new loplugin indentation

look for mixed indentation in compound statements, which makes them hard
to read, and sometimes makes it look like a statement is associated with
a nearby if/for

Change-Id: Ic8429cee1f9a86d938097a4a8769a2bce97b3361
Reviewed-on: https://gerrit.libreoffice.org/63283
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 229 insertions, 0 deletions

diff --git a/compilerplugins/clang/indentation.cxx b/compilerplugins/clang/indentation.cxx
new file mode 100644
index 000000000000..c63bc58c06d9
--- /dev/null
+++ b/compilerplugins/clang/indentation.cxx
@@ -0,0 +1,229 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * Based on LLVM/Clang.
+ *
+ * This file is distributed under the University of Illinois Open Source
+ * License. See LICENSE.TXT for details.
+ *
+ */
+
+#include <cassert>
+#include <string>
+#include <iostream>
+#include <fstream>
+#include <set>
+#include "plugin.hxx"
+
+/*
+Check for child statements inside a compound statement that do not share the same indentation.
+
+TODO if an open-brace starts on a new line by itself, check that it lines up with it's closing-brace
+TODO else should line up with if
+*/
+
+namespace
+{
+class Indentation : public loplugin::FilteringPlugin<Indentation>
+{
+public:
+    explicit Indentation(loplugin::InstantiationData const& data)
+        : FilteringPlugin(data)
+    {
+    }
+
+    virtual void run() override
+    {
+        std::string fn(handler.getMainFileName());
+        loplugin::normalizeDotDotInFilePath(fn);
+        // include another file to build a table
+        if (fn == SRCDIR "/sc/source/core/tool/cellkeytranslator.cxx")
+            return;
+        // weird structure
+        if (fn == SRCDIR "/sc/source/core/tool/compiler.cxx")
+            return;
+        // looks like lex/yacc output
+        if (fn == SRCDIR "/hwpfilter/source/grammar.cxx")
+            return;
+        // TODO need to learn to handle attributes like "[[maybe_unused]]"
+        if (fn == SRCDIR "/binaryurp/source/bridge.cxx")
+            return;
+        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+    }
+
+    bool VisitCompoundStmt(CompoundStmt const*);
+    bool TraverseSwitchStmt(SwitchStmt*);
+    bool VisitSwitchStmt(SwitchStmt const*);
+
+private:
+    Stmt const* switchStmtBody = nullptr;
+};
+
+bool Indentation::TraverseSwitchStmt(SwitchStmt* switchStmt)
+{
+    auto prev = switchStmtBody;
+    switchStmtBody = switchStmt->getBody();
+    FilteringPlugin::TraverseSwitchStmt(switchStmt);
+    switchStmtBody = prev;
+    return true;
+}
+
+bool Indentation::VisitCompoundStmt(CompoundStmt const* compoundStmt)
+{
+    if (ignoreLocation(compoundStmt))
+        return true;
+    // these are kind of free form
+    if (switchStmtBody == compoundStmt)
+        return true;
+
+    constexpr unsigned MAX = std::numeric_limits<unsigned>::max();
+    unsigned column = MAX;
+    Stmt const* firstStmt = nullptr;
+    unsigned curLine = MAX;
+    unsigned prevLine = MAX;
+    auto& SM = compiler.getSourceManager();
+    for (auto i = compoundStmt->body_begin(); i != compoundStmt->body_end(); ++i)
+    {
+        auto stmt = *i;
+
+        // these show up in macro expansions, not interesting
+        if (isa<NullStmt>(stmt))
+            continue;
+        // these are always weirdly indented
+        if (isa<LabelStmt>(stmt))
+            continue;
+
+        auto stmtLoc = compat::getBeginLoc(stmt);
+
+        StringRef macroName;
+        if (SM.isMacroArgExpansion(stmtLoc) || SM.isMacroBodyExpansion(stmtLoc))
+        {
+            macroName = Lexer::getImmediateMacroNameForDiagnostics(
+                stmtLoc, compiler.getSourceManager(), compiler.getLangOpts());
+            // CPPUNIT_TEST_SUITE/CPPUNIT_TEST/CPPUNIT_TEST_SUITE_END work together, so the one is indented inside the other
+            if (macroName == "CPPUNIT_TEST_SUITE")
+                continue;
+            // similar thing in dbaccess/
+            if (macroName == "DECL_PROP_IMPL")
