[clang] [clang] Implement lifetime analysis for lifetime_capture_by(X) (PR #115921)

[Haojian Wu via cfe-commits]

================
@@ -793,3 +806,202 @@ void test13() {
 }
 
 } // namespace GH100526
+
+namespace lifetime_capture_by {
+struct X {
+  const int *x;
+  void captureInt(const int& x [[clang::lifetime_capture_by(this)]]) { this->x = &x; }
+  void captureSV(std::string_view sv [[clang::lifetime_capture_by(this)]]);
+};
+///////////////////////////
+// Detect dangling cases.
+///////////////////////////
+void captureInt(const int& i [[clang::lifetime_capture_by(x)]], X& x);
+void captureRValInt(int&& i [[clang::lifetime_capture_by(x)]], X& x);
+void noCaptureInt(int i [[clang::lifetime_capture_by(x)]], X& x);
+
+std::string_view substr(const std::string& s [[clang::lifetimebound]]);
+std::string_view strcopy(const std::string& s);
+
+void captureSV(std::string_view s [[clang::lifetime_capture_by(x)]], X& x);
+void captureRValSV(std::string_view&& sv [[clang::lifetime_capture_by(x)]], X& x);
+void noCaptureSV(std::string_view sv, X& x);
+void captureS(const std::string& s [[clang::lifetime_capture_by(x)]], X& x);
+void captureRValS(std::string&& s [[clang::lifetime_capture_by(x)]], X& x);
+
+const std::string& getLB(const std::string& s[[clang::lifetimebound]]);
+const std::string& getLB(std::string_view sv[[clang::lifetimebound]]);
+const std::string* getPointerLB(const std::string& s[[clang::lifetimebound]]);
+const std::string* getPointerNoLB(const std::string& s);
+
+void capturePointer(const std::string* sp [[clang::lifetime_capture_by(x)]], X& x);
+
+struct ThisIsCaptured {
+  void capture(X& x) [[clang::lifetime_capture_by(x)]];
+  void bar(X& x) [[clang::lifetime_capture_by(abcd)]]; // expected-error {{'lifetime_capture_by' attribute argument 'abcd' is not a known function parameter}}
----------------
hokein wrote:

I think this test and below have been covered in your previous attribute-syntax patch, if so, we can remove them.

https://github.com/llvm/llvm-project/pull/115921