6be0b9a8dd
When building abseil-cpp `bin/absl_hash_test` with Clang in -fno-pic
mode, an instruction like `movl $foo-2147483648, $eax` may be produced
(subtracting a number from the address of a static variable). If foo's
address is smaller than 2147483648, GNU ld/gold/LLD will error because
R_X86_64_32 cannot represent a negative value.
```
using absl::Hash;
struct NoOp {
template < typename HashCode >
friend HashCode AbslHashValue(HashCode , NoOp );
};
template <typename> class HashIntTest : public testing::Test {};
TYPED_TEST_SUITE_P(HashIntTest);
TYPED_TEST_P(HashIntTest, BasicUsage) {
if (std::numeric_limits< TypeParam >::min )
EXPECT_NE(Hash< NoOp >()({}),
Hash< TypeParam >()(std::numeric_limits< TypeParam >::min()));
}
REGISTER_TYPED_TEST_CASE_P(HashIntTest, BasicUsage);
using IntTypes = testing::Types< int32_t>;
INSTANTIATE_TYPED_TEST_CASE_P(My, HashIntTest, IntTypes);
ld: error: hash_test.cc:(function (anonymous namespace)::gtest_suite_HashIntTest_::BasicUsage<int>::TestBody(): .text+0x4E472): relocation R_X86_64_32 out of range: 18446744071564237392 is not in [0, 4294967295]; references absl::hash_internal::HashState::kSeed
```
Actually any negative offset is not allowed because the symbol address
can be zero (e.g. set by `-Wl,--defsym=foo=0`). So disallow such folding.
Reviewed By: pengfei
Differential Revision: https://reviews.llvm.org/D93931
110 lines
3.8 KiB
LLVM
110 lines
3.8 KiB
LLVM
; RUN: llc -mtriple=x86_64 -relocation-model=static < %s | FileCheck --check-prefixes=CHECK,STATIC %s
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; RUN: llc -mtriple=x86_64 -relocation-model=pic < %s | FileCheck --check-prefixes=CHECK,PIC %s
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; RUN: llc -mtriple=x86_64 -code-model=medium -relocation-model=static < %s | FileCheck --check-prefixes=CHECK,MSTATIC %s
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; RUN: llc -mtriple=x86_64 -code-model=medium -relocation-model=pic < %s | FileCheck --check-prefixes=CHECK,MPIC %s
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@foo = internal global i32 0
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define dso_local i64 @zero() #0 {
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; CHECK-LABEL: zero:
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; CHECK: # %bb.0:
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; STATIC-NEXT: movl $foo, %eax
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; STATIC-NEXT: retq
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; PIC-NEXT: leaq foo(%rip), %rax
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; PIC-NEXT: retq
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; MSTATIC-NEXT: movabsq $foo, %rax
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; MSTATIC-NEXT: retq
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; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rcx
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; MPIC-NEXT: movabsq $foo@GOTOFF, %rax
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; MPIC-NEXT: addq %rcx, %rax
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entry:
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ret i64 add (i64 ptrtoint (i32* @foo to i64), i64 0)
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}
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define dso_local i64 @one() #0 {
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; CHECK-LABEL: one:
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; CHECK: # %bb.0:
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; STATIC-NEXT: movl $foo+1, %eax
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; PIC-NEXT: leaq foo+1(%rip), %rax
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; MSTATIC-NEXT: movabsq $foo, %rax
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; MSTATIC-NEXT: incq %rax
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; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
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; MPIC-NEXT: movabsq $foo@GOTOFF, %rcx
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; MPIC-NEXT: leaq 1(%rax,%rcx), %rax
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entry:
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ret i64 add (i64 ptrtoint (i32* @foo to i64), i64 1)
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}
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;; Check we don't fold a large offset into leaq, otherwise
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;; the large r_addend can easily cause a relocation overflow.
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define dso_local i64 @large() #0 {
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; CHECK-LABEL: large:
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; CHECK: # %bb.0:
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; STATIC-NEXT: movl $1701208431, %eax
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; STATIC-NEXT: leaq foo(%rax), %rax
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; PIC-NEXT: leaq foo(%rip), %rax
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; PIC-NEXT: addq $1701208431, %rax
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; MSTATIC-NEXT: movabsq $foo, %rax
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; MSTATIC-NEXT: addq $1701208431, %rax
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; MSTATIC-NEXT: retq
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; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
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; MPIC-NEXT: movabsq $foo@GOTOFF, %rcx
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; MPIC-NEXT: leaq 1701208431(%rax,%rcx), %rax
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entry:
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ret i64 add (i64 ptrtoint (i32* @foo to i64), i64 1701208431)
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}
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;; Test we don't emit movl foo-1, %eax. ELF R_X86_64_32 does not allow
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;; a negative value.
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define dso_local i64 @neg_1() #0 {
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; CHECK-LABEL: neg_1:
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; CHECK: # %bb.0:
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; STATIC-NEXT: leaq foo-1(%rip), %rax
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; PIC-NEXT: leaq foo-1(%rip), %rax
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; MSTATIC-NEXT: movabsq $foo, %rax
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; MSTATIC-NEXT: decq %rax
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; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
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; MPIC-NEXT: movabsq $foo@GOTOFF, %rcx
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; MPIC-NEXT: leaq -1(%rax,%rcx), %rax
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entry:
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ret i64 add (i64 ptrtoint (i32* @foo to i64), i64 -1)
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}
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;; Test we don't emit movl foo-2147483648, %eax. ELF R_X86_64_32 does not allow
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;; a negative value.
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define dso_local i64 @neg_0x80000000() #0 {
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; CHECK-LABEL: neg_0x80000000:
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; CHECK: # %bb.0:
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; STATIC-NEXT: leaq foo-2147483648(%rip), %rax
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; PIC-NEXT: leaq foo-2147483648(%rip), %rax
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; MSTATIC-NEXT: movabsq $foo, %rax
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; MSTATIC-NEXT: addq $-2147483648, %rax
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; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
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; MPIC-NEXT: movabsq $foo@GOTOFF, %rcx
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; MPIC-NEXT: leaq -2147483648(%rax,%rcx), %rax
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entry:
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ret i64 add (i64 ptrtoint (i32* @foo to i64), i64 -2147483648)
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}
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define dso_local i64 @neg_0x80000001() #0 {
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; CHECK-LABEL: neg_0x80000001:
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; CHECK: # %bb.0:
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; STATIC-NEXT: movabsq $-2147483649, %rax
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; STATIC-NEXT: leaq foo(%rax), %rax
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; PIC-NEXT: leaq foo(%rip), %rcx
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; PIC-NEXT: movabsq $-2147483649, %rax
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; PIC-NEXT: addq %rcx, %rax
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; MSTATIC-NEXT: movabsq $-2147483649, %rcx
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; MSTATIC-NEXT: movabsq $foo, %rax
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; MSTATIC-NEXT: addq %rcx, %rax
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; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
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; MPIC-NEXT: movabsq $foo@GOTOFF, %rcx
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; MPIC-NEXT: addq %rax, %rcx
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; MPIC-NEXT: movabsq $-2147483649, %rax
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; MPIC-NEXT: addq %rcx, %rax
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entry:
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ret i64 add (i64 ptrtoint (i32* @foo to i64), i64 -2147483649)
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}
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attributes #0 = { nounwind }
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