Index: clang-tidy/misc/CMakeLists.txt
===================================================================
--- clang-tidy/misc/CMakeLists.txt
+++ clang-tidy/misc/CMakeLists.txt
@@ -23,6 +23,7 @@
SizeofContainerCheck.cpp
StaticAssertCheck.cpp
StringIntegerAssignmentCheck.cpp
+ SuspiciousMissingCommaCheck.cpp
SuspiciousSemicolonCheck.cpp
SwappedArgumentsCheck.cpp
ThrowByValueCatchByReferenceCheck.cpp
Index: clang-tidy/misc/MiscTidyModule.cpp
===================================================================
--- clang-tidy/misc/MiscTidyModule.cpp
+++ clang-tidy/misc/MiscTidyModule.cpp
@@ -31,6 +31,7 @@
#include "SizeofContainerCheck.h"
#include "StaticAssertCheck.h"
#include "StringIntegerAssignmentCheck.h"
+#include "SuspiciousMissingCommaCheck.h"
#include "SuspiciousSemicolonCheck.h"
#include "SwappedArgumentsCheck.h"
#include "ThrowByValueCatchByReferenceCheck.h"
@@ -88,6 +89,8 @@
"misc-static-assert");
CheckFactories.registerCheck<StringIntegerAssignmentCheck>(
"misc-string-integer-assignment");
+ CheckFactories.registerCheck<SuspiciousMissingCommaCheck>(
+ "misc-suspicious-missing-comma");
CheckFactories.registerCheck<SuspiciousSemicolonCheck>(
"misc-suspicious-semicolon");
CheckFactories.registerCheck<SwappedArgumentsCheck>(
Index: clang-tidy/misc/SuspiciousMissingCommaCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/misc/SuspiciousMissingCommaCheck.h
@@ -0,0 +1,41 @@
+//===--- SuspiciousMissingCommaCheck.h - clang-tidy--------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_SUSPICIOUS_MISSING_COMMA_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_SUSPICIOUS_MISSING_COMMA_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+/// This check finds string literals which are probably concatenated accidentally.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/misc-suspicious-missing-comma.html
+class SuspiciousMissingCommaCheck : public ClangTidyCheck {
+public:
+ SuspiciousMissingCommaCheck(StringRef Name, ClangTidyContext *Context);
+ void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+ // Minimal size of a string literals array to be considered by the checker.
+ const unsigned SizeThreshold;
+ // Maximal threshold ratio of suspicious string literals to be considered.
+ const double RatioThreshold;
+};
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_SUSPICIOUS_MISSING_COMMA_H
Index: clang-tidy/misc/SuspiciousMissingCommaCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/misc/SuspiciousMissingCommaCheck.cpp
@@ -0,0 +1,80 @@
+//===--- SuspiciousMissingCommaCheck.cpp - clang-tidy----------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SuspiciousMissingCommaCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+namespace {
+
+AST_MATCHER(StringLiteral, isConcatenatedLiteral) {
+ return Node.getNumConcatenated() > 1;
+}
+
+} // namespace
+
+SuspiciousMissingCommaCheck::SuspiciousMissingCommaCheck(
+ StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context),
+ SizeThreshold(Options.get("SizeThreshold", 5U)),
+ RatioThreshold(std::stod(Options.get("RatioThreshold", ".2"))) {}
+
+void SuspiciousMissingCommaCheck::storeOptions(
+ ClangTidyOptions::OptionMap &Opts) {
+ Options.store(Opts, "SizeThreshold", SizeThreshold);
+ Options.store(Opts, "RatioThreshold", std::to_string(RatioThreshold));
+}
+
+void SuspiciousMissingCommaCheck::registerMatchers(MatchFinder *Finder) {
+ const auto ConcatenatedStringLiteral =
+ stringLiteral(isConcatenatedLiteral()).bind("str");
+
+ const auto StringsInitializerList =
+ initListExpr(hasType(constantArrayType()),
+ has(expr(ignoringImpCasts(ConcatenatedStringLiteral))));
+
+ Finder->addMatcher(StringsInitializerList.bind("list"), this);
+}
+
+void SuspiciousMissingCommaCheck::check(
+ const MatchFinder::MatchResult &Result) {
+ const auto *InitializerList = Result.Nodes.getNodeAs<InitListExpr>("list");
+ const auto *ConcatenatedLiteral = Result.Nodes.getNodeAs<Expr>("str");
+ assert(InitializerList && ConcatenatedLiteral);
+
+ // Skip small arrays as they often generate false-positive.
