Mon Aug 13 14:09:54 PDT 2012

Author: johnny
Date: Mon Aug 13 16:09:54 2012
New Revision: 161785

URL: http://llvm.org/viewvc/llvm-project?rev=161785&view=rev
Log:
rdar://problem/12007576

Record the snapshot of our watched value when the watchpoint is set or hit.
And report the old/new values when watchpoint is triggered.  Add some test scenarios.

Modified:
    lldb/trunk/include/lldb/Breakpoint/Watchpoint.h
    lldb/trunk/lldb.xcodeproj/project.pbxproj
    lldb/trunk/source/Breakpoint/Watchpoint.cpp
    lldb/trunk/source/Breakpoint/WatchpointOptions.cpp
    lldb/trunk/source/Commands/CommandObjectWatchpoint.cpp
    lldb/trunk/source/Target/StopInfo.cpp
    lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/TestWatchpointCommandLLDB.py
    lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/TestWatchpointCommandPython.py
    lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/main.cpp

Modified: lldb/trunk/include/lldb/Breakpoint/Watchpoint.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Breakpoint/Watchpoint.h?rev=161785&r1=161784&r2=161785&view=diff
==============================================================================

--- lldb/trunk/include/lldb/Breakpoint/Watchpoint.h (original)
+++ lldb/trunk/include/lldb/Breakpoint/Watchpoint.h Mon Aug 13 16:09:54 2012
@@ -53,10 +53,25 @@
     uint32_t    GetIgnoreCount () const;
     void        SetIgnoreCount (uint32_t n);
     void        SetWatchpointType (uint32_t type);
-    void        SetDeclInfo (std::string &str);
-    void        SetWatchSpec (std::string &str);
+    void        SetDeclInfo (const std::string &str);
+    std::string GetWatchSpec();
+    void        SetWatchSpec (const std::string &str);
+
+    // Snapshot management interface.
+    bool        IsWatchVariable() const;
+    void        SetWatchVariable(bool val);
+    std::string GetOldSnapshot() const;
+    void        SetOldSnapshot (const std::string &str);
+    std::string GetNewSnapshot() const;
+    void        SetNewSnapshot (const std::string &str);
+    uint64_t    GetOldSnapshotVal() const;
+    void        SetOldSnapshotVal (uint64_t val);
+    uint64_t    GetNewSnapshotVal() const;
+    void        SetNewSnapshotVal (uint64_t val);
+
     void        GetDescription (Stream *s, lldb::DescriptionLevel level);
     void        Dump (Stream *s) const;
+    void        DumpSnapshots (const char * prefix, Stream *s) const;
     void        DumpWithLevel (Stream *s, lldb::DescriptionLevel description_level) const;
     Target      &GetTarget() { return *m_target; }
     const Error &GetError() { return m_error; }
@@ -136,19 +151,23 @@
     friend class WatchpointList;
 
     void        SetTarget(Target *target_ptr) { m_target = target_ptr; }
-    std::string GetWatchSpec() { return m_watch_spec_str; }
     void        ResetHitCount() { m_hit_count = 0; }
 
     Target      *m_target;
     bool        m_enabled;             // Is this watchpoint enabled
     bool        m_is_hardware;         // Is this a hardware watchpoint
+    bool        m_is_watch_variable;   // True if set via 'watchpoint set variable'.
     uint32_t    m_watch_read:1,        // 1 if we stop when the watched data is read from
                 m_watch_write:1,       // 1 if we stop when the watched data is written to
                 m_watch_was_read:1,    // Set to 1 when watchpoint is hit for a read access
                 m_watch_was_written:1; // Set to 1 when watchpoint is hit for a write access
     uint32_t    m_ignore_count;        // Number of times to ignore this breakpoint
     std::string m_decl_str;            // Declaration information, if any.
-    std::string m_watch_spec_str;      // Spec for the watchpoint (for future use).
+    std::string m_watch_spec_str;      // Spec for the watchpoint.
+    std::string m_snapshot_old_str;    // Old snapshot for the watchpoint value as by ValueObject::DumpValueObject().
+    std::string m_snapshot_new_str;    // New Snapshot for the watchpoint value as by ValueObject::DumpValueObject().
+    uint64_t    m_snapshot_old_val;    // Old snapshot for the watchpoint bytes.
+    uint64_t    m_snapshot_new_val;    // New Snapshot for the watchpoint bytes.
     Error       m_error;               // An error object describing errors associated with this watchpoint.
     WatchpointOptions m_options;       // Settable watchpoint options, which is a delegate to handle
                                        // the callback machinery.

