[clang-format] Add better support for co-routinues

Responding to a Discord call to help {D113977} and heavily inspired by the unlanded {D34225} add some support to help coroutinues from not being formatted from

```for co_await(auto elt : seq)```

to

```
for
co_await(auto elt : seq)
```

Because of the dominance of clang-format in the C++ community, I don't think we should make it the blocker that prevents users from embracing the newer parts of the standard because we butcher the layout of some of the new constucts.

Reviewed By: HazardyKnusperkeks, Quuxplusone, ChuanqiXu

Differential Revision: https://reviews.llvm.org/D114859

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 20e99fbf2e136e4046f1d39abaa3345302a29890..149d0e169389f3414acdad6af36de652b8791724 100644 (file)
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -265,7 +265,7 @@ clang-format
   space before parentheses. The custom options can be set using
   ``SpaceBeforeParensOptions``.
 
-- Improved Cpp20 Modules support.
+- Improved C++20 Modules and Coroutines support.
 
 libclang
 --------

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 22faf54b017dac716cd1b27e26c3a4c01b283a0a..a94d8cdc3b0414bb35d8aa2dcfd53f242c28bfa0 100644 (file)
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1004,6 +1004,8 @@ private:
         if (CurrentToken && CurrentToken->is(Keywords.kw_await))
           next();
       }
+      if (Style.isCpp() && CurrentToken && CurrentToken->is(tok::kw_co_await))
+        next();
       Contexts.back().ColonIsForRangeExpr = true;
       next();
       if (!parseParens())
@@ -2952,6 +2954,14 @@ bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
   if (Left.is(tok::kw_auto) && Right.isOneOf(tok::l_paren, tok::l_brace))
     return false;
 
+  // operator co_await(x)
+  if (Right.is(tok::l_paren) && Left.is(tok::kw_co_await) && Left.Previous &&
+      Left.Previous->is(tok::kw_operator))
+    return false;
+  // co_await (x), co_yield (x), co_return (x)
+  if (Left.isOneOf(tok::kw_co_await, tok::kw_co_yield, tok::kw_co_return) &&
+      Right.isNot(tok::semi))
+    return true;
   // requires clause Concept1<T> && Concept2<T>
   if (Left.is(TT_ConstraintJunctions) && Right.is(tok::identifier))
     return true;

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index a7e0422e3146c7a957800b85910cf4399413272c..5b9fe267aae6053f9633dc51c9ce319d5fdd67cc 100644 (file)
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -2399,6 +2399,8 @@ void UnwrappedLineParser::parseForOrWhileLoop() {
   if (Style.Language == FormatStyle::LK_JavaScript &&
       FormatTok->is(Keywords.kw_await))
     nextToken();
+  if (Style.isCpp() && FormatTok->is(tok::kw_co_await))
+    nextToken();
   if (FormatTok->Tok.is(tok::l_paren))
     parseParens();
   if (FormatTok->Tok.is(tok::l_brace)) {

diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 9b6607b46d93a06e8e16bb86cd98f8bfd66f7670..bda5f7019416e287f3032b2f1e3a80d35621e30d 100644 (file)
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -22724,6 +22724,65 @@ TEST_F(FormatTest, Cpp20ModulesSupport) {
   verifyFormat("export", Style);
 }
 
+TEST_F(FormatTest, CoroutineForCoawait) {
+  FormatStyle Style = getLLVMStyle();
+  verifyFormat("for co_await (auto x : range())\n  ;");
+  verifyFormat("for (auto i : arr) {\n"
+               "}",
+               Style);
+  verifyFormat("for co_await (auto i : arr) {\n"
+               "}",
+               Style);
+  verifyFormat("for co_await (auto i : foo(T{})) {\n"
+               "}",
+               Style);
+}
+
+TEST_F(FormatTest, CoroutineCoAwait) {
+  verifyFormat("int x = co_await foo();");
+  verifyFormat("int x = (co_await foo());");
+  verifyFormat("co_await (42);");
+  verifyFormat("void operator co_await(int);");
+  verifyFormat("void operator co_await(a);");
+  verifyFormat("co_await a;");
+  verifyFormat("co_await missing_await_resume{};");
+  verifyFormat("co_await a; // comment");
+  verifyFormat("void test0() { co_await a; }");
+  verifyFormat("co_await co_await co_await foo();");
+  verifyFormat("co_await foo().bar();");
+  verifyFormat("co_await [this]() -> Task { co_return x; }");
+  verifyFormat("co_await [this](int a, int b) -> Task { co_return co_await "
+               "foo(); }(x, y);");
+
+  FormatStyle Style = getLLVMStyle();
+  Style.ColumnLimit = 40;
+  verifyFormat("co_await [this](int a, int b) -> Task {\n"
+               "  co_return co_await foo();\n"
+               "}(x, y);",
+               Style);
+  verifyFormat("co_await;");
+}
+
+TEST_F(FormatTest, CoroutineCoYield) {
+  verifyFormat("int x = co_yield foo();");
+  verifyFormat("int x = (co_yield foo());");
+  verifyFormat("co_yield (42);");
+  verifyFormat("co_yield {42};");
+  verifyFormat("co_yield 42;");
+  verifyFormat("co_yield n++;");
+  verifyFormat("co_yield ++n;");
+  verifyFormat("co_yield;");
+}
+
+TEST_F(FormatTest, CoroutineCoReturn) {
+  verifyFormat("co_return (42);");
+  verifyFormat("co_return;");
+  verifyFormat("co_return {};");
+  verifyFormat("co_return x;");
+  verifyFormat("co_return co_await foo();");
+  verifyFormat("co_return co_yield foo();");
+}
+
 } // namespace
 } // namespace format
 } // namespace clang