[clang-format] Fix a bug in annotating * in #defines

[owenca]

Fixes #99271.

[llvmbot]

@llvm/pr-subscribers-clang-format

Author: Owen Pan (owenca)

Changes

Fixes #99271.

---

Full diff: https://github.com/llvm/llvm-project/pull/99433.diff

2 Files Affected:

• (modified) clang/lib/Format/TokenAnnotator.cpp (+2-1)
• (modified) clang/unittests/Format/TokenAnnotatorTest.cpp (+4)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index b6d6e52ccb8f8..f1125fd35b427 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -374,7 +374,8 @@ class AnnotatingParser {
       Contexts.back().IsExpression = true;
     } else if (Line.InPPDirective &&
                (!OpeningParen.Previous ||
-                OpeningParen.Previous->isNot(tok::identifier))) {
+                OpeningParen.Previous->isNot(tok::identifier) ||
+                !OpeningParen.Previous->Previous)) {
       Contexts.back().IsExpression = true;
     } else if (Contexts[Contexts.size() - 2].CaretFound) {
       // This is the parameter list of an ObjC block.
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index c5e8aa72cd2cb..82c9be0f4df71 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -75,6 +75,10 @@ TEST_F(TokenAnnotatorTest, UnderstandsUsesOfStarAndAmp) {
   EXPECT_TOKEN(Tokens[10], tok::r_paren, TT_TypeDeclarationParen);
   EXPECT_TOKEN(Tokens[11], tok::star, TT_PointerOrReference);
 
+  Tokens = annotate("#define FOO bar(a * b)");
+  ASSERT_EQ(Tokens.size(), 10u) << Tokens;
+  EXPECT_TOKEN(Tokens[6], tok::star, TT_BinaryOperator);
+
   Tokens = annotate("void f() {\n"
                     "  while (p < a && *p == 'a')\n"
                     "    p++;\n"

[hnakamura5]

This change certainly fixes the issue, but also seems specific for the reported code.
For example it does not work well for the case the line contains something else as,

#define FN(N) void fn(void *addr) { a + f(addr, 0, N * two); }

This results the annotations where * is PointerOrReference,

{(hash, "#" , Unknown), (identifier, "define" , Unknown), (identifier, "FN" , Unknown), (l_paren, "(" , Unknown),
(identifier, "N" , Unknown), (r_paren, ")" , Unknown), (void, "void" , Unknown), (identifier, "fn" , FunctionDeclarationName), 
(l_paren, "(" , FunctionDeclarationLParen), (void, "void" , Unknown), (star, "*" , PointerOrReference),
(identifier, "addr" , StartOfName), (r_paren, ")" , Unknown), (l_brace, "{" , FunctionLBrace)👈, (identifier, "a" , Unknown),
(plus, "+" , BinaryOperator), (identifier, "f" , Unknown), (l_paren, "(" , Unknown), (identifier, "addr" , Unknown),
(comma, "," , Unknown), (numeric_constant, "0" , Unknown), (comma, "," , Unknown), (identifier, "N" , Unknown),
(star, "*" , PointerOrReference) 👈, (identifier, "two" , StartOfName), (r_paren, ")" , Unknown), (semi, ";" , Unknown),
(r_brace, "}" , Unknown), (eof, "" , Unknown)}

How about judging whether the FunctionLBrace exists as the opener of the outer context?

[owenca]

How about judging whether the FunctionLBrace exists as the opener of the outer context?

That wouldn't work as we must also handle function calls at the top level when dealing with macro definitions.