decoder.py: allowing to use it live, fix in_stack and avoid ctx repetition

using it live:
    pyserial-miniterm /dev/ttyUSB0 115200 | decoder.py <args>

Author: d-a-v

Diff for: tools/decoder.py

@@ -96,7 +96,7 @@ def addresses_addr2line(addr2line, elf, addresses):
 
 
 def decode_lines(format_addresses, elf, lines):
-    STACK_RE = re.compile(r"^[0-9a-f]{8}:\s+([0-9a-f]{8} ?)+ *$")
+    STACK_RE = re.compile(r"^[0-9a-f]{8}:\s+([0-9a-f]{8} ?)+ *")
 
     LAST_ALLOC_RE = re.compile(
         r"last failed alloc call: ([0-9a-fA-F]{8})\(([0-9]+)\).*"
@@ -106,17 +106,23 @@ def decode_lines(format_addresses, elf, lines):
     CUT_HERE_STRING = "CUT HERE FOR EXCEPTION DECODER"
     EXCEPTION_STRING = "Exception ("
     EPC_STRING = "epc1="
+    DECODE_IT = "DECODE IT"
 
     # either print everything as-is, or cache current string and dump after stack contents end
     last_stack = None
     stack_addresses = {}
 
     in_stack = False
+    lastctx = ''
+    lastepc = 0
 
     def print_all_addresses(addresses):
+        nonlocal lastctx
         for ctx, addrs in addresses.items():
-            print()
-            print(ctx)
+            if ctx != lastctx:
+                print()
+                print(ctx)
+                lastctx = ctx
             for formatted in format_addresses(elf, addrs):
                 print(formatted)
         return dict()
@@ -138,15 +144,20 @@ def format_address(address):
             stack_addresses.setdefault(last_stack, [])
             for addr in addrs:
                 stack_addresses[last_stack].append(addr)
+            stack_addresses = print_all_addresses(stack_addresses)
         # epc1=0xfffefefe epc2=0xfefefefe epc3=0xefefefef excvaddr=0xfefefefe depc=0xfefefefe
         elif EPC_STRING in line:
             pairs = line.split()
             for pair in pairs:
                 name, addr = pair.split("=")
+                addr = addr.rstrip(',')
                 if name in ["epc1", "excvaddr"]:
-                    output = format_address(addr)
-                    if output:
-                        print(f"{name}={output}")
+                    if lastepc != addr:
+                        if addr != '0x00000000':
+                            lastepc = addr
+                        output = format_address(addr)
+                        if output:
+                            print(f"{name}={output}")
         # Exception (123):
         # Other reasons coming before the guard shown as-is
         elif EXCEPTION_STRING in line:
@@ -164,8 +175,9 @@ def format_address(address):
             in_stack = True
         # ignore
         elif "<<<stack<<<" in line:
+            in_stack = False
             continue
-        elif CUT_HERE_STRING in line:
+        elif CUT_HERE_STRING in line or DECODE_IT in line:
             continue
         else:
             line = line.strip()