[X86] Don't fold negative offset into 32-bit absolute address (e.g. movl $foo-1, %eax)
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