Modified: lldb/trunk/lldb.xcodeproj/project.pbxproj
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/lldb.xcodeproj/project.pbxproj?rev=161785&r1=161784&r2=161785&view=diff
==============================================================================
--- lldb/trunk/lldb.xcodeproj/project.pbxproj (original)
+++ lldb/trunk/lldb.xcodeproj/project.pbxproj Mon Aug 13 16:09:54 2012
@@ -4407,7 +4407,7 @@
 				HEADER_SEARCH_PATHS = /usr/include/libxml2;
 				LD_DYLIB_INSTALL_NAME = "$(DEVELOPER_DIR)/Library/PrivateFrameworks/LLDB.framework/Resources/lldb-core.a";
 				MACH_O_TYPE = staticlib;
-				MACOSX_DEPLOYMENT_TARGET = "10.7";
+				MACOSX_DEPLOYMENT_TARGET = 10.7;
 				OTHER_CPLUSPLUSFLAGS = (
 					"-fno-rtti",
 					"-Wglobal-constructors",
@@ -4438,7 +4438,7 @@
 				HEADER_SEARCH_PATHS = /usr/include/libxml2;
 				LD_DYLIB_INSTALL_NAME = "$(DEVELOPER_DIR)/Library/PrivateFrameworks/LLDB.framework/Resources/lldb-core.a";
 				MACH_O_TYPE = staticlib;
-				MACOSX_DEPLOYMENT_TARGET = "10.7";
+				MACOSX_DEPLOYMENT_TARGET = 10.7;
 				OTHER_CPLUSPLUSFLAGS = (
 					"-fno-rtti",
 					"-Wglobal-constructors",
@@ -4469,7 +4469,7 @@
 				HEADER_SEARCH_PATHS = /usr/include/libxml2;
 				LD_DYLIB_INSTALL_NAME = "$(DEVELOPER_DIR)/Library/PrivateFrameworks/LLDB.framework/Resources/lldb-core.a";
 				MACH_O_TYPE = staticlib;
-				MACOSX_DEPLOYMENT_TARGET = "10.7";
+				MACOSX_DEPLOYMENT_TARGET = 10.7;
 				OTHER_CPLUSPLUSFLAGS = (
 					"-fno-rtti",
 					"-Wglobal-constructors",

Modified: lldb/trunk/source/Breakpoint/Watchpoint.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Breakpoint/Watchpoint.cpp?rev=161785&r1=161784&r2=161785&view=diff
==============================================================================
--- lldb/trunk/source/Breakpoint/Watchpoint.cpp (original)
+++ lldb/trunk/source/Breakpoint/Watchpoint.cpp Mon Aug 13 16:09:54 2012
@@ -28,6 +28,7 @@
     m_target(NULL),
     m_enabled(false),
     m_is_hardware(hardware),
+    m_is_watch_variable(false),
     m_watch_read(0),
     m_watch_write(0),
     m_watch_was_read(0),
@@ -35,6 +36,10 @@
     m_ignore_count(0),
     m_decl_str(),
     m_watch_spec_str(),
+    m_snapshot_old_str(),
+    m_snapshot_new_str(),
+    m_snapshot_old_val(0),
+    m_snapshot_new_val(0),
     m_error(),
     m_options ()
 {
@@ -70,19 +75,79 @@
 }
 
 void
-Watchpoint::SetDeclInfo (std::string &str)
+Watchpoint::SetDeclInfo (const std::string &str)
 {
     m_decl_str = str;
     return;
 }
 
