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llvm-project/clang/test/CodeGen/PR32874.c

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[ubsan] Skip overflow checks on safe arithmetic (fixes PR32874) Currently, ubsan emits overflow checks for arithmetic that is known to be safe at compile-time, e.g: 1 + 1 => CheckedAdd(1, 1) This leads to breakage when using the __builtin_prefetch intrinsic. LLVM expects the arguments to @llvm.prefetch to be constant integers, and when ubsan inserts unnecessary checks on the operands to the intrinsic, this contract is broken, leading to verifier failures (see PR32874). Instead of special-casing __builtin_prefetch for ubsan, this patch fixes the underlying problem, i.e that clang currently emits unnecessary overflow checks. Testing: I ran the check-clang and check-ubsan targets with a stage2, ubsan-enabled build of clang. I added a regression test for PR32874, and some extra checking to make sure we don't regress runtime checking for unsafe arithmetic. The existing ubsan-promoted-arithmetic.cpp test also provides coverage for this change. llvm-svn: 301988
2017-05-03 07:46:56 +08:00
// RUN: %clang_cc1 -x c -S -emit-llvm -o - -triple x86_64-apple-darwin10 %s \
// RUN: -w -fsanitize=signed-integer-overflow,unsigned-integer-overflow,integer-divide-by-zero,float-divide-by-zero \
// RUN: | FileCheck %s
[test] Add {{.*}} to make tests immune to dso_local/dso_preemptable/(none) differences For a definition (of most linkage types), dso_local is set for ELF -fno-pic/-fpie and COFF, but not for Mach-O. This nuance causes unneeded binary format differences. This patch replaces (function) `define ` with `define{{.*}} `, (variable/constant/alias) `= ` with `={{.*}} `, or inserts appropriate `{{.*}} ` if there is an explicit linkage. * Clang will set dso_local for Mach-O, which is currently implied by TargetMachine.cpp. This will make COFF/Mach-O and executable ELF similar. * Eventually I hope we can make dso_local the textual LLVM IR default (write explicit "dso_preemptable" when applicable) and -fpic ELF will be similar to everything else. This patch helps move toward that goal.
2020-12-31 12:45:56 +08:00
// CHECK-LABEL: define{{.*}} void @foo
[ubsan] Skip overflow checks on safe arithmetic (fixes PR32874) Currently, ubsan emits overflow checks for arithmetic that is known to be safe at compile-time, e.g: 1 + 1 => CheckedAdd(1, 1) This leads to breakage when using the __builtin_prefetch intrinsic. LLVM expects the arguments to @llvm.prefetch to be constant integers, and when ubsan inserts unnecessary checks on the operands to the intrinsic, this contract is broken, leading to verifier failures (see PR32874). Instead of special-casing __builtin_prefetch for ubsan, this patch fixes the underlying problem, i.e that clang currently emits unnecessary overflow checks. Testing: I ran the check-clang and check-ubsan targets with a stage2, ubsan-enabled build of clang. I added a regression test for PR32874, and some extra checking to make sure we don't regress runtime checking for unsafe arithmetic. The existing ubsan-promoted-arithmetic.cpp test also provides coverage for this change. llvm-svn: 301988
2017-05-03 07:46:56 +08:00
// CHECK-NOT: !nosanitize
void foo(const int *p) {
// __builtin_prefetch expects its optional arguments to be constant integers.
// Check that ubsan does not instrument any safe arithmetic performed in
// operands to __builtin_prefetch. (A clang frontend check should reject
// unsafe arithmetic in these operands.)
__builtin_prefetch(p, 0 + 1, 0 + 3);
__builtin_prefetch(p, 1 - 0, 3 - 0);
__builtin_prefetch(p, 1 * 1, 1 * 3);
__builtin_prefetch(p, 1 / 1, 3 / 1);
__builtin_prefetch(p, 3 % 2, 3 % 1);
__builtin_prefetch(p, 0U + 1U, 0U + 3U);
__builtin_prefetch(p, 1U - 0U, 3U - 0U);
__builtin_prefetch(p, 1U * 1U, 1U * 3U);
__builtin_prefetch(p, 1U / 1U, 3U / 1U);
__builtin_prefetch(p, 3U % 2U, 3U % 1U);
}
[test] Add {{.*}} to make tests immune to dso_local/dso_preemptable/(none) differences For a definition (of most linkage types), dso_local is set for ELF -fno-pic/-fpie and COFF, but not for Mach-O. This nuance causes unneeded binary format differences. This patch replaces (function) `define ` with `define{{.*}} `, (variable/constant/alias) `= ` with `={{.*}} `, or inserts appropriate `{{.*}} ` if there is an explicit linkage. * Clang will set dso_local for Mach-O, which is currently implied by TargetMachine.cpp. This will make COFF/Mach-O and executable ELF similar. * Eventually I hope we can make dso_local the textual LLVM IR default (write explicit "dso_preemptable" when applicable) and -fpic ELF will be similar to everything else. This patch helps move toward that goal.
2020-12-31 12:45:56 +08:00
// CHECK-LABEL: define{{.*}} void @ub_constant_arithmetic
A significant number of our tests in C accidentally use functions without prototypes. This patch converts the function signatures to have a prototype for the situations where the test is not specific to K&R C declarations. e.g., void func(); becomes void func(void); This is the ninth batch of tests being updated (there are a significant number of other tests left to be updated).
2022-02-13 21:02:46 +08:00
void ub_constant_arithmetic(void) {
[ubsan] Skip overflow checks on safe arithmetic (fixes PR32874) Currently, ubsan emits overflow checks for arithmetic that is known to be safe at compile-time, e.g: 1 + 1 => CheckedAdd(1, 1) This leads to breakage when using the __builtin_prefetch intrinsic. LLVM expects the arguments to @llvm.prefetch to be constant integers, and when ubsan inserts unnecessary checks on the operands to the intrinsic, this contract is broken, leading to verifier failures (see PR32874). Instead of special-casing __builtin_prefetch for ubsan, this patch fixes the underlying problem, i.e that clang currently emits unnecessary overflow checks. Testing: I ran the check-clang and check-ubsan targets with a stage2, ubsan-enabled build of clang. I added a regression test for PR32874, and some extra checking to make sure we don't regress runtime checking for unsafe arithmetic. The existing ubsan-promoted-arithmetic.cpp test also provides coverage for this change. llvm-svn: 301988
2017-05-03 07:46:56 +08:00
// Check that we still instrument unsafe arithmetic, even if it is known to
// be unsafe at compile time.
int INT_MIN = 0xffffffff;
int INT_MAX = 0x7fffffff;
// CHECK: call void @__ubsan_handle_add_overflow
// CHECK: call void @__ubsan_handle_add_overflow
INT_MAX + 1;
INT_MAX + -1;
// CHECK: call void @__ubsan_handle_negate_overflow
// CHECK: call void @__ubsan_handle_sub_overflow
-INT_MIN;
-INT_MAX - 2;
// CHECK: call void @__ubsan_handle_mul_overflow
// CHECK: call void @__ubsan_handle_mul_overflow
INT_MAX * INT_MAX;
INT_MIN * INT_MIN;
// CHECK: call void @__ubsan_handle_divrem_overflow
// CHECK: call void @__ubsan_handle_divrem_overflow
1 / 0;
INT_MIN / -1;
// CHECK: call void @__ubsan_handle_divrem_overflow
// CHECK: call void @__ubsan_handle_divrem_overflow
1 % 0;
INT_MIN % -1;
// CHECK: call void @__ubsan_handle_divrem_overflow
1.0 / 0.0;
}