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

[Elliott Hughes via Phabricator via libcxx-commits]

enh updated this revision to Diff 270224.
enh added a comment.

Use actual upper bound.


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
  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/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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