Fixes rust-lang#2715.

Author: Nathan Ringo

bindgen-tests/tests/expectations/tests/noreturn.rs

@@ -2,3 +2,4 @@
 _Noreturn void f(void);
 __attribute__((noreturn)) void g(void);
 [[noreturn]] void h(void);
+void i(__attribute__((noreturn)) void (*arg)(void));

bindgen-tests/tests/headers/noreturn.hpp

@@ -435,8 +435,8 @@ impl FunctionSig {
 
         // Don't parse operatorxx functions in C++
         let is_operator = |spelling: &str| {
-            spelling.starts_with("operator") &&
-                !clang::is_valid_identifier(spelling)
+            spelling.starts_with("operator")
+                && !clang::is_valid_identifier(spelling)
         };
         if is_operator(&spelling) {
             return Err(ParseError::Continue);
@@ -445,8 +445,8 @@ impl FunctionSig {
         // Constructors of non-type template parameter classes for some reason
         // include the template parameter in their name. Just skip them, since
         // we don't handle well non-type template parameters anyway.
-        if (kind == CXCursor_Constructor || kind == CXCursor_Destructor) &&
-            spelling.contains('<')
+        if (kind == CXCursor_Constructor || kind == CXCursor_Destructor)
+            && spelling.contains('<')
         {
             return Err(ParseError::Continue);
         }
@@ -458,11 +458,11 @@ impl FunctionSig {
         };
 
         let mut args = match kind {
-            CXCursor_FunctionDecl |
-            CXCursor_Constructor |
-            CXCursor_CXXMethod |
-            CXCursor_ObjCInstanceMethodDecl |
-            CXCursor_ObjCClassMethodDecl => {
+            CXCursor_FunctionDecl
+            | CXCursor_Constructor
+            | CXCursor_CXXMethod
+            | CXCursor_ObjCInstanceMethodDecl
+            | CXCursor_ObjCClassMethodDecl => {
                 args_from_ty_and_cursor(ty, &cursor, ctx)
             }
             _ => {
@@ -505,16 +505,31 @@ impl FunctionSig {
                 Default::default()
             };
 
-        // This looks easy to break but the clang parser keeps the type spelling clean even if
-        // other attributes are added.
-        is_divergent =
-            is_divergent || ty.spelling().contains("__attribute__((noreturn))");
+        // Check if the type contains __attribute__((noreturn)) outside of parentheses. This is
+        // somewhat fragile, but it seems to be the only way to get at this information as of
+        // libclang 9.
+        let ty_spelling = ty.spelling();
+        let has_attribute_noreturn = ty_spelling
+            .find("__attribute__((noreturn))")
+            .filter(|&i| {
+                let depth = ty_spelling[..i]
+                    .bytes()
+                    .filter_map(|ch| match ch {
+                        b'(' => Some(1),
+                        b')' => Some(-1),
+                        _ => None,
+                    })
+                    .sum::<isize>();
+                depth == 0
+            })
+            .is_some();
+        is_divergent = is_divergent || has_attribute_noreturn;
 
         let is_method = kind == CXCursor_CXXMethod;
         let is_constructor = kind == CXCursor_Constructor;
         let is_destructor = kind == CXCursor_Destructor;
-        if (is_constructor || is_destructor || is_method) &&
-            cursor.lexical_parent() != cursor.semantic_parent()
+        if (is_constructor || is_destructor || is_method)
+            && cursor.lexical_parent() != cursor.semantic_parent()
         {
             // Only parse constructors once.
             return Err(ParseError::Continue);
@@ -555,8 +570,8 @@ impl FunctionSig {
             }
         }
 
-        let ty_ret_type = if kind == CXCursor_ObjCInstanceMethodDecl ||
-            kind == CXCursor_ObjCClassMethodDecl
+        let ty_ret_type = if kind == CXCursor_ObjCInstanceMethodDecl
+            || kind == CXCursor_ObjCClassMethodDecl
         {
             ty.ret_type()
                 .or_else(|| cursor.ret_type())
@@ -734,13 +749,13 @@ impl ClangSubItemParser for Function {
             _ => return Err(ParseError::Continue),
         };
 
-        if cursor.is_inlined_function() ||
-            cursor
+        if cursor.is_inlined_function()
+            || cursor
                 .definition()
                 .map_or(false, |x| x.is_inlined_function())
         {
-            if !context.options().generate_inline_functions &&
-                !context.options().wrap_static_fns
+            if !context.options().generate_inline_functions
+                && !context.options().wrap_static_fns
             {
                 return Err(ParseError::Continue);
             }
@@ -750,9 +765,9 @@ impl ClangSubItemParser for Function {
             }
 
             // We cannot handle `inline` functions that are not `static`.
-            if context.options().wrap_static_fns &&
-                cursor.is_inlined_function() &&
-                matches!(linkage, Linkage::External)
+            if context.options().wrap_static_fns
+                && cursor.is_inlined_function()
+                && matches!(linkage, Linkage::External)
             {
                 return Err(ParseError::Continue);
             }