Add support for sampled PC profiling to FullCPU.

Simple text list of symbol (or address) and count
will be dumped to m5prof.<cpu-name> if the cpu's
pc_sample_interval param is set.

SConscript:
    Add cpu/full_cpu/pc_sample_profile.cc
base/callback.hh:
    Add a comment about MakeCallback.
    Fix type in another comment.
base/loader/symtab.cc:
    Revamp findNearestSymbol() to provide addresses of both
    nearest symbols (preceding and following) as well as
    string for former.

    Move global definition of debugSymbolTable here too.
base/loader/symtab.hh:
    Revamp findNearestSymbol() to provide addresses of both
    nearest symbols (preceding and following) as well as
    string for former.

    Move global declaration of debugSymbolTable here too.
cpu/exetrace.cc:
    Use new findNearestSymbol() interface for trace symbols.
kern/linux/linux_system.cc:
sim/system.cc:
    Remove extern of debugSymbolTable (now in symtab.hh)
sim/process.cc:
    Initialize debugSymbolTable if binary has a symbol table.

--HG--
extra : convert_revision : 0b5393dc39c40ac88c953684708f1125da550671

2 files changed, 13 insertions, 2 deletions

diff --git a/sim/process.cc b/sim/process.cc
index 98db1f2e0..bd1a2d8fd 100644
--- a/sim/process.cc
+++ b/sim/process.cc
@@ -34,6 +34,7 @@
 
 #include "base/intmath.hh"
 #include "base/loader/object_file.hh"
+#include "base/loader/symtab.hh"
 #include "base/statistics.hh"
 #include "cpu/exec_context.hh"
 #include "cpu/full_cpu/smt.hh"
@@ -263,6 +264,18 @@ LiveProcess::LiveProcess(const string &name, ObjectFile *objFile,
     // load object file into target memory
     objFile->loadSections(memory);
 
+    // load up symbols, if any... these may be used for debugging or
+    // profiling.
+    if (!debugSymbolTable) {
+        debugSymbolTable = new SymbolTable();
+        if (!objFile->loadGlobalSymbols(debugSymbolTable) ||
+            !objFile->loadLocalSymbols(debugSymbolTable)) {
+            // didn't load any symbols
+            delete debugSymbolTable;
+            debugSymbolTable = NULL;
+        }
+    }
+
     // Set up stack.  On Alpha, stack goes below text section.  This
     // code should get moved to some architecture-specific spot.
     stack_base = text_base - (409600+4096);
diff --git a/sim/system.cc b/sim/system.cc
index 1b1a145c6..c6a65f9d9 100644
--- a/sim/system.cc
+++ b/sim/system.cc
@@ -44,8 +44,6 @@ vector<System *> System::systemList;
 
 int System::numSystemsRunning = 0;
 
-extern SymbolTable *debugSymbolTable;
-
 System::System(Params *p)
     : SimObject(p->name), memctrl(p->memctrl), physmem(p->physmem),
       init_param(p->init_param), params(p)