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Revert "[libc] Refactor BigInt" (#87612)

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Reverts llvm/llvm-project#86137

Some aarch64 compilers seem to consider that `uint128_t` is not
`is_trivially_constructible` which prevents `bit_cast`-ing.
This commit is contained in:
Guillaume Chatelet
2024-04-04 11:10:30 +02:00
committed by GitHub
parent 47e996d89d
commit 12735916bd
13 changed files with 781 additions and 1030 deletions
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1
libc/fuzzing/CMakeLists.txt
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@@ -1,7 +1,6 @@
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=fuzzer")
add_custom_target(libc-fuzzer)
add_subdirectory(__support)
# TODO(#85680): Re-enable math fuzzing after headers are sorted out
# add_subdirectory(math)
add_subdirectory(stdlib)

7
libc/fuzzing/__support/CMakeLists.txt
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@@ -1,7 +0,0 @@
add_libc_fuzzer(
uint_fuzz
SRCS
uint_fuzz.cpp
DEPENDS
libc.src.__support.uint
)

70
libc/fuzzing/__support/uint_fuzz.cpp
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@@ -1,70 +0,0 @@
#include "src/__support/CPP/bit.h"
#include "src/__support/UInt.h"
#include "src/string/memory_utils/inline_memcpy.h"
using namespace LIBC_NAMESPACE;
// Helper function when using gdb / lldb to set a breakpoint and inspect values.
template <typename T> void debug_and_trap(const char *msg, T a, T b) {
__builtin_trap();
}
#define DEBUG_AND_TRAP()
#define TEST_BINOP(OP) \
if ((a OP b) != (static_cast<T>(BigInt(a) OP BigInt(b)))) \
debug_and_trap(#OP, a, b);
#define TEST_SHIFTOP(OP) \
if ((a OP b) != (static_cast<T>(BigInt(a) OP b))) \
debug_and_trap(#OP, a, b);
#define TEST_FUNCTION(FUN) \
if (FUN(a) != FUN(BigInt(a))) \
debug_and_trap(#FUN, a, b);
// Test that basic arithmetic operations of BigInt behave like their scalar
// counterparts.
template <typename T, typename BigInt> void run_tests(T a, T b) {
TEST_BINOP(+)
TEST_BINOP(-)
TEST_BINOP(*)
if (b != 0)
TEST_BINOP(/)
if (b >= 0 && b < cpp::numeric_limits<T>::digits) {
TEST_SHIFTOP(<<)
TEST_SHIFTOP(>>)
}
if constexpr (!BigInt::SIGNED) {
TEST_FUNCTION(cpp::has_single_bit)
TEST_FUNCTION(cpp::countr_zero)
TEST_FUNCTION(cpp::countl_zero)
TEST_FUNCTION(cpp::countl_one)
TEST_FUNCTION(cpp::countr_one)
}
}
// Reads a T from libfuzzer data.
template <typename T> T read(const uint8_t *data, size_t &remainder) {
T out = 0;
constexpr size_t T_SIZE = sizeof(T);
const size_t copy_size = remainder < T_SIZE ? remainder : T_SIZE;
inline_memcpy(&out, data, copy_size);
remainder -= copy_size;
return out;
}
template <typename T, typename BigInt>
void run_tests(const uint8_t *data, size_t size) {
const auto a = read<T>(data, size);
const auto b = read<T>(data, size);
run_tests<T, BigInt>(a, b);
}
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
// unsigned
run_tests<uint64_t, BigInt<64, false, uint16_t>>(data, size);
// signed
run_tests<int64_t, BigInt<64, true, uint16_t>>(data, size);
return 0;
}