+                continue;
+            // similar thing in forms/
+            if (macroName == "DECL_IFACE_PROP_IMPL" || macroName == "DECL_BOOL_PROP_IMPL")
+                continue;
+#if CLANG_VERSION >= 80000
+            stmtLoc = SM.getExpansionRange(stmtLoc).getBegin();
+#else
+            stmtLoc = SM.getExpansionRange(stmtLoc).first;
+#endif
+        }
+
+        // check for comment to the left of the statement
+        {
+            const char* p1 = SM.getCharacterData(stmtLoc);
+            --p1;
+            bool foundComment = false;
+            while (*p1 && *p1 != '\n')
+            {
+                if (*p1 == '/')
+                {
+                    foundComment = true;
+                    break;
+                }
+                --p1;
+            }
+            if (foundComment)
+                continue;
+        }
+
+        bool invalid1 = false;
+        bool invalid2 = false;
+        unsigned tmpColumn = SM.getPresumedColumnNumber(stmtLoc, &invalid1);
+        unsigned tmpLine = SM.getPresumedLineNumber(stmtLoc, &invalid2);
+        if (invalid1 || invalid2)
+            continue;
+        prevLine = curLine;
+        curLine = tmpLine;
+        if (column == MAX)
+        {
+            column = tmpColumn;
+            firstStmt = stmt;
+        }
+        else if (curLine == prevLine)
+        {
+            // ignore multiple statements on same line
+        }
+        else if (column != tmpColumn)
+        {
+            report(DiagnosticsEngine::Warning, "statement mis-aligned compared to neighbours %0",
+                   stmtLoc)
+                << macroName;
+            report(DiagnosticsEngine::Note, "measured against this one",
+                   compat::getBeginLoc(firstStmt));
+            //getParentStmt(compoundStmt)->dump();
+            //stmt->dump();
+        }
+    }
+    return true;
+}
+
+bool Indentation::VisitSwitchStmt(SwitchStmt const* switchStmt)
+{
+    if (ignoreLocation(switchStmt))
+        return true;
+
+    constexpr unsigned MAX = std::numeric_limits<unsigned>::max();
+    unsigned column = MAX;
+    Stmt const* firstStmt = nullptr;
+    unsigned curLine = MAX;
+    unsigned prevLine = MAX;
+    auto& SM = compiler.getSourceManager();
+    auto compoundStmt = dyn_cast<CompoundStmt>(switchStmt->getBody());
+    if (!compoundStmt)
+        return true;
+    for (auto i = compoundStmt->body_begin(); i != compoundStmt->body_end(); ++i)
+    {
+        Stmt const* caseStmt = dyn_cast<CaseStmt>(*i);
+        if (!caseStmt)
+            caseStmt = dyn_cast<DefaultStmt>(*i);
+        if (!caseStmt)
+            continue;
+
+        auto stmtLoc = compat::getBeginLoc(caseStmt);
+
+        bool invalid1 = false;
+        bool invalid2 = false;
+        unsigned tmpColumn = SM.getPresumedColumnNumber(stmtLoc, &invalid1);
+        unsigned tmpLine = SM.getPresumedLineNumber(stmtLoc, &invalid2);
+        if (invalid1 || invalid2)
+            continue;
+        prevLine = curLine;
+        curLine = tmpLine;
+        if (column == MAX)
+        {
+            column = tmpColumn;
+            firstStmt = caseStmt;
+        }
+        else if (curLine == prevLine)
+        {
+            // ignore multiple statements on same line
+        }
+        else if (column != tmpColumn)
+        {
+            // disable this for now, ends up touching some very large switch statemnts in sw/ and sc/
+            (void)firstStmt;
+            //            report(DiagnosticsEngine::Warning, "statement mis-aligned compared to neighbours",
+            //                   stmtLoc);
+            //            report(DiagnosticsEngine::Note, "measured against this one",
+            //                   compat::getBeginLoc(firstStmt));
+            //getParentStmt(compoundStmt)->dump();
+            //stmt->dump();
+        }
+    }
+    return true;
+}
+
+loplugin::Plugin::Registration<Indentation> X("indentation");
+
+} // namespace
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */