Revert "Allow compiler plugins for online"

This reverts commit b39e627b.  The assumed (see
comment at <https://gerrit.libreoffice.org/#/c/46769/4/compilerplugins/clang/
plugin.cxx@633>) performance bottleneck of isSamePathname -> getAbsolutePath
does show up in Flamegraph inspections of LO builds.  But changing (non-member
function) isSamePathname to only call getAbsolutePath if (PluginHandlder member
function) isLOOLMode is true would need some code reorg, and Online development
doesn't seem to make too much actual use of the plugin, so conclusion on IRC was
to revert.

Change-Id: I0f04fdcc87087dac516630ed5e48361f5ea332ca
Reviewed-on: https://gerrit.libreoffice.org/51774Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

compilerplugins/clang/plugin.cxx

@@ -18,8 +18,6 @@
 #include <clang/Basic/FileManager.h>
 #include <clang/Lex/Lexer.h>
 
-#include <llvm/Support/Path.h>
-
 #include "pluginhandler.hxx"
 
 /*
@@ -653,20 +651,10 @@ bool hasPathnamePrefix(StringRef pathname, StringRef prefix)
         [](StringRef p, StringRef a) { return p.startswith(a); });
 }
 
-std::string getAbsolutePath(StringRef path)
-{
-    llvm::SmallString<1024> absPath(path);
-    llvm::sys::fs::make_absolute(absPath);
-    llvm::sys::path::remove_dots(absPath, true);
-    return absPath.str().str();
-}
-
 bool isSamePathname(StringRef pathname, StringRef other)
 {
-    std::string absPathname = getAbsolutePath(pathname);
-    std::string absOther = getAbsolutePath(other);
     return checkPathname(
-        absPathname, absOther, [](StringRef p, StringRef a) { return p == a; });
+        pathname, other, [](StringRef p, StringRef a) { return p == a; });
 }
 
 } // namespace

compilerplugins/clang/plugin.hxx

@@ -80,7 +80,6 @@ protected:
     bool isInUnoIncludeFile(const FunctionDecl*) const;
 
     bool isDebugMode() const { return handler.isDebugMode(); }
-    bool isLOOLMode() const { return handler.isLOOLMode(); }
 
     static bool isUnitTestMode();
 
@@ -230,9 +229,6 @@ void normalizeDotDotInFilePath(std::string&);
 // prefix may also contain backslashes:
 bool hasPathnamePrefix(StringRef pathname, StringRef prefix);
 
-// get the absolute path for a given path
-std::string getAbsolutePath(StringRef path);
-
 // Same as pathname == other, except on Windows, where pathname and other may
 // also contain backslashes:
 bool isSamePathname(StringRef pathname, StringRef other);

compilerplugins/clang/pluginhandler.cxx

@@ -18,7 +18,6 @@
 #include <clang/Frontend/CompilerInstance.h>
 #include <clang/Frontend/FrontendPluginRegistry.h>
 #include <clang/Lex/PPCallbacks.h>
-
 #include <stdio.h>
 
 #if defined _WIN32
@@ -117,8 +116,6 @@ void PluginHandler::handleOption( const std::string& option )
         unitTestMode = true;
     else if (option == "debug")
         debugMode = true;
-    else if ( option.substr(0, 15) == "lool-base-path=" )
-        loolBasePath = option.substr(15);
     else
         report( DiagnosticsEngine::Fatal, "unknown option %0" ) << option;
 }
@@ -196,7 +193,7 @@ bool PluginHandler::checkIgnoreLocation(SourceLocation loc)
     if( compiler.getSourceManager().isInSystemHeader( expansionLoc ))
         return true;
     const char* bufferName = compiler.getSourceManager().getPresumedLoc( expansionLoc ).getFilename();
-    if (bufferName == nullptr
+    if (bufferName == NULL
         || hasPathnamePrefix(bufferName, SRCDIR "/external/")
         || isSamePathname(bufferName, SRCDIR "/sdext/source/pdfimport/wrapper/keyword_list") )
             // workdir/CustomTarget/sdext/pdfimport/hash.cxx is generated from
@@ -225,11 +222,6 @@ bool PluginHandler::checkIgnoreLocation(SourceLocation loc)
         if (hasPathnamePrefix(s, WORKDIR))
             return true;
     }
-    if ( isLOOLMode() ) {
-        std::string absPath = getAbsolutePath(bufferName);
-        if ( StringRef(absPath).startswith(loolBasePath) )
-            return false;
-    }
     if( hasPathnamePrefix(bufferName, BUILDDIR)
         || hasPathnamePrefix(bufferName, SRCDIR) )
         return false; // ok
@@ -305,12 +297,6 @@ void PluginHandler::HandleTranslationUnit( ASTContext& context )
             pathWarning = "modified source in build dir : %0";
         else if( name.startswith(SRCDIR "/") )
             ; // ok
-        else if ( isLOOLMode() )
-        {
-            std::string absPath = getAbsolutePath(name);
-            if ( !StringRef(absPath).startswith(loolBasePath) )
-                bSkip = true;
-        }
         else
         {
             pathWarning = "modified source in unknown location, not modifying : %0";

compilerplugins/clang/pluginhandler.hxx

@@ -55,7 +55,6 @@ public:
             CompilerInstance& compiler, SourceLocation loc = SourceLocation());
     bool ignoreLocation(SourceLocation loc);
     bool isDebugMode() const { return debugMode; }
-    bool isLOOLMode() const { return !loolBasePath.empty(); }
     static bool isUnitTestMode();
     // If we overlap with a previous area we modified, we cannot perform this change
     // without corrupting the source
@@ -72,7 +71,6 @@ private:
     Rewriter rewriter;
     std::string scope;
     std::string warningsOnly;
-    std::string loolBasePath;
     bool warningsAsErrors;
     bool debugMode = false;
     std::vector<std::pair<char const*, char const*>> mvModifiedRanges;