[PATCH] D46293: [clang-tidy/google-runtime-int] Allow passing non-bitwidth types to printf()-style APIs

[Ben Hamilton via Phabricator via cfe-commits]

benhamilton created this revision.
benhamilton added reviewers: alexfh, bkramer.
Herald added subscribers: cfe-commits, klimek.

The `google-runtime-int` check currently fires on calls like:

  printf("%lu", (unsigned long)foo);

However, the style guide says:

> Where possible, avoid passing arguments of types specified by
>  bitwidth typedefs to printf-based APIs.

http://google.github.io/styleguide/cppguide.html#64-bit_Portability

This diff relaxes the check to not fire on parameters to functions
with the `__format__` attribute. (I didn't specifically check
for `__printf__` since there are a few variations.)

Test Plan: New tests added. Ran tests with:

  % make -j16 check-clang-tools


Repository:
  rCTE Clang Tools Extra

https://reviews.llvm.org/D46293

Files:
  clang-tidy/google/IntegerTypesCheck.cpp
  test/clang-tidy/google-runtime-int.cpp


Index: test/clang-tidy/google-runtime-int.cpp
===================================================================
--- test/clang-tidy/google-runtime-int.cpp
+++ test/clang-tidy/google-runtime-int.cpp
@@ -72,3 +72,11 @@
   B a, b;
   a = b;
 }
+
+__attribute__((__format__ (__printf__, 1, 2)))
+void myprintf(const char* s, ...);
+
+void doprint() {
+  uint64 foo = 23;
+  myprintf("foo %lu %lu", (unsigned long)42, (unsigned long)foo);
+}
Index: clang-tidy/google/IntegerTypesCheck.cpp
===================================================================
--- clang-tidy/google/IntegerTypesCheck.cpp
+++ clang-tidy/google/IntegerTypesCheck.cpp
@@ -11,6 +11,7 @@
 #include "clang/AST/ASTContext.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/Basic/AttrKinds.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/TargetInfo.h"
@@ -56,7 +57,16 @@
   // Find all TypeLocs. The relevant Style Guide rule only applies to C++.
   if (!getLangOpts().CPlusPlus)
     return;
-  Finder->addMatcher(typeLoc(loc(isInteger())).bind("tl"), this);
+  // Match any integer types, unless they are passed to a printf-based API:
+  //
+  // http://google.github.io/styleguide/cppguide.html#64-bit_Portability
+  // "Where possible, avoid passing arguments of types specified by
+  // bitwidth typedefs to printf-based APIs."
+  Finder->addMatcher(typeLoc(loc(isInteger()),
+                             unless(hasAncestor(callExpr(
+                                 callee(functionDecl(hasAttr(attr::Format)))))))
+                         .bind("tl"),
+                     this);
   IdentTable = llvm::make_unique<IdentifierTable>(getLangOpts());
 }
 


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