Clang: Avoid parse loop if libclang crashed or file vanished

Remember whether clang_parseTranslationUnit() or
clang_reparseTranslationUnit() failed the last time and do not trigger
parse/reparse again.

Also, check whether the main file exists before reparsing.

Task-number: QTCREATORBUG-16051
Task-number: QTCREATORBUG-16140
Change-Id: Ied39e66a18032854911229898573941fe2ada35b
Reviewed-by: Erik Verbruggen <erik.verbruggen@qt.io>

7 files changed, 201 insertions, 24 deletions

diff --git a/src/tools/clangbackend/ipcsource/clangbackendclangipc-source.pri b/src/tools/clangbackend/ipcsource/clangbackendclangipc-source.pri
index 344a037207..6140f1ca88 100644
--- a/src/tools/clangbackend/ipcsource/clangbackendclangipc-source.pri
+++ b/src/tools/clangbackend/ipcsource/clangbackendclangipc-source.pri
@@ -12,6 +12,7 @@ HEADERS += $$PWD/clangipcserver.h \
     $$PWD/projects.h \
     $$PWD/translationunits.h \
     $$PWD/translationunitparseerrorexception.h \
+    $$PWD/translationunitreparseerrorexception.h \
     $$PWD/projectpart.h \
     $$PWD/translationunitfilenotexitexception.h \
     $$PWD/translationunitdoesnotexistexception.h \
@@ -46,6 +47,7 @@ SOURCES += $$PWD/clangipcserver.cpp \
     $$PWD/projects.cpp \
     $$PWD/translationunits.cpp \
     $$PWD/translationunitparseerrorexception.cpp \
+    $$PWD/translationunitreparseerrorexception.cpp \
     $$PWD/projectpart.cpp \
     $$PWD/translationunitfilenotexitexception.cpp \
     $$PWD/translationunitdoesnotexistexception.cpp \
diff --git a/src/tools/clangbackend/ipcsource/clangtranslationunit.cpp b/src/tools/clangbackend/ipcsource/clangtranslationunit.cpp
index 3460e6ff46..0644c53e3f 100644
--- a/src/tools/clangbackend/ipcsource/clangtranslationunit.cpp
+++ b/src/tools/clangbackend/ipcsource/clangtranslationunit.cpp
@@ -39,6 +39,7 @@
 #include "translationunitfilenotexitexception.h"
 #include "translationunitisnullexception.h"
 #include "translationunitparseerrorexception.h"
+#include "translationunitreparseerrorexception.h"
 #include "translationunits.h"
 #include "unsavedfiles.h"
 
@@ -76,6 +77,8 @@ public:
     Utf8StringVector fileArguments;
     Utf8String filePath;
     CXTranslationUnit translationUnit = nullptr;
+    CXErrorCode parseErrorCode = CXError_Success;
+    int reparseErrorCode = 0;
     CXIndex index = nullptr;
     uint documentRevision = 0;
     bool needsToBeReparsed = false;
@@ -155,6 +158,16 @@ void TranslationUnit::reparse() const
     reparseTranslationUnit();
 }
 
+bool TranslationUnit::parseWasSuccessful() const
+{
+    return d->parseErrorCode == CXError_Success;
+}
+
+bool TranslationUnit::reparseWasSuccessful() const
+{
+    return d->reparseErrorCode == 0;
+}
+
 CXIndex TranslationUnit::index() const
 {
     checkIfNull();
@@ -350,7 +363,7 @@ void TranslationUnit::checkIfNull() const
 
 void TranslationUnit::checkIfFileExists() const
 {
-    if (!QFileInfo::exists(d->filePath.toString()))
+    if (!fileExists())
         throw TranslationUnitFileNotExitsException(d->filePath);
 }
 
@@ -396,16 +409,16 @@ void TranslationUnit::createTranslationUnitIfNeeded() const
         if (isVerboseModeEnabled())
             args.print();
 
-        CXErrorCode errorCode = clang_parseTranslationUnit2(index(),
-                                                            NULL,
-                                                            args.data(),
-                                                            args.count(),
-                                                            unsavedFiles().cxUnsavedFiles(),
-                                                            unsavedFiles().count(),
-                                                            defaultOptions(),
-                                                            &d->translationUnit);
+        d->parseErrorCode = clang_parseTranslationUnit2(index(),
+                                                        NULL,
+                                                        args.data(),
+                                                        args.count(),
+                                                        unsavedFiles().cxUnsavedFiles(),
+                                                        unsavedFiles().count(),
+                                                        defaultOptions(),
+                                                        &d->translationUnit);
 
