[clang-tools-extra] [clang-tidy] Add new performance-use-starts-ends-with check (PR #72385)

[Piotr Zegar via cfe-commits]

================
@@ -0,0 +1,151 @@
+// RUN: %check_clang_tidy -std=c++20 %s performance-use-starts-ends-with %t -- \
+// RUN:   -- -isystem %clang_tidy_headers
+
+#include <string>
+
+std::string foo(std::string);
+std::string bar();
+
+#define A_MACRO(x, y) ((x) == (y))
+#define STR(x) std::string(x)
+
+class sub_string : public std::string {};
+class sub_sub_string : public sub_string {};
+
+struct string_like {
+  bool starts_with(const char *s) const;
+  size_t find(const char *s, size_t pos = 0) const;
+};
+
+struct string_like_camel {
+  bool startsWith(const char *s) const;
+  size_t find(const char *s, size_t pos = 0) const;
+};
+
+struct prefer_underscore_version {
+  bool starts_with(const char *s) const;
+  bool startsWith(const char *s) const;
+  size_t find(const char *s, size_t pos = 0) const;
+};
+
+struct prefer_underscore_version_flip {
+  bool startsWith(const char *s) const;
+  bool starts_with(const char *s) const;
+  size_t find(const char *s, size_t pos = 0) const;
+};
+
+struct prefer_underscore_version_inherit : public string_like {
+  bool startsWith(const char *s) const;
+};
+
+void test(std::string s, std::string_view sv, sub_string ss, sub_sub_string sss,
+          string_like sl, string_like_camel slc, prefer_underscore_version puv,
+          prefer_underscore_version_flip puvf,
+          prefer_underscore_version_inherit puvi) {
+  s.find("a") == 0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with instead of find() == 0
+  // CHECK-FIXES: s.starts_with("a");
+
+  s.find(s) == 0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: s.starts_with(s);
+
+  s.find("aaa") != 0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: !s.starts_with("aaa");
+
+  s.find(foo(foo(bar()))) != 0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: !s.starts_with(foo(foo(bar())));
+
+  if (s.find("....") == 0) { /* do something */ }
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: if (s.starts_with("...."))
+
+  0 != s.find("a");
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: !s.starts_with("a");
+
+  s.rfind("a", 0) == 0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with instead of rfind() == 0
+  // CHECK-FIXES: s.starts_with("a");
+
+  s.rfind(s, 0) == 0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: s.starts_with(s);
+
+  s.rfind("aaa", 0) != 0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: !s.starts_with("aaa");
+
+  s.rfind(foo(foo(bar())), 0) != 0;
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: !s.starts_with(foo(foo(bar())));
+
+  if (s.rfind("....", 0) == 0) { /* do something */ }
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: if (s.starts_with("...."))
+
+  0 != s.rfind("a", 0);
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: !s.starts_with("a");
+
+  0 == STR(s).find("a");
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
+  // CHECK-FIXES: STR(s).starts_with("a");
+
+  #define STR str
+  std::string STR;
+  if (0 == STR.find("ala")) { /* do something */}
----------------
PiotrZSL wrote:

Add few more test withs macros:
- method name under macro
- argument under macro
- 0 under macro
- operator under macro  - #define EQ(x,y) (x) == (y)


https://github.com/llvm/llvm-project/pull/72385