[clang] [clang-format] Fix a bug in `DerivePointerAlignment: true` (PR #150744)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-format

Author: Owen Pan (owenca)

<details>
<summary>Changes</summary>

This effectively reverts a4d4859dc70c046ad928805ddeaf8fa101793394 which didn't fix the problem that `int*,` was not counted as "Left" alignment.

Fixes #<!-- -->150327

---
Full diff: https://github.com/llvm/llvm-project/pull/150744.diff


2 Files Affected:

- (modified) clang/lib/Format/Format.cpp (+11-20) 
- (modified) clang/unittests/Format/FormatTest.cpp (+6-1) 


``````````diff
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 1cfa3d1535902..01d2b4dfc76cc 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -2641,28 +2641,19 @@ class Formatter : public TokenAnalyzer {
     int AlignmentDiff = 0;
     for (const AnnotatedLine *Line : Lines) {
       AlignmentDiff += countVariableAlignments(Line->Children);
-      for (FormatToken *Tok = Line->First; Tok && Tok->Next; Tok = Tok->Next) {
+      const auto *Prev = Line->getFirstNonComment();
+      if (!Prev)
+        break;
+      for (const auto *Tok = Prev->Next; Tok; Prev = Tok, Tok = Tok->Next) {
         if (Tok->isNot(TT_PointerOrReference))
           continue;
-        // Don't treat space in `void foo() &&` or `void() &&` as evidence.
-        if (const auto *Prev = Tok->getPreviousNonComment()) {
-          if (Prev->is(tok::r_paren) && Prev->MatchingParen) {
-            if (const auto *Func =
-                    Prev->MatchingParen->getPreviousNonComment()) {
-              if (Func->isOneOf(TT_FunctionDeclarationName, TT_StartOfName,
-                                TT_OverloadedOperator) ||
-                  Func->isTypeName(LangOpts)) {
-                continue;
-              }
-            }
-          }
-        }
-        bool SpaceBefore = Tok->hasWhitespaceBefore();
-        bool SpaceAfter = Tok->Next->hasWhitespaceBefore();
-        if (SpaceBefore && !SpaceAfter)
-          ++AlignmentDiff;
-        if (!SpaceBefore && SpaceAfter)
-          --AlignmentDiff;
+        const auto *Next = Tok->Next;
+        if (!Next)
+          break;
+        if (Prev->Tok.getIdentifierInfo())
+          AlignmentDiff += Tok->hasWhitespaceBefore() ? 1 : -1;
+        if (Next->Tok.getIdentifierInfo())
+          AlignmentDiff += Next->hasWhitespaceBefore() ? -1 : 1;
       }
     }
     return AlignmentDiff;
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index c20d099cac017..55360965d7575 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -12114,7 +12114,12 @@ TEST_F(FormatTest, UnderstandsFunctionRefQualification) {
            "void b() const &;\n";
   verifyFormat(Prefix + "int *x;", Prefix + "int* x;", DerivePointerAlignment);
 
-  verifyGoogleFormat("MACRO(int*, std::function<void() &&>);");
+  constexpr StringRef Code("MACRO(int*, std::function<void() &&>);");
+  verifyFormat(Code, DerivePointerAlignment);
+
+  auto Style = getGoogleStyle();
+  Style.DerivePointerAlignment = true;
+  verifyFormat(Code, Style);
 }
 
 TEST_F(FormatTest, PointerAlignmentFallback) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/150744