ld128 demangle: allow space for 'L' suffix.
Summary:
Caught by HWASAN on arm64 Android (which uses ld128 for long double). This
was running the existing fuzzer.
The specific minimized fuzz input to reproduce this is:
__cxa_demangle("1\006ILeeeEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE", 0, 0, 0);
Reviewers: eugenis, srhines, #libc_abi!
Subscribers: kristof.beyls, danielkiss, libcxx-commits
Tags: #libc_abi
Differential Revision: https://reviews.llvm.org/D77924
GitOrigin-RevId: a7d0b7a786c769440143acb94f533149faac12c9
diff --git a/src/demangle/ItaniumDemangle.h b/src/demangle/ItaniumDemangle.h
index 6ab8732..ede9c6d 100644
--- a/src/demangle/ItaniumDemangle.h
+++ b/src/demangle/ItaniumDemangle.h
@@ -5203,7 +5203,12 @@
#else
static const size_t mangled_size = 20; // May need to be adjusted to 16 or 24 on other platforms
#endif
- static const size_t max_demangled_size = 40;
+ // `-0x1.ffffffffffffffffffffffffffffp+16383` + 'L' + '\0' == 42 bytes.
+ // 28 'f's * 4 bits == 112 bits, which is the number of mantissa bits.
+ // Negatives are one character longer than positives.
+ // `0x1.` and `p` are constant, and exponents `+16383` and `-16382` are the
+ // same length. 1 sign bit, 112 mantissa bits, and 15 exponent bits == 128.
+ static const size_t max_demangled_size = 42;
static constexpr const char *spec = "%LaL";
};
diff --git a/test/test_demangle.pass.cpp b/test/test_demangle.pass.cpp
index ef75b61..236c1d9 100644
--- a/test/test_demangle.pass.cpp
+++ b/test/test_demangle.pass.cpp
@@ -15,6 +15,8 @@
// Is long double fp80? (Only x87 extended double has 64-bit mantissa)
#define LDBL_FP80 (__LDBL_MANT_DIG__ == 64)
+// Is long double fp128?
+#define LDBL_FP128 (__LDBL_MANT_DIG__ == 113)
const char* cases[][2] =
{
@@ -29837,6 +29839,11 @@
"void test0::h<float>(char (&) [(unsigned int)((sizeof (float)) + (0xap-1L))])",
}},
#endif
+#if LDBL_FP128
+ // This was found by libFuzzer+HWASan on aarch64 Android.
+ {"1\006ILeeeEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE",
+ {"\x6<-0x1.cecececececececececececececep+11983"}},
+#endif
};
const unsigned NF = sizeof(fp_literal_cases) / sizeof(fp_literal_cases[0]);
const unsigned NEF = sizeof(fp_literal_cases[0].expecting) / sizeof(fp_literal_cases[0].expecting[0]);
