add support for d symbol demangling

I added a system that simplifies adding new demanglers and provides a
fast path when demangling symbols

Change-Id: Ie5ca43632b53e41c0a4214772193af09ca4593cc
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

8 files changed, 163 insertions, 30 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d379096..3038294 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,5 +15,12 @@ set_package_properties(LibRustcDemangle PROPERTIES
         URL "https://github.com/alexcrichton/rustc-demangle"
         TYPE RUNTIME)
 
+find_package(LibDDemangle)
+set_package_properties(LibDDemangle PROPERTIES
+        DESCRIPTION "Demangling for D symbols, written in D."
+        PURPOSE "Demangling of D symbols"
+        URL "https://github.com/lievenhey/d_demangler"
+        TYPE RUNTIME)
+
 add_subdirectory(app)
 add_subdirectory(tests)
diff --git a/app/CMakeLists.txt b/app/CMakeLists.txt
index 6efe84b..4107a11 100644
--- a/app/CMakeLists.txt
+++ b/app/CMakeLists.txt
@@ -22,6 +22,7 @@ add_qtc_library(perfparser_lib STATIC
     perftracingdata.cpp perftracingdata.h
     perfdwarfdiecache.cpp perfdwarfdiecache.h
     perfeucompat.h
+    demangler.cpp demangler.h
 )
 
 if (Zstd_FOUND)
diff --git a/app/demangler.cpp b/app/demangler.cpp
new file mode 100644
index 0000000..ce9d630
--- /dev/null
+++ b/app/demangler.cpp
@@ -0,0 +1,79 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Lieven Hey <lieven.hey@kdab.com>
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Enterprise Perf Profiler Add-on.
+**
+** GNU General Public License Usage
+** This file may be used under the terms of the GNU General Public License
+** version 3 as published by the Free Software Foundation and appearing in
+** the file LICENSE.GPLv3 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.html.
+**
+** If you have questions regarding the use of this file, please use
+** contact form at http://www.qt.io/contact-us
+**
+****************************************************************************/
+
+#include "demangler.h"
+
+#include <QLibrary>
+#include <QDebug>
+
+/* Demangler specification
+ * int demangler(const char* mangledSymbol, char* demangledBuffer, size_t bufferSize)
+ *
+ * size_t is platform dependent (4 bytes on 32 bit, 8 bytes on 64 bit)
+ * */
+
+namespace {
+bool startsWith(const char* string, const QByteArray& prefix) {
+    return strcmp(string, prefix.constData()) == 0;
+}
+}
+
+Demangler::Demangler()
+{
+    loadDemangleLib(QStringLiteral("rustc_demangle"), "rustc_demangle", QByteArrayLiteral("_R"));
+    loadDemangleLib(QStringLiteral("d_demangle"), "demangle_symbol", QByteArrayLiteral("_D"));
+}
+
+bool Demangler::demangle(const char *mangledSymbol, char *demangleBuffer, size_t demangleBufferLength)
+{
+    // fast path, some languages (like rust since 1.37 or d) share a common prefix
+    // try these first
+    for (const auto& demangler : m_demanglers) {
+        if (startsWith(mangledSymbol, demangler.prefix)) {
+            if (demangler.demangler(mangledSymbol, demangleBuffer, demangleBufferLength)) {
+                return true;
+            }
+        }
+    }
+
+    for (const auto& demangler : m_demanglers) {
+        if (demangler.demangler(mangledSymbol, demangleBuffer, demangleBufferLength)) {
+            return true;
+        }
+    }
+    return false;
+}
+
+void Demangler::loadDemangleLib(const QString &name, const char* function, const QByteArray& prefix)
+{
+    QLibrary lib(name);
+    if (!lib.load()) {
+        qDebug() << QStringLiteral("failed to load %1 library").arg(name)
+                 << lib.errorString();
+        return;
+    }
+    const auto rawSymbol = lib.resolve(function);
+    if (!rawSymbol) {
+        qDebug() << QStringLiteral("failed to resolve %1 function in library").arg(function)
+                 << lib.fileName() << lib.errorString();
+        return;
+    }
+
+    m_demanglers.push_back({prefix, reinterpret_cast<Demangler::demangler_t>(rawSymbol)});
+}
diff --git a/app/demangler.h b/app/demangler.h
new file mode 100644
index 0000000..edb1244
--- /dev/null
+++ b/app/demangler.h
@@ -0,0 +1,44 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Lieven Hey <lieven.hey@kdab.com>
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Enterprise Perf Profiler Add-on.
+**
+** GNU General Public License Usage
+** This file may be used under the terms of the GNU General Public License
+** version 3 as published by the Free Software Foundation and appearing in
+** the file LICENSE.GPLv3 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.html.
+**
+** If you have questions regarding the use of this file, please use
+** contact form at http://www.qt.io/contact-us
+**
+****************************************************************************/
+
+#ifndef DEMANGLER_H
+#define DEMANGLER_H
+
+#include <QVector>
+
+class Demangler
+{
+public:
+    Demangler();
+
+    bool demangle(const char* mangledSymbol, char* demangleBuffer, size_t demangleBufferLength);
+
+private:
+    void loadDemangleLib(const QString& name, const char* function, const QByteArray& prefix);
+
+    using demangler_t = int (*) (const char*, char *, size_t);
+    struct DemangleInfo {
+        QByteArray prefix;
+        demangler_t demangler;
+    };
+
+    QVector<DemangleInfo> m_demanglers;
+};
+
+#endif // DEMANGLER_H
diff --git a/app/perfdwarfdiecache.cpp b/app/perfdwarfdiecache.cpp
index dfc6f90..6f9243f 100644
--- a/app/perfdwarfdiecache.cpp
+++ b/app/perfdwarfdiecache.cpp
@@ -24,35 +24,9 @@
 
