[clang-tools-extra] [clang-tidy][misleading-indentation]ignore false-positives for line started with empty macro (PR #75061)

[Congcong Cai via cfe-commits]

https://github.com/HerrCai0907 created https://github.com/llvm/llvm-project/pull/75061

Fixes: #71767

>From e710a0568c73e87296b4df03ac6746766bd87c3a Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0907 at 163.com>
Date: Mon, 11 Dec 2023 23:32:32 +0800
Subject: [PATCH] [clang-tidy][misleading-indentation]ignore false-positives
 for line started with empty macro

Fixes: #71767
---
 .../MisleadingIndentationCheck.cpp            | 24 ++++++++++++++++---
 .../readability/MisleadingIndentationCheck.h  |  3 ++-
 clang-tools-extra/docs/ReleaseNotes.rst       |  4 ++++
 .../readability/misleading-indentation.cpp    |  9 +++++++
 4 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/readability/MisleadingIndentationCheck.cpp b/clang-tools-extra/clang-tidy/readability/MisleadingIndentationCheck.cpp
index 2c011f5c0e6904..a096c0e383130a 100644
--- a/clang-tools-extra/clang-tidy/readability/MisleadingIndentationCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/MisleadingIndentationCheck.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "MisleadingIndentationCheck.h"
+#include "../utils/LexerUtils.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 
@@ -51,8 +52,22 @@ void MisleadingIndentationCheck::danglingElseCheck(const SourceManager &SM,
     diag(ElseLoc, "different indentation for 'if' and corresponding 'else'");
 }
 
-void MisleadingIndentationCheck::missingBracesCheck(const SourceManager &SM,
-                                                    const CompoundStmt *CStmt) {
+static bool isAtStartOfLineIncludingEmptyMacro(SourceLocation NextLoc,
+                                               const SourceManager &SM,
+                                               const LangOptions &LangOpts) {
+  NextLoc.dump(SM);
+  const SourceLocation BeforeLoc =
+      utils::lexer::getPreviousTokenAndStart(NextLoc, SM, LangOpts).second;
+  if (SM.getExpansionLineNumber(BeforeLoc) ==
+      SM.getExpansionLineNumber(NextLoc)) {
+    return false;
+  }
+  return true;
+}
+
+void MisleadingIndentationCheck::missingBracesCheck(
+    const SourceManager &SM, const CompoundStmt *CStmt,
+    const LangOptions &LangOpts) {
   const static StringRef StmtNames[] = {"if", "for", "while"};
   for (unsigned int I = 0; I < CStmt->size() - 1; I++) {
     const Stmt *CurrentStmt = CStmt->body_begin()[I];
@@ -92,6 +107,8 @@ void MisleadingIndentationCheck::missingBracesCheck(const SourceManager &SM,
 
     if (NextLoc.isInvalid() || NextLoc.isMacroID())
       continue;
+    if (!isAtStartOfLineIncludingEmptyMacro(NextLoc, SM, LangOpts))
+      continue;
 
     if (SM.getExpansionColumnNumber(InnerLoc) ==
         SM.getExpansionColumnNumber(NextLoc)) {
@@ -117,7 +134,8 @@ void MisleadingIndentationCheck::check(const MatchFinder::MatchResult &Result) {
     danglingElseCheck(*Result.SourceManager, Result.Context, If);
 
   if (const auto *CStmt = Result.Nodes.getNodeAs<CompoundStmt>("compound"))
-    missingBracesCheck(*Result.SourceManager, CStmt);
+    missingBracesCheck(*Result.SourceManager, CStmt,
+                       Result.Context->getLangOpts());
 }
 
 } // namespace clang::tidy::readability
diff --git a/clang-tools-extra/clang-tidy/readability/MisleadingIndentationCheck.h b/clang-tools-extra/clang-tidy/readability/MisleadingIndentationCheck.h
index c336abbc7c4a91..9c92fc1e18b6f3 100644
--- a/clang-tools-extra/clang-tidy/readability/MisleadingIndentationCheck.h
+++ b/clang-tools-extra/clang-tidy/readability/MisleadingIndentationCheck.h
@@ -32,7 +32,8 @@ class MisleadingIndentationCheck : public ClangTidyCheck {
 private:
   void danglingElseCheck(const SourceManager &SM, ASTContext *Context,
                          const IfStmt *If);
-  void missingBracesCheck(const SourceManager &SM, const CompoundStmt *CStmt);
+  void missingBracesCheck(const SourceManager &SM, const CompoundStmt *CStmt,
+                          const LangOptions &LangOpts);
 };
 
 } // namespace clang::tidy::readability
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 6d91748e4cef18..85438ce795b34c 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -453,6 +453,10 @@ Changes in existing checks
   <clang-tidy/checks/readability/non-const-parameter>` check to ignore
   false-positives in initializer list of record.
 
+- Improved :doc:`readability-misleading-indentation
+  <clang-tidy/checks/readability/misleading-indentation>` check to ignore
+  false-positives for line started with empty macro.
+
 - Improved :doc:`readability-static-accessed-through-instance
   <clang-tidy/checks/readability/static-accessed-through-instance>` check to
   identify calls to static member functions with out-of-class inline definitions.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/misleading-indentation.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/misleading-indentation.cpp
index aea0618d120db6..5d4d60f5f1a351 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/misleading-indentation.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/misleading-indentation.cpp
@@ -4,6 +4,8 @@ void foo1();
 void foo2();
 void foo3();
 
+#define E
+
 #define BLOCK \
   if (cond1)  \
     foo1();   \
@@ -109,6 +111,13 @@ void f()
   }
 
   BLOCK
+
+  if (cond1)
+    foo1();
+  else
+    foo2();
+  E foo3();
+  // CHECK-MESSAGES-NOT: :[[@LINE-1]]readability-misleading-indentation
 }
 
 void g(bool x) {