Merge branch 'add-frame-info-libfibre' into 'master'

Populate filename, line number, and function name in info fibres

See merge request !1

src/libfibre/libfibre.so-gdb.py

@@ -2,6 +2,7 @@
 # echo add-auto-load-safe-path . >> $HOME/.gdbinit
 
 import gdb
+from contextlib import contextmanager
 
 class FibreSupport():
     def __init__(self):
@@ -51,7 +52,7 @@ class FibreSupport():
         frame.select()
         return currframe
 
-    def set_fibre(arg):
+    def set_fibre(arg, silent=False):
         # if current pthread: use current register context
         if (arg == gdb.parse_and_eval("Context::currStack")):
             return True
@@ -60,7 +61,8 @@ class FibreSupport():
         ptr = gdb.Value(arg).cast(ftype)
         rsp = ptr['stackPointer']
         if (rsp == 0):
-            print("cannot access stack pointer - active in different thread?")
+            if not silent:
+                print("cannot access stack pointer - active in different thread?")
             return False
         ptype = gdb.lookup_type('uintptr_t').pointer()
         rsp = rsp + 40            # cf. STACK_PUSH in src/generic/regsave.h
@@ -89,6 +91,31 @@ class FibreSupport():
         # restore stack frame
         currframe.select()
 
+    # returns frame for fibre
+    @contextmanager
+    def get_frame(arg):
+        currframe = FibreSupport.prep_frame()
+        # save register context
+        tmprsp = str(gdb.parse_and_eval("$rsp")).split(None, 1)[0]
+        tmprbp = str(gdb.parse_and_eval("$rbp")).split(None, 1)[0]
+        tmprip = str(gdb.parse_and_eval("$rip")).split(None, 1)[0]
+        result = None
+        try:
+            # execute backtrace, if possible
+            if (FibreSupport.set_fibre(arg, silent=True)):
+                result = gdb.selected_frame()
+                yield result
+            else:
+                yield None
+        finally:
+            # restore register context
+            gdb.execute("set $rsp = " + str(tmprsp))
+            gdb.execute("set $rbp = " + str(tmprbp))
+            gdb.execute("set $rip = " + str(tmprip))
+            # restore stack frame
+            currframe.select()
+        return result
+
 class InfoFibres(gdb.Command):
     """Print list of fibres"""
     def __init__(self):
@@ -99,9 +126,15 @@ class InfoFibres(gdb.Command):
         for i in range(len(FibreSupport.list)):
             print(str(i), "\tFibre", str(FibreSupport.list[i]), end='')
             if (FibreSupport.list[i] == curr):
-                print(" (*)")
-            else:
-                print()
+                print(" (*)", end='')
+            with FibreSupport.get_frame(FibreSupport.list[i]) as frame:
+                if frame is not None:
+                    sal = frame.find_sal()
+                    symtab = sal.symtab
+                    print(" in ", frame.name(), sep='', end='')
+                    print(" at ", symtab.filename, ":", sal.line, sep='')
+                else:
+                    print()
 
 class Fibre(gdb.Command):
     def __init__(self):