From 15f121e853846d7c74c243a4249a069dd67ca166 Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano@gmail.com>
Date: Sun, 4 Dec 2022 13:52:01 -0800
Subject: [PATCH] [clang-format] Fix an assertion failure in block parsing

This assertion failure was introduced in 9ed2e68c9ae5 and is
manifested when both RemoveBracesLLVM and MacroBlockBegin are set.

Fixes #59335.

Differential Revision: https://reviews.llvm.org/D139281
---
 clang/lib/Format/FormatToken.h           |  6 ------
 clang/lib/Format/UnwrappedLineParser.cpp | 14 +++++++++++---
 clang/lib/Format/UnwrappedLineParser.h   |  1 +
 clang/unittests/Format/FormatTest.cpp    |  7 +++++++
 4 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/clang/lib/Format/FormatToken.h b/clang/lib/Format/FormatToken.h
index 8751537..e8c6cd9 100644
--- a/clang/lib/Format/FormatToken.h
+++ b/clang/lib/Format/FormatToken.h
@@ -1785,12 +1785,6 @@ struct AdditionalKeywords {
                                     kw_input, kw_output, kw_sequence)));
   }
 
-  /// Whether the token begins a block.
-  bool isBlockBegin(const FormatToken &Tok, const FormatStyle &Style) const {
-    return Tok.is(TT_MacroBlockBegin) ||
-           (Style.isVerilog() ? isVerilogBegin(Tok) : Tok.is(tok::l_brace));
-  }
-
 private:
   /// The JavaScript keywords beyond the C++ keyword set.
   std::unordered_set<IdentifierInfo *> JsExtraKeywords;
diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index d665a4b..df8cff6 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -2739,6 +2739,14 @@ bool UnwrappedLineParser::handleCppAttributes() {
   return false;
 }
 
+/// Returns whether \c Tok begins a block.
+bool UnwrappedLineParser::isBlockBegin(const FormatToken &Tok) const {
+  // FIXME: rename the function or make
+  // Tok.isOneOf(tok::l_brace, TT_MacroBlockBegin) work.
+  return Style.isVerilog() ? Keywords.isVerilogBegin(Tok)
+                           : Tok.is(tok::l_brace);
+}
+
 FormatToken *UnwrappedLineParser::parseIfThenElse(IfStmtKind *IfKind,
                                                   bool KeepBraces) {
   assert(FormatTok->is(tok::kw_if) && "'if' expected");
@@ -2764,7 +2772,7 @@ FormatToken *UnwrappedLineParser::parseIfThenElse(IfStmtKind *IfKind,
   FormatToken *IfLeftBrace = nullptr;
   IfStmtKind IfBlockKind = IfStmtKind::NotIf;
 
-  if (Keywords.isBlockBegin(*FormatTok, Style)) {
+  if (isBlockBegin(*FormatTok)) {
     FormatTok->setFinalizedType(TT_ControlStatementLBrace);
     IfLeftBrace = FormatTok;
     CompoundStatementIndenter Indenter(this, Style, Line->Level);
@@ -2796,7 +2804,7 @@ FormatToken *UnwrappedLineParser::parseIfThenElse(IfStmtKind *IfKind,
     }
     nextToken();
     handleAttributes();
-    if (Keywords.isBlockBegin(*FormatTok, Style)) {
+    if (isBlockBegin(*FormatTok)) {
       const bool FollowedByIf = Tokens->peekNextToken()->is(tok::kw_if);
       FormatTok->setFinalizedType(TT_ElseLBrace);
       ElseLeftBrace = FormatTok;
@@ -3063,7 +3071,7 @@ void UnwrappedLineParser::parseNew() {
 void UnwrappedLineParser::parseLoopBody(bool KeepBraces, bool WrapRightBrace) {
   keepAncestorBraces();
 
-  if (Keywords.isBlockBegin(*FormatTok, Style)) {
+  if (isBlockBegin(*FormatTok)) {
     if (!KeepBraces)
       FormatTok->setFinalizedType(TT_ControlStatementLBrace);
     FormatToken *LeftBrace = FormatTok;
diff --git a/clang/lib/Format/UnwrappedLineParser.h b/clang/lib/Format/UnwrappedLineParser.h
index 88810ad..ce59180 100644
--- a/clang/lib/Format/UnwrappedLineParser.h
+++ b/clang/lib/Format/UnwrappedLineParser.h
@@ -143,6 +143,7 @@ private:
   void parseUnbracedBody(bool CheckEOF = false);
   void handleAttributes();
   bool handleCppAttributes();
+  bool isBlockBegin(const FormatToken &Tok) const;
   FormatToken *parseIfThenElse(IfStmtKind *IfKind, bool KeepBraces = false);
   void parseTryCatch();
   void parseLoopBody(bool KeepBraces, bool WrapRightBrace);
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index f895eb4..00f5c4b 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -6602,6 +6602,13 @@ TEST_F(FormatTest, FormatBeginBlockEndMacros) {
                "  x = 1;\n"
                "FOO_END(Baz)",
                Style);
+
+  Style.RemoveBracesLLVM = true;
+  verifyNoCrash("for (;;)\n"
+                "  FOO_BEGIN\n"
+                "    foo();\n"
+                "  FOO_END",
+                Style);
 }
 
 //===----------------------------------------------------------------------===//
-- 
2.7.4