[clang] [clang-format] Option to ignore PP directives (PR #70338)

[via cfe-commits]

https://github.com/tomekpaszek created https://github.com/llvm/llvm-project/pull/70338

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>From 8404d703d58658593e6112b478533edb124cd0e1 Mon Sep 17 00:00:00 2001
From: Tomek Paszek <tomek at unity3d.com>
Date: Thu, 26 Oct 2023 16:19:36 +0200
Subject: [PATCH] Added an option to ignore macro definitions.

---
 clang/include/clang/Format/Format.h         |  5 ++++-
 clang/lib/Format/Format.cpp                 |  2 ++
 clang/lib/Format/UnwrappedLineFormatter.cpp |  4 +++-
 clang/unittests/Format/ConfigParseTest.cpp  |  1 +
 clang/unittests/Format/FormatTest.cpp       | 16 ++++++++++++++++
 5 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
index 3e9d1915badd87f..632d45c6275472e 100644
--- a/clang/include/clang/Format/Format.h
+++ b/clang/include/clang/Format/Format.h
@@ -4648,6 +4648,8 @@ struct FormatStyle {
   /// \version 11
   std::vector<std::string> WhitespaceSensitiveMacros;
 
+  bool IgnorePPDefinitions;
+
   bool operator==(const FormatStyle &R) const {
     return AccessModifierOffset == R.AccessModifierOffset &&
            AlignAfterOpenBracket == R.AlignAfterOpenBracket &&
@@ -4810,7 +4812,8 @@ struct FormatStyle {
            UseTab == R.UseTab &&
            VerilogBreakBetweenInstancePorts ==
                R.VerilogBreakBetweenInstancePorts &&
-           WhitespaceSensitiveMacros == R.WhitespaceSensitiveMacros;
+           WhitespaceSensitiveMacros == R.WhitespaceSensitiveMacros &&
+           IgnorePPDefinitions == R.IgnorePPDefinitions;
   }
 
   std::optional<FormatStyle> GetLanguageStyle(LanguageKind Language) const;
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index edb33f4af4defef..820408ae1a272e3 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -1127,6 +1127,7 @@ template <> struct MappingTraits<FormatStyle> {
                    Style.VerilogBreakBetweenInstancePorts);
     IO.mapOptional("WhitespaceSensitiveMacros",
                    Style.WhitespaceSensitiveMacros);
+    IO.mapOptional("IgnorePPDefinitions", Style.IgnorePPDefinitions);
 
     // If AlwaysBreakAfterDefinitionReturnType was specified but
     // AlwaysBreakAfterReturnType was not, initialize the latter from the
@@ -1591,6 +1592,7 @@ FormatStyle getLLVMStyle(FormatStyle::LanguageKind Language) {
   LLVMStyle.WhitespaceSensitiveMacros.push_back("NS_SWIFT_NAME");
   LLVMStyle.WhitespaceSensitiveMacros.push_back("PP_STRINGIZE");
   LLVMStyle.WhitespaceSensitiveMacros.push_back("STRINGIZE");
+  LLVMStyle.IgnorePPDefinitions = false;
 
   LLVMStyle.PenaltyBreakAssignment = prec::Assignment;
   LLVMStyle.PenaltyBreakComment = 300;
diff --git a/clang/lib/Format/UnwrappedLineFormatter.cpp b/clang/lib/Format/UnwrappedLineFormatter.cpp
index 280485d9a90d1bf..21adb4b4b225b45 100644
--- a/clang/lib/Format/UnwrappedLineFormatter.cpp
+++ b/clang/lib/Format/UnwrappedLineFormatter.cpp
@@ -1354,7 +1354,9 @@ unsigned UnwrappedLineFormatter::format(
 
     bool FixIndentation = (FixBadIndentation || ContinueFormatting) &&
                           Indent != TheLine.First->OriginalColumn;
-    bool ShouldFormat = TheLine.Affected || FixIndentation;
+    bool ShouldFormat = (TheLine.Affected || FixIndentation);
+    if (Style.IgnorePPDefinitions && TheLine.Type == LT_PreprocessorDirective)
+      ShouldFormat = false;
     // We cannot format this line; if the reason is that the line had a
     // parsing error, remember that.
     if (ShouldFormat && TheLine.Type == LT_Invalid && Status) {
diff --git a/clang/unittests/Format/ConfigParseTest.cpp b/clang/unittests/Format/ConfigParseTest.cpp
index f90ed178d99c286..3e1be1abdda0670 100644
--- a/clang/unittests/Format/ConfigParseTest.cpp
+++ b/clang/unittests/Format/ConfigParseTest.cpp
@@ -198,6 +198,7 @@ TEST(ConfigParseTest, ParsesConfigurationBools) {
   CHECK_PARSE_BOOL(SpaceBeforeRangeBasedForLoopColon);
   CHECK_PARSE_BOOL(SpaceBeforeSquareBrackets);
   CHECK_PARSE_BOOL(VerilogBreakBetweenInstancePorts);
+  CHECK_PARSE_BOOL(IgnorePPDefinitions);
 
   CHECK_PARSE_NESTED_BOOL(AlignConsecutiveShortCaseStatements, Enabled);
   CHECK_PARSE_NESTED_BOOL(AlignConsecutiveShortCaseStatements,
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index b2d84f2ee389551..659132dcb9c3970 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -24153,6 +24153,22 @@ TEST_F(FormatTest, WhitespaceSensitiveMacros) {
   verifyNoChange("FOO(String-ized&Messy+But: :Still=Intentional);", Style);
 }
 
+TEST_F(FormatTest, IgnorePPDefinitions) {
+  FormatStyle Style = getLLVMStyle();
+  Style.IgnorePPDefinitions = true;
+
+  verifyNoChange("#define  A", Style);
+  verifyNoChange("#define A   b", Style);
+  verifyNoChange("#define A  (  args   )", Style);
+  verifyNoChange("#define A  (  args   )  =  func  (  args  )", Style);
+  verifyNoChange("#define TEXT Text . With periods.", Style);
+  verifyNoChange("#define TEXT \\\nLine  number  one .  \\\nNumber  two .",
+                 Style);
+
+  // TODO
+  // verifyNoChange("/* comment */ #define A  (  args   )", Style);
+}
+
 TEST_F(FormatTest, VeryLongNamespaceCommentSplit) {
   // These tests are not in NamespaceEndCommentsFixerTest because that doesn't
   // test its interaction with line wrapping