-        checkTranslationUnitErrorCode(errorCode);
+        checkParseErrorCode();
 
         updateIncludeFilePaths();
 
@@ -413,22 +426,33 @@ void TranslationUnit::createTranslationUnitIfNeeded() const
     }
 }
 
-void TranslationUnit::checkTranslationUnitErrorCode(CXErrorCode errorCode) const
+void TranslationUnit::checkParseErrorCode() const
 {
-    switch (errorCode) {
-        case CXError_Success: break;
-        default: throw TranslationUnitParseErrorException(d->filePath,
-                                                          d->projectPart.projectPartId(),
-                                                          errorCode);
+    if (!parseWasSuccessful()) {
+        throw TranslationUnitParseErrorException(d->filePath,
+                                                 d->projectPart.projectPartId(),
+                                                 d->parseErrorCode);
+    }
+}
+
+void TranslationUnit::checkReparseErrorCode() const
+{
+    if (!reparseWasSuccessful()) {
+        throw TranslationUnitReparseErrorException(d->filePath,
+                                                   d->projectPart.projectPartId(),
+                                                   d->reparseErrorCode);
     }
 }
 
 void TranslationUnit::reparseTranslationUnit() const
 {
-    clang_reparseTranslationUnit(d->translationUnit,
-                                 unsavedFiles().count(),
-                                 unsavedFiles().cxUnsavedFiles(),
-                                 clang_defaultReparseOptions(d->translationUnit));
+    d->reparseErrorCode = clang_reparseTranslationUnit(
+                                    d->translationUnit,
+                                    unsavedFiles().count(),
+                                    unsavedFiles().cxUnsavedFiles(),
+                                    clang_defaultReparseOptions(d->translationUnit));
+
+    checkReparseErrorCode();
 
     updateIncludeFilePaths();
 
@@ -474,6 +498,19 @@ void TranslationUnit::updateIncludeFilePaths() const
     d->translationUnits.addWatchedFiles(d->dependedFilePaths);
 }
 
+bool TranslationUnit::fileExists() const
+{
+    return QFileInfo::exists(d->filePath.toString());
+}
+
+bool TranslationUnit::isIntact() const
+{
+    return !isNull()
+        && fileExists()
+        && parseWasSuccessful()
+        && reparseWasSuccessful();
+}
+
 CommandLineArguments TranslationUnit::commandLineArguments() const
 {
     return CommandLineArguments(d->filePath.constData(),
diff --git a/src/tools/clangbackend/ipcsource/clangtranslationunit.h b/src/tools/clangbackend/ipcsource/clangtranslationunit.h
index 9a311b62bf..553a3f28de 100644
--- a/src/tools/clangbackend/ipcsource/clangtranslationunit.h
+++ b/src/tools/clangbackend/ipcsource/clangtranslationunit.h
@@ -91,6 +91,8 @@ public:
     void reset();
     void reparse() const;
 
+    bool isIntact() const;
+
     CXIndex index() const;
     CXTranslationUnit cxTranslationUnit() const;
     CXTranslationUnit cxTranslationUnitWithoutReparsing() const;
@@ -150,10 +152,14 @@ private:
     bool projectPartIsOutdated() const;
     bool isMainFileAndExistsOrIsOtherFile(const Utf8String &filePath) const;
     void createTranslationUnitIfNeeded() const;
-    void checkTranslationUnitErrorCode(CXErrorCode errorCode) const;
+    void checkParseErrorCode() const;
+    void checkReparseErrorCode() const;
     void reparseTranslationUnit() const;
     void reparseTranslationUnitIfFilesAreChanged() const;
+    bool parseWasSuccessful() const;
+    bool reparseWasSuccessful() const;
     void updateIncludeFilePaths() const;
+    bool fileExists() const;
     static void includeCallback(CXFile included_file,
                                 CXSourceLocation * /*inclusion_stack*/,
                                 unsigned /*include_len*/,
diff --git a/src/tools/clangbackend/ipcsource/translationunitparseerrorexception.cpp b/src/tools/clangbackend/ipcsource/translationunitparseerrorexception.cpp
index 3cd99c53e8..27f1799e09 100644
--- a/src/tools/clangbackend/ipcsource/translationunitparseerrorexception.cpp
+++ b/src/tools/clangbackend/ipcsource/translationunitparseerrorexception.cpp
@@ -65,12 +65,13 @@ static const char *errorCodeToText(CXErrorCode errorCode)
 const char *TranslationUnitParseErrorException::what() const Q_DECL_NOEXCEPT
 {
     if (what_.isEmpty()) {
-        what_ += Utf8StringLiteral("Parse error for file ")
+        what_ += Utf8StringLiteral("clang_parseTranslationUnit() failed for file ")
                 + filePath()
                 + Utf8StringLiteral(" in project ")
                 + projectPartId()
                 + Utf8StringLiteral(": ")
-                + Utf8String::fromUtf8(errorCodeToText(errorCode_));
+                + Utf8String::fromUtf8(errorCodeToText(errorCode_))
+                + Utf8StringLiteral(".");
     }
 
