[PATCH] D77924: ld128 demangle: allow space for 'L' suffix.

[Elliott Hughes via Phabricator via llvm-commits]

enh updated this revision to Diff 273489.
enh added a comment.

Add test.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D77924/new/

https://reviews.llvm.org/D77924

Files:
  libcxxabi/src/demangle/ItaniumDemangle.h
  libcxxabi/test/test_demangle.pass.cpp
  llvm/include/llvm/Demangle/ItaniumDemangle.h


Index: llvm/include/llvm/Demangle/ItaniumDemangle.h
===================================================================
--- llvm/include/llvm/Demangle/ItaniumDemangle.h
+++ llvm/include/llvm/Demangle/ItaniumDemangle.h
@@ -5174,7 +5174,12 @@
 #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";
 };
 
Index: libcxxabi/test/test_demangle.pass.cpp
===================================================================
--- libcxxabi/test/test_demangle.pass.cpp
+++ libcxxabi/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] =
 {
@@ -29822,6 +29824,12 @@
         "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]);
Index: libcxxabi/src/demangle/ItaniumDemangle.h
===================================================================
--- libcxxabi/src/demangle/ItaniumDemangle.h
+++ libcxxabi/src/demangle/ItaniumDemangle.h
@@ -5174,7 +5174,12 @@
 #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";
 };
 


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