+std::string
+Watchpoint::GetWatchSpec()
+{
+    return m_watch_spec_str;
+}
+
 void
-Watchpoint::SetWatchSpec (std::string &str)
+Watchpoint::SetWatchSpec (const std::string &str)
 {
     m_watch_spec_str = str;
     return;
 }
 
+std::string
+Watchpoint::GetOldSnapshot() const
+{
+    return m_snapshot_old_str;
+}
+
+void
+Watchpoint::SetOldSnapshot (const std::string &str)
+{
+    m_snapshot_old_str = str;
+    return;
+}
+
+std::string
+Watchpoint::GetNewSnapshot() const
+{
+    return m_snapshot_new_str;
+}
+
+void
+Watchpoint::SetNewSnapshot (const std::string &str)
+{
+    m_snapshot_old_str = m_snapshot_new_str;
+    m_snapshot_new_str = str;
+    return;
+}
+
+uint64_t
+Watchpoint::GetOldSnapshotVal() const
+{
+    return m_snapshot_old_val;
+}
+
+void
+Watchpoint::SetOldSnapshotVal (uint64_t val)
+{
+    m_snapshot_old_val = val;
+    return;
+}
+
+uint64_t
+Watchpoint::GetNewSnapshotVal() const
+{
+    return m_snapshot_new_val;
+}
+
+void
+Watchpoint::SetNewSnapshotVal (uint64_t val)
+{
+    m_snapshot_old_val = m_snapshot_new_val;
+    m_snapshot_new_val = val;
+    return;
+}
+
 // Override default impl of StoppointLocation::IsHardware() since m_is_hardware
 // member field is more accurate.
 bool
@@ -91,6 +156,18 @@
     return m_is_hardware;
 }
 
+bool
+Watchpoint::IsWatchVariable() const
+{
+    return m_is_watch_variable;
+}
+
+void
+Watchpoint::SetWatchVariable(bool val)
+{
+    m_is_watch_variable = val;
+}
+
 // RETURNS - true if we should stop at this breakpoint, false if we
 // should continue.
 
@@ -122,6 +199,24 @@
 }
 
 void
+Watchpoint::DumpSnapshots(const char *prefix, Stream *s) const
+{
+    if (IsWatchVariable())
+    {
+        if (!m_snapshot_old_str.empty())
+            s->Printf("\n%swatchpoint old value:\n\t%s", prefix, m_snapshot_old_str.c_str());
+        if (!m_snapshot_new_str.empty())
+            s->Printf("\n%swatchpoint new value:\n\t%s", prefix, m_snapshot_new_str.c_str());
+    }
+    else
+    {
+        uint32_t num_hex_digits = GetByteSize() * 2;
+        s->Printf("\n%swatchpoint old value:0x%0*.*llx", prefix, num_hex_digits, num_hex_digits, m_snapshot_old_val);
+        s->Printf("\n%swatchpoint new value:0x%0*.*llx", prefix, num_hex_digits, num_hex_digits, m_snapshot_new_val);
+    }
+}
+
+void
 Watchpoint::DumpWithLevel(Stream *s, lldb::DescriptionLevel description_level) const
 {
     if (s == NULL)
@@ -142,7 +237,11 @@
         if (!m_decl_str.empty())
             s->Printf("\n    declare @ '%s'", m_decl_str.c_str());
         if (!m_watch_spec_str.empty())
-            s->Printf("\n    static watchpoint spec = '%s'", m_watch_spec_str.c_str());
+            s->Printf("\n    watchpoint spec = '%s'", m_watch_spec_str.c_str());
+
+        // Dump the snapshots we have taken.
+        DumpSnapshots("   ", s);
+
         if (GetConditionText())
             s->Printf("\n    condition = '%s'", GetConditionText());
         m_options.GetCallbackDescription(s, description_level);