+ unsigned int Size = InitializerList->getNumInits();
+ if (Size < SizeThreshold) return;
+
+ // Count the number of occurence of concatenated string literal.
+ unsigned int Count = 0;
+ for (unsigned int i = 0; i < Size; ++i) {
+ const Expr *Child = InitializerList->getInit(i)->IgnoreImpCasts();
+ if (const auto *Literal = dyn_cast<StringLiteral>(Child)) {
+ if (Literal->getNumConcatenated() > 1) ++Count;
+ }
+ }
+
+ // Warn only when concatenation is not common in this initializer list.
+ // The current threshold is set to less than 1/5 of the string literals.
+ if (double(Count) / Size > RatioThreshold) return;
+
+ diag(ConcatenatedLiteral->getLocStart(),
+ "suspicious string literal, probably missing a comma");
+}
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -66,6 +66,7 @@
misc-sizeof-container
misc-static-assert
misc-string-integer-assignment
+ misc-suspicious-missing-comma
misc-suspicious-semicolon
misc-swapped-arguments
misc-throw-by-value-catch-by-reference
Index: docs/clang-tidy/checks/misc-suspicious-missing-comma.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/misc-suspicious-missing-comma.rst
@@ -0,0 +1,35 @@
+.. title:: clang-tidy - misc-suspicious-missing-comma
+
+misc-suspicious-missing-comma
+=============================
+
+String literals placed side-by-side are concatenated at translation phase 6
+(after the preprocessor). This feature is used to represent long string
+literal on multiple lines.
+
+For instance, these declarations are equivalent:
+ const char* A[] = "This is a test";
+ const char* B[] = "This" " is a "
+ "test";
+
+A common mistake done by programmers is to forget a comma between two string
+literals in an array initializer list.
+
+ const char* Test[] = {
+ "line 1",
+ "line 2" // Missing comma!
+ "line 3",
+ "line 4",
+ "line 5"
+ };
+
+The array contains the string "line 2line3" at offset 1 (i.e. Test[1]). Clang
+won't generate warnings at compile time.
+
+This checker may warn incorrectly on cases like:
+
+ const char* SupportedFormat[] = {
+ "Error %s",
+ "Code " PRIu64, // May warn here.
+ "Warning %s",
+ };
Index: test/clang-tidy/misc-suspicious-missing-comma.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/misc-suspicious-missing-comma.cpp
@@ -0,0 +1,34 @@
+// RUN: %check_clang_tidy %s misc-suspicious-missing-comma %t
+
+const char* Cartoons[] = {
+ "Bugs Bunny",
+ "Homer Simpson",
+ "Mickey Mouse",
+ "Bart Simpson",
+ "Charlie Brown" // There is a missing comma here.
+ "Fred Flintstone",
+ "Popeye",
+};
+// CHECK-MESSAGES: :[[@LINE-4]]:3: warning: suspicious string literal, probably missing a comma [misc-suspicious-missing-comma]
+
+const wchar_t* Colors[] = {
+ L"Red", L"Yellow", L"Blue", L"Green", L"Purple", L"Rose", L"White", L"Black"
+};
+
+// The following array should not trigger any warnings.
+const char* HttpCommands[] = {
+ "GET / HTTP/1.0\r\n"
+ "\r\n",
+
+ "GET /index.html HTTP/1.0\r\n"
+ "\r\n",
+
+ "GET /favicon.ico HTTP/1.0\r\n"
+ "header: dummy"
+ "\r\n",
+};
+
+// This array is too small to trigger a warning.
+const char* SmallArray[] = {
+ "a" "b", "c"
+};