 #include <dwarf.h>
 
-#include <QLibrary>
-#include <QDebug>
+#include "demangler.h"
 
 namespace {
-bool rustc_demangle(const char *symbol, char *buffer, size_t bufferSize)
-{
-    using demangler_t = int (*) (const char*, char *, size_t);
-    static const auto demangler = []() -> demangler_t {
-        QLibrary lib(QStringLiteral("rustc_demangle"));
-        if (!lib.load()) {
-            qDebug() << "failed to load rustc_demangle library, rust demangling support is not available."
-                     << lib.errorString();
-            return nullptr;
-        }
-        const auto rawSymbol = lib.resolve("rustc_demangle");
-        if (!rawSymbol) {
-            qDebug() << "failed to resolve rustc_demangle function in library"
-                     << lib.fileName() << lib.errorString();
-            return nullptr;
-        }
-        return reinterpret_cast<demangler_t>(rawSymbol);
-    }();
-
-    if (demangler)
-        return demangler(symbol, buffer, bufferSize);
-    else
-        return false;
-}
-
 enum class WalkResult
 {
     Recurse,
@@ -252,9 +226,11 @@ QByteArray demangle(const QByteArray &mangledName)
     } else {
         static size_t demangleBufferLength = 1024;
         static char *demangleBuffer = reinterpret_cast<char *>(eu_compat_malloc(demangleBufferLength));
+        static Demangler demangler;
 
-        if (rustc_demangle(mangledName.constData(), demangleBuffer, demangleBufferLength))
+        if (demangler.demangle(mangledName, demangleBuffer, demangleBufferLength)) {
             return demangleBuffer;
+        }
 
         // Require GNU v3 ABI by the "_Z" prefix.
         if (mangledName[0] == '_' && mangledName[1] == 'Z') {
diff --git a/cmake/FindLibDDemangle.cmake b/cmake/FindLibDDemangle.cmake
new file mode 100644
index 0000000..04f0ecc
--- /dev/null
+++ b/cmake/FindLibDDemangle.cmake
@@ -0,0 +1,22 @@
+if (LIBD_DEMANGLE_LIBRARIES)
+    set (LibDDemangle_FIND_QUIETLY TRUE)
+endif()
+
+find_library(LIBD_DEMANGLE_LIBRARIES
+    NAMES
+      d_demangle
+    PATHS
+      /usr/lib
+      /usr/local/lib
+      /opt/local/lib
+      /sw/lib
+      ENV LIBRARY_PATH
+      ENV LD_LIBRARY_PATH)
+
+include (FindPackageHandleStandardArgs)
+
+# handle the QUIETLY and REQUIRED arguments and set LIBRUSTC_DEMANGLE_FOUND to TRUE if all listed variables are TRUE
+find_package_handle_standard_args(LibDDemangle DEFAULT_MSG
+    LIBD_DEMANGLE_LIBRARIES)
+
+mark_as_advanced(LIBD_DEMANGLE_LIBRARIES)
diff --git a/tests/auto/perfdata/perfdata.pro b/tests/auto/perfdata/perfdata.pro
index 145ed79..2e32aa6 100644
--- a/tests/auto/perfdata/perfdata.pro
+++ b/tests/auto/perfdata/perfdata.pro
@@ -24,7 +24,8 @@ SOURCES += \
     ../../../app/perfsymboltable.cpp \
     ../../../app/perftracingdata.cpp \
     ../../../app/perfunwind.cpp \
-    ../../../app/perfdwarfdiecache.cpp
+    ../../../app/perfdwarfdiecache.cpp \
+    ../../../app/demangle.cpp
 
 HEADERS += \
     ../../../app/perfaddresscache.h \
@@ -39,7 +40,8 @@ HEADERS += \
     ../../../app/perfsymboltable.h \
     ../../../app/perftracingdata.h \
     ../../../app/perfunwind.h \
-    ../../../app/perfdwarfdiecache.h
+    ../../../app/perfdwarfdiecache.h \
+    ../../../app/demangle.h
 
 RESOURCES += \
     perfdata.qrc
diff --git a/tests/auto/perfdata/perfdata.qbs b/tests/auto/perfdata/perfdata.qbs
index ef9bb3d..033a0a3 100644
--- a/tests/auto/perfdata/perfdata.qbs
+++ b/tests/auto/perfdata/perfdata.qbs
@@ -37,5 +37,7 @@ QtcAutotest {
         "../../../app/perftracingdata.h",
         "../../../app/perfunwind.cpp",
         "../../../app/perfunwind.h",
+        "../../../app/demangle.cpp",
+        "../../../app/demangle.h"
     ]
 }