[clang-tidy] Avoid checking magic numbers if _BitInt

[vabridgers]

Recent changes to add _BitInt support have caused our internal random testing to fail. This change just avoids a readability magic numbers check for now if a _BitInt. The crash seen (edited for clarity) is shown below.

/llvm/include/llvm/ADT/APInt.h:1488:
uint64_t llvm::APInt::getZExtValue() const: Assertion `getActiveBits()
<= 64 && "Too many bits for uint64_t"' failed.

...
#9

llvm::APInt::getZExtValue() const
/llvm/include/llvm/ADT/APInt.h:1488:5
clang::IntegerLiteral const*) const
/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp:198:47
clang::IntegerLiteral(clang::ast_matchers::MatchFinder::MatchResult
const&, char const*)
/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.h:67:5
clang::ast_matchers::MatchFinder::MatchResult const&)
/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp:152:35
...

Reviewed By: donat.nagy

[llvmbot]

@llvm/pr-subscribers-clang-tidy

Changes

Recent changes to add _BitInt support have caused our internal random testing to fail. This change just avoids a readability magic numbers check for now if a _BitInt. The crash seen (edited for clarity) is shown below.

/llvm/include/llvm/ADT/APInt.h:1488:
uint64_t llvm::APInt::getZExtValue() const: Assertion `getActiveBits()
<= 64 && "Too many bits for uint64_t"' failed.

...
#9

llvm::APInt::getZExtValue() const
/llvm/include/llvm/ADT/APInt.h:1488:5
clang::IntegerLiteral const*) const
/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp:198:47
clang::IntegerLiteral(clang::ast_matchers::MatchFinder::MatchResult
const&, char const*)
/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.h:67:5
clang::ast_matchers::MatchFinder::MatchResult const&)
/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp:152:35
...

Reviewed By: donat.nagy

Full diff: https://github.com/llvm/llvm-project/pull/65888.diff

2 Files Affected:

• (modified) clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp (+3)
• (added) clang-tools-extra/test/clang-tidy/checkers/readability/bitint-no-crash.c (+6)

diff --git a/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp b/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp
index 7f3c2cb9a0434cc..97c20cf200fa21c 100644
--- a/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/MagicNumbersCheck.cpp
@@ -191,6 +191,9 @@ bool MagicNumbersCheck::isConstant(const MatchFinder::MatchResult &Result,
 }
 
 bool MagicNumbersCheck::isIgnoredValue(const IntegerLiteral *Literal) const {
+  if (Literal->getType()->isBitIntType()) {
+    return true;
+  }
   const llvm::APInt IntValue = Literal->getValue();
   const int64_t Value = IntValue.getZExtValue();
   if (Value == 0)
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/bitint-no-crash.c b/clang-tools-extra/test/clang-tidy/checkers/readability/bitint-no-crash.c
new file mode 100644
index 000000000000000..f8660924cbef5a0
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/bitint-no-crash.c
@@ -0,0 +1,6 @@
+// RUN: %check_clang_tidy %s readability-magic-numbers %t --
+
+// Don't crash
+
+_BitInt(128) A = 4533629751480627964421wb;
+// CHECK-MESSAGES: warning

[PiotrZSL]

LGTM,
not perfect, as we going to ignore big ints, but still better than crashing for now.

[NagyDonat]

LGTM as a temporary measure. Perhaps add a TODO note which asks for a more through solution; but you can also merge this as it is now.