[clang] [clang] Avoid printing overly large integer/_BitInt numbers in static assertion failure diagnostics #71675 (PR #145053)

[Erich Keane via cfe-commits]

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@@ -17575,7 +17576,21 @@ static bool ConvertAPValueToString(const APValue &V, QualType T,
           break;
         }
       }
-      V.getInt().toString(Str);
+
+      llvm::APSInt vInt = V.getInt();
+      if (llvm::APSInt::compareValues(
+              vInt, llvm::APSInt::getUnsigned(
+                        std::numeric_limits<uint64_t>::max())) >= 0 ||
+          vInt < std::numeric_limits<int64_t>::min()) {
+        // The value of cutSize is not special, it is just a number of
+        // characters that gives us enough info without losing readability
+        const int cutSize = 20;
+        vInt.toString(Str, 16);
+        Str.erase(Str.begin() + cutSize, Str.end() - cutSize);
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erichkeane wrote:

>we can get the number of remaing using value.logBase2/log2(Radix) +1 that actually gives the exact count.

That sounds VAGUELY familiar :)  Its been a few decades since I've been in a math class....

With the 'pow', you probably need SOME sort of guard to make sure you don't exceed the number we can store.

https://github.com/llvm/llvm-project/pull/145053