[PATCH] D106204: [Lex] Consider a PCH header-guarded even with #endif truncated

[Sam McCall via Phabricator via cfe-commits]

sammccall created this revision.
sammccall added a reviewer: kadircet.
Herald added subscribers: usaxena95, arphaman.
sammccall requested review of this revision.
Herald added projects: clang, clang-tools-extra.
Herald added a subscriber: cfe-commits.

This seems to be a more useful behavior for tools that use preambles.
I believe it doesn't affect real compiles: the PCH is only included once
when used, and recursive inclusion of the main-file *within* the PCH
isn't supported in any case.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D106204

Files:
  clang-tools-extra/clangd/unittests/ParsedASTTests.cpp
  clang/lib/Lex/Lexer.cpp


Index: clang/lib/Lex/Lexer.cpp
===================================================================
--- clang/lib/Lex/Lexer.cpp
+++ clang/lib/Lex/Lexer.cpp
@@ -2793,6 +2793,11 @@
 
   if (PP->isRecordingPreamble() && PP->isInPrimaryFile()) {
     PP->setRecordedPreambleConditionalStack(ConditionalStack);
+    // If the preamble cuts off the end of a header guard, consider it guarded.
+    // The guard is valid for the preamble content itself, and for tools the
+    // most useful answer is "yes, this file has a header guard".
+    if (!ConditionalStack.empty())
+      MIOpt.ExitTopLevelConditional();
     ConditionalStack.clear();
   }
 
Index: clang-tools-extra/clangd/unittests/ParsedASTTests.cpp
===================================================================
--- clang-tools-extra/clangd/unittests/ParsedASTTests.cpp
+++ clang-tools-extra/clangd/unittests/ParsedASTTests.cpp
@@ -667,7 +667,7 @@
   EXPECT_FALSE(mainIsGuarded(TU.build()));
 
   TU.Code = guard(";");
-  EXPECT_FALSE(mainIsGuarded(TU.build())); // FIXME: true
+  EXPECT_TRUE(mainIsGuarded(TU.build()));
 
   TU.Code = once(";");
   EXPECT_TRUE(mainIsGuarded(TU.build()));
@@ -751,7 +751,7 @@
   )cpp";
   AST = TU.build();
   EXPECT_THAT(*AST.getDiagnostics(), IsEmpty());
-  EXPECT_FALSE(mainIsGuarded(AST)); // FIXME: true
+  EXPECT_TRUE(mainIsGuarded(AST));
 }
 
 // Tests how we handle common idioms for splitting a header-only library
@@ -785,7 +785,7 @@
   TU.AdditionalFiles = {{"impl.h", Implementation}};
   auto AST = TU.build();
   EXPECT_THAT(*AST.getDiagnostics(), IsEmpty());
-  EXPECT_FALSE(mainIsGuarded(AST)); // FIXME: true
+  EXPECT_TRUE(mainIsGuarded(AST));
   // Slightly harder: the `#pragma once` is part of the preamble, and we
   // need to transfer it to the main file's HeaderFileInfo.
   TU.Code = once(Interface);


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