcccc cccccccc cccccccc cccccccc
// CHECK-NEXT: e0cccccc cccccccc cccccccc cccccccc
.globl _start .globl _start
_start: _start: