From 8f738ac6d469ce3ebefe3d1c9dadcc1eda56a61c Mon Sep 17 00:00:00 2001
From: Ilya Biryukov <ibiryukov@google.com>
Date: Tue, 12 Sep 2017 08:35:57 +0000
Subject: [PATCH] Fix recording preamble's conditional stack in skipped PP
 branches.

Summary:
This fixes PR34547.
`Lexer::LexEndOfFile` handles recording of ConditionalStack for
preamble and reporting errors about unmatched conditionalal PP
directives.
However, SkipExcludedConditionalBlock contianed duplicated logic for
reporting errors and clearing ConditionalStack, but not for preamble
recording.

This fix removes error reporting logic from
`SkipExcludedConditionalBlock`, unmatched PP conditionals are now
reported inside `Lexer::LexEndOfFile`.

Reviewers: erikjv, klimek, bkramer

Reviewed By: erikjv

Subscribers: nik, cfe-commits

Differential Revision: https://reviews.llvm.org/D37700

llvm-svn: 313014
---
 clang/lib/Lex/PPDirectives.cpp                        | 11 ++---------
 .../preamble-conditionals-inverted-with-error.cpp     |  8 ++++++++
 clang/test/Index/preamble-conditionals-inverted.cpp   |  8 ++++++++
 3 files changed, 18 insertions(+), 9 deletions(-)
 create mode 100644 clang/test/Index/preamble-conditionals-inverted-with-error.cpp
 create mode 100644 clang/test/Index/preamble-conditionals-inverted.cpp

diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index 556e76356da4..eb9f11f3d4df 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -383,15 +383,8 @@ void Preprocessor::SkipExcludedConditionalBlock(const Token &HashToken,
 
     // If this is the end of the buffer, we have an error.
     if (Tok.is(tok::eof)) {
-      // Emit errors for each unterminated conditional on the stack, including
-      // the current one.
-      while (!CurPPLexer->ConditionalStack.empty()) {
-        if (CurLexer->getFileLoc() != CodeCompletionFileLoc)
-          Diag(CurPPLexer->ConditionalStack.back().IfLoc,
-               diag::err_pp_unterminated_conditional);
-        CurPPLexer->ConditionalStack.pop_back();
-      }
-
+      // We don't emit errors for unterminated conditionals here,
+      // Lexer::LexEndOfFile can do that propertly.
       // Just return and let the caller lex after this #include.
       break;
     }
diff --git a/clang/test/Index/preamble-conditionals-inverted-with-error.cpp b/clang/test/Index/preamble-conditionals-inverted-with-error.cpp
new file mode 100644
index 000000000000..95b0695b8733
--- /dev/null
+++ b/clang/test/Index/preamble-conditionals-inverted-with-error.cpp
@@ -0,0 +1,8 @@
+// RUN: env CINDEXTEST_EDITING=1 c-index-test -test-load-source-reparse 5 \
+// RUN:                                       local -std=c++14 %s 2>&1 \
+// RUN: | FileCheck %s
+#ifdef FOO_H
+
+void foo();
+
+// CHECK: preamble-conditionals-inverted-with-error.cpp:4:2: error: unterminated conditional directive
diff --git a/clang/test/Index/preamble-conditionals-inverted.cpp b/clang/test/Index/preamble-conditionals-inverted.cpp
new file mode 100644
index 000000000000..1d67ccb61a02
--- /dev/null
+++ b/clang/test/Index/preamble-conditionals-inverted.cpp
@@ -0,0 +1,8 @@
+// RUN: env CINDEXTEST_EDITING=1 c-index-test -test-load-source-reparse 5 \
+// RUN:                                       local -std=c++14 %s 2>&1 \
+// RUN: | FileCheck %s --implicit-check-not "error:"
+#ifdef FOO_H
+
+void foo();
+
+#endif