Modified: lldb/trunk/source/Breakpoint/WatchpointOptions.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Breakpoint/WatchpointOptions.cpp?rev=161785&r1=161784&r2=161785&view=diff
==============================================================================
--- lldb/trunk/source/Breakpoint/WatchpointOptions.cpp (original)
+++ lldb/trunk/source/Breakpoint/WatchpointOptions.cpp Mon Aug 13 16:09:54 2012
@@ -168,11 +168,8 @@
 {
     if (m_callback_baton_sp.get())
     {
-        if (level != eDescriptionLevelBrief)
-        {
-            s->EOL();
-            m_callback_baton_sp->GetDescription (s, level);
-        }
+        s->EOL();
+        m_callback_baton_sp->GetDescription (s, level);
     }
 }
 void
@@ -222,7 +219,7 @@
     }
     
     s->IndentMore ();
-    s->Indent("Watchpoint commands:\n");
+    s->Indent("watchpoint commands:\n");
     
     s->IndentMore ();
     if (data && data->user_source.GetSize() > 0)

Modified: lldb/trunk/source/Commands/CommandObjectWatchpoint.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Commands/CommandObjectWatchpoint.cpp?rev=161785&r1=161784&r2=161785&view=diff
==============================================================================
--- lldb/trunk/source/Commands/CommandObjectWatchpoint.cpp (original)
+++ lldb/trunk/source/Commands/CommandObjectWatchpoint.cpp Mon Aug 13 16:09:54 2012
@@ -1047,6 +1047,8 @@
         error.Clear();
         Watchpoint *wp = target->CreateWatchpoint(addr, size, watch_type, error).get();
         if (wp) {
+            wp->SetWatchSpec(command.GetArgumentAtIndex(0));
+            wp->SetWatchVariable(true);
             if (var_sp && var_sp->GetDeclaration().GetFile()) {
                 StreamString ss;
                 // True to show fullpath for declaration file.
@@ -1054,13 +1056,15 @@
                 wp->SetDeclInfo(ss.GetString());
             }
             StreamString ss;
+            ValueObject::DumpValueObject(ss, valobj_sp.get());
+            wp->SetNewSnapshot(ss.GetString());
             output_stream.Printf("Watchpoint created: ");
             wp->GetDescription(&output_stream, lldb::eDescriptionLevelFull);
             output_stream.EOL();
             result.SetStatus(eReturnStatusSuccessFinishResult);
         } else {
-            result.AppendErrorWithFormat("Watchpoint creation failed (addr=0x%llx, size=%lu).\n",
-                                         addr, size);
+            result.AppendErrorWithFormat("Watchpoint creation failed (addr=0x%llx, size=%lu, variable expression='%s').\n",
+                                         addr, size, command.GetArgumentAtIndex(0));
             if (error.AsCString(NULL))
                 result.AppendError(error.AsCString());
             result.SetStatus(eReturnStatusFailed);
@@ -1238,8 +1242,12 @@
                 var_sp->GetDeclaration().DumpStopContext(&ss, true);
                 wp->SetDeclInfo(ss.GetString());
             }
-            StreamString ss;
             output_stream.Printf("Watchpoint created: ");
+            uint64_t val = target->GetProcessSP()->ReadUnsignedIntegerFromMemory(addr, size, 0, error);
+            if (error.Success())
+                wp->SetNewSnapshotVal(val);
+            else
+                output_stream.Printf("watchpoint snapshot failed: %s", error.AsCString());
             wp->GetDescription(&output_stream, lldb::eDescriptionLevelFull);
             output_stream.EOL();
             result.SetStatus(eReturnStatusSuccessFinishResult);