     return what_.constData();
diff --git a/src/tools/clangbackend/ipcsource/translationunitreparseerrorexception.cpp b/src/tools/clangbackend/ipcsource/translationunitreparseerrorexception.cpp
new file mode 100644
index 0000000000..6f1e7f0d7d
--- /dev/null
+++ b/src/tools/clangbackend/ipcsource/translationunitreparseerrorexception.cpp
@@ -0,0 +1,68 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "translationunitreparseerrorexception.h"
+
+#include <QString>
+
+namespace ClangBackEnd {
+
+TranslationUnitReparseErrorException::TranslationUnitReparseErrorException(
+        const Utf8String &filePath,
+        const Utf8String &projectPartId,
+        int errorCode)
+    : filePath_(filePath),
+      projectPartId_(projectPartId),
+      errorCode_(errorCode)
+{
+}
+
+const Utf8String &TranslationUnitReparseErrorException::filePath() const
+{
+    return filePath_;
+}
+
+const Utf8String &TranslationUnitReparseErrorException::projectPartId() const
+{
+    return projectPartId_;
+}
+
+const char *TranslationUnitReparseErrorException::what() const Q_DECL_NOEXCEPT
+{
+    if (what_.isEmpty()) {
+        what_ += Utf8StringLiteral("clang_reparseTranslationUnit() failed for file ")
+                + filePath()
+                + Utf8StringLiteral(" in project ")
+                + projectPartId()
+                + Utf8StringLiteral(": ")
+                + Utf8String::fromString(QString::number(errorCode_))
+                + Utf8StringLiteral(".");
+    }
+
+    return what_.constData();
+}
+
+} // namespace ClangBackEnd
+
diff --git a/src/tools/clangbackend/ipcsource/translationunitreparseerrorexception.h b/src/tools/clangbackend/ipcsource/translationunitreparseerrorexception.h
new file mode 100644
index 0000000000..126a24c7e9
--- /dev/null
+++ b/src/tools/clangbackend/ipcsource/translationunitreparseerrorexception.h
@@ -0,0 +1,61 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include <utf8string.h>
+
+#include <clang-c/Index.h>
+
+#include <exception>
+
+namespace ClangBackEnd {
+
+class TranslationUnitReparseErrorException : public std::exception
+{
+public:
+    TranslationUnitReparseErrorException(const Utf8String &filePath,
+                                         const Utf8String &projectPartId,
+                                         int errorCode);
+
+    const Utf8String &filePath() const;
+    const Utf8String &projectPartId() const;
+
+    const char *what() const Q_DECL_NOEXCEPT override;
+
+#if defined(__GNUC__) && !defined(__clang__)
+#  if !__GNUC_PREREQ(4,8)
+    ~TranslationUnitReparseErrorException() noexcept {}
+#  endif
+#endif
+
+private:
+    Utf8String filePath_;
+    Utf8String projectPartId_;
+    int errorCode_;
+    mutable Utf8String what_;
+};
+
+} // namespace ClangBackEnd
diff --git a/src/tools/clangbackend/ipcsource/translationunits.cpp b/src/tools/clangbackend/ipcsource/translationunits.cpp
index 5b118a9652..6f9defc356 100644
--- a/src/tools/clangbackend/ipcsource/translationunits.cpp
+++ b/src/tools/clangbackend/ipcsource/translationunits.cpp
@@ -199,7 +199,9 @@ namespace {
 
 bool translationUnitHasNewDocumentAnnotations(const TranslationUnit &translationUnit)
 {
-    return translationUnit.hasNewDiagnostics() || translationUnit.hasNewHighlightingInformations();
+    return translationUnit.isIntact()
+        && (translationUnit.hasNewDiagnostics()
+            || translationUnit.hasNewHighlightingInformations());
 }
 
 }