[clang] 57b95ae - [clang-format] Add better support for co-routinues

[via cfe-commits]

Author: mydeveloperday
Date: 2021-12-02T08:06:43Z
New Revision: 57b95aed2a04f00dc84c4c4926c506528081196d

URL: https://github.com/llvm/llvm-project/commit/57b95aed2a04f00dc84c4c4926c506528081196d
DIFF: https://github.com/llvm/llvm-project/commit/57b95aed2a04f00dc84c4c4926c506528081196d.diff

LOG: [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

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/lib/Format/TokenAnnotator.cpp
    clang/lib/Format/UnwrappedLineParser.cpp
    clang/unittests/Format/FormatTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 20e99fbf2e136..149d0e169389f 100644
--- 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 22faf54b017da..a94d8cdc3b041 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1004,6 +1004,8 @@ class AnnotatingParser {
         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 a7e0422e3146c..5b9fe267aae60 100644
--- 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 9b6607b46d93a..bda5f7019416e 100644
--- 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