Modified: lldb/trunk/source/Target/StopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Target/StopInfo.cpp?rev=161785&r1=161784&r2=161785&view=diff
==============================================================================
--- lldb/trunk/source/Target/StopInfo.cpp (original)
+++ lldb/trunk/source/Target/StopInfo.cpp Mon Aug 13 16:09:54 2012
@@ -451,7 +451,7 @@
     virtual void
     PerformAction (Event *event_ptr)
     {
-        LogSP log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_BREAKPOINTS);
+        LogSP log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_WATCHPOINTS);
         // We're going to calculate if we should stop or not in some way during the course of
         // this code.  Also by default we're going to stop, so set that here.
         m_should_stop = true;
@@ -461,11 +461,11 @@
         if (wp_sp)
         {
             ExecutionContext exe_ctx (m_thread.GetStackFrameAtIndex(0));
+            Process* process = exe_ctx.GetProcessPtr();
             {
                 // check if this process is running on an architecture where watchpoints trigger
 				// before the associated instruction runs. if so, disable the WP, single-step and then
 				// re-enable the watchpoint
-                Process* process = exe_ctx.GetProcessPtr();
                 if (process)
                 {
                     uint32_t num; bool wp_triggers_after;
@@ -491,7 +491,62 @@
                     }
                 }
             }
-            StoppointCallbackContext context (event_ptr, exe_ctx, false);
+
+            // Record the snapshot of our watchpoint.
+            VariableSP var_sp;
+            ValueObjectSP valobj_sp;        
+            StackFrame *frame = exe_ctx.GetFramePtr();
+            if (frame)
+            {
+                if (!wp_sp->IsWatchVariable())
+                {
+                    assert (process);
+                    Error error;
+                    uint64_t val = process->ReadUnsignedIntegerFromMemory(wp_sp->GetLoadAddress(),
+                                                                          wp_sp->GetByteSize(),
+                                                                          0,
+                                                                          error);
+                    if (log)
+                    {
+                        if (error.Success())
+                            log->Printf("Watchpoint snapshot val taken: 0x%llx\n", val);
+                        else
+                            log->Printf("Watchpoint snapshot val taking failed.\n");
+                    }                        
+                    wp_sp->SetNewSnapshotVal(val);
+                }
+                else if (!wp_sp->GetWatchSpec().empty())
+                {
+                    // Things have checked out ok...
+                    Error error;
+                    uint32_t expr_path_options = StackFrame::eExpressionPathOptionCheckPtrVsMember |
+                                                 StackFrame::eExpressionPathOptionsAllowDirectIVarAccess;
+                    valobj_sp = frame->GetValueForVariableExpressionPath (wp_sp->GetWatchSpec().c_str(), 
+                                                                          eNoDynamicValues, 
+                                                                          expr_path_options,
+                                                                          var_sp,
+                                                                          error);
+                    if (valobj_sp)
+                    {
+                        // We're in business.
+                        StreamString ss;
+                        ValueObject::DumpValueObject(ss, valobj_sp.get());
+                        wp_sp->SetNewSnapshot(ss.GetString());
+                    }
+                    else
+                        wp_sp->SetNewSnapshot("snapshot attempt failed.");
+
+                    if (log)
+                        log->Printf("Watchpoint snapshot taken: '%s'\n", wp_sp->GetNewSnapshot().c_str());
+                }
+
+                // Now dump the snapshots we have taken.
+                Debugger &debugger = exe_ctx.GetTargetRef().GetDebugger();
+                StreamSP output_sp = debugger.GetAsyncOutputStream ();
+                wp_sp->DumpSnapshots("!!! ", output_sp.get());
+                //output_sp->EOL();
+                output_sp->Flush();
+            }
 
             if (m_should_stop && wp_sp->GetConditionText() != NULL)
             {
@@ -564,6 +619,7 @@
             // If the condition says to stop, we run the callback to further decide whether to stop.
             if (m_should_stop)
             {
+                StoppointCallbackContext context (event_ptr, exe_ctx, false);
                 bool stop_requested = wp_sp->InvokeCallback (&context);
                 // Also make sure that the callback hasn't continued the target.  
                 // If it did, when we'll set m_should_stop to false and get out of here.

