Delay loading of kallsyms file until it is needed

This is mostly done to enable a future patch that will load the
kallsyms file via it's build-id from the debug path.

Change-Id: Ic5c6ecd09dfdf7f8c42b13497f77bc6c43147cf8
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

3 files changed, 14 insertions, 8 deletions

diff --git a/app/perfkallsyms.h b/app/perfkallsyms.h
index 3fd16bc..efce043 100644
--- a/app/perfkallsyms.h
+++ b/app/perfkallsyms.h
@@ -41,6 +41,7 @@ class PerfKallsyms
 public:
     bool parseMapping(const QString &path);
     QString errorString() const { return m_errorString; }
+    bool isEmpty() const { return m_entries.isEmpty(); }
 
     PerfKallsymEntry findEntry(quint64 address) const;
 
diff --git a/app/perfunwind.cpp b/app/perfunwind.cpp
index 12ccfef..09d17ce 100644
--- a/app/perfunwind.cpp
+++ b/app/perfunwind.cpp
@@ -91,7 +91,8 @@ PerfUnwind::PerfUnwind(QIODevice *output, const QString &systemRoot, const QStri
                        int maxFrames) :
     m_output(output), m_architecture(PerfRegisterInfo::ARCH_INVALID), m_systemRoot(systemRoot),
     m_extraLibsPath(extraLibsPath), m_appPath(appPath), m_debugPath(debugPath),
-    m_maxEventBufferSize(maxEventBufferSize), m_eventBufferSize(0), m_lastFlushMaxTime(0)
+    m_kallsymsPath(kallsymsPath), m_maxEventBufferSize(maxEventBufferSize), m_eventBufferSize(0),
+    m_lastFlushMaxTime(0)
 {
     m_stats.enabled = printStats;
     m_currentUnwind.unwind = this;
@@ -114,11 +115,6 @@ PerfUnwind::PerfUnwind(QIODevice *output, const QString &systemRoot, const QStri
         qint32 dataStreamVersion = qToLittleEndian(QDataStream::Qt_DefaultCompiledVersion);
         output->write(reinterpret_cast<const char *>(&dataStreamVersion), sizeof(qint32));
     }
-
-    if (!m_kallsyms.parseMapping(kallsymsPath))
-        sendError(InvalidKallsyms,
-                  tr("Failed to parse kernel symbol mapping file \"%1\": %2")
-                    .arg(kallsymsPath, m_kallsyms.errorString()));
 }
 
 PerfUnwind::~PerfUnwind()
@@ -553,8 +549,14 @@ void PerfUnwind::resolveSymbol(int locationId, const PerfUnwind::Symbol &symbol)
     sendSymbol(locationId, symbol);
 }
 
-PerfKallsymEntry PerfUnwind::findKallsymEntry(quint64 address) const
+PerfKallsymEntry PerfUnwind::findKallsymEntry(quint64 address)
 {
+    if (m_kallsyms.isEmpty() && m_kallsyms.errorString().isEmpty()) {
+        if (!m_kallsyms.parseMapping(m_kallsymsPath))
+            sendError(InvalidKallsyms,
+                      tr("Failed to parse kernel symbol mapping file \"%1\": %2")
+                            .arg(m_kallsymsPath, m_kallsyms.errorString()));
+    }
     return m_kallsyms.findEntry(address);
 }
 
diff --git a/app/perfunwind.h b/app/perfunwind.h
index 209e863..740b6b8 100644
--- a/app/perfunwind.h
+++ b/app/perfunwind.h
@@ -140,7 +140,7 @@ public:
     bool hasSymbol(int locationId) const;
     void resolveSymbol(int locationId, const Symbol &symbol);
 
-    PerfKallsymEntry findKallsymEntry(quint64 address) const;
+    PerfKallsymEntry findKallsymEntry(quint64 address);
 
     enum ErrorCode {
         TimeOrderViolation = 1,
@@ -192,6 +192,9 @@ private:
     // Path to debug information, e.g. ~/.debug and /usr/local/debug
     QString m_debugPath;
 
+    // Path to kallsyms path
+    QString m_kallsymsPath;
+
     QList<PerfRecordSample> m_sampleBuffer;
     QList<PerfRecordMmap> m_mmapBuffer;
     QHash<quint32, PerfSymbolTable *> m_symbolTables;