Modified: lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/TestWatchpointCommandLLDB.py
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/TestWatchpointCommandLLDB.py?rev=161785&r1=161784&r2=161785&view=diff
==============================================================================
--- lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/TestWatchpointCommandLLDB.py (original)
+++ lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/TestWatchpointCommandLLDB.py Mon Aug 13 16:09:54 2012
@@ -63,11 +63,11 @@
             substrs = ['Watchpoint created', 'size = 4', 'type = w',
                        '%s:%d' % (self.source, self.decl)])
 
-        self.runCmd('watchpoint command add 1 -o "expr -- global = 777"')
+        self.runCmd('watchpoint command add 1 -o "expr -- cookie = 777"')
 
         # List the watchpoint command we just added.
         self.expect("watchpoint command list 1",
-            substrs = ['expr -- global = 777'])
+            substrs = ['expr -- cookie = 777'])
 
         # Use the '-v' option to do verbose listing of the watchpoint.
         # The hit count should be 0 initially.
@@ -81,9 +81,14 @@
         self.expect("thread backtrace", STOPPED_DUE_TO_WATCHPOINT,
             substrs = ['stop reason = watchpoint'])
 
-        # The watchpoint command "forced" our global variable to become 777.
-        self.expect("frame variable -g global",
-            substrs = ['(int32_t)', 'global = 777'])
+        # Check that the watchpoint snapshoting mechanism is working.
+        self.expect("watchpoint list -v",
+            substrs = ['watchpoint old value:', 'global = 0',
+                       'watchpoint new value:', 'global = 1'])
+
+        # The watchpoint command "forced" our global variable 'cookie' to become 777.
+        self.expect("frame variable -g cookie",
+            substrs = ['(int32_t)', 'cookie = 777'])
 
 
 if __name__ == '__main__':

Modified: lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/TestWatchpointCommandPython.py
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/TestWatchpointCommandPython.py?rev=161785&r1=161784&r2=161785&view=diff
==============================================================================
--- lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/TestWatchpointCommandPython.py (original)
+++ lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/TestWatchpointCommandPython.py Mon Aug 13 16:09:54 2012
@@ -63,11 +63,11 @@
             substrs = ['Watchpoint created', 'size = 4', 'type = w',
                        '%s:%d' % (self.source, self.decl)])
 
-        self.runCmd('watchpoint command add -s python 1 -o \'frame.EvaluateExpression("global = 777")\'')
+        self.runCmd('watchpoint command add -s python 1 -o \'frame.EvaluateExpression("cookie = 777")\'')
 
         # List the watchpoint command we just added.
         self.expect("watchpoint command list 1",
-            substrs = ['frame.EvaluateExpression', 'global = 777'])
+            substrs = ['frame.EvaluateExpression', 'cookie = 777'])
 
         # Use the '-v' option to do verbose listing of the watchpoint.
         # The hit count should be 0 initially.
@@ -81,9 +81,14 @@
         self.expect("thread backtrace", STOPPED_DUE_TO_WATCHPOINT,
             substrs = ['stop reason = watchpoint'])
 
-        # The watchpoint command "forced" our global variable to become 777.
-        self.expect("frame variable -g global",
-            substrs = ['(int32_t)', 'global = 777'])
+        # Check that the watchpoint snapshoting mechanism is working.
+        self.expect("watchpoint list -v",
+            substrs = ['watchpoint old value:', 'global = 0',
+                       'watchpoint new value:', 'global = 1'])
+
+        # The watchpoint command "forced" our global variable 'cookie' to become 777.
+        self.expect("frame variable -g cookie",
+            substrs = ['(int32_t)', 'cookie = 777'])
 
 
 if __name__ == '__main__':

Modified: lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/main.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/main.cpp?rev=161785&r1=161784&r2=161785&view=diff
==============================================================================
--- lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/main.cpp (original)
+++ lldb/trunk/test/functionalities/watchpoint/watchpoint_commands/command/main.cpp Mon Aug 13 16:09:54 2012
@@ -10,6 +10,7 @@
 #include <stdint.h>
 
 int32_t global = 0; // Watchpoint variable declaration.
+int32_t cookie = 0;
 
 static void modify(int32_t &var) {
     ++var;
@@ -19,10 +20,9 @@
     int local = 0;
     printf("&global=%p\n", &global);
     printf("about to write to 'global'...\n"); // Set break point at this line.
-                                               // When stopped, watch 'global',
-                                               // for the condition "global == 5".
     for (int i = 0; i < 10; ++i)
         modify(global);
 
     printf("global=%d\n", global);
+    printf("cookie=%d\n", cookie);
 }



