Add GDB pretty printer module

Author: mborland

extra/decimal_printer_gdb.py

@@ -0,0 +1,172 @@
+# Copyright 2025 Matt Borland
+# Distributed under the Boost Software License, Version 1.0.
+# https://www.boost.org/LICENSE_1_0.txt
+
+from detail.decode_ieee_type import decode_decimal32
+from detail.decode_ieee_type import decode_decimal64
+from detail.decode_ieee_type import decode_decimal128
+from detail.decode_fast_type import decode_decimal_fast32
+from detail.decode_fast_type import decode_decimal_fast64
+from detail.decode_fast_type import decode_decimal_fast128
+
+import gdb
+import gdb.printing
+
+class Decimal32Printer:
+    """Pretty printer for decimal32_t type"""
+
+    def __init__(self, val):
+        self.val = val
+
+    def to_string(self):
+        try:
+            bits = int(self.val['bits_'])
+            return decode_decimal32(bits)
+        except Exception as e:
+            return f"<invalid decimal32_t: {e}>"
+
+    def children(self):
+        yield ('bits_', self.val['bits_'])
+
+
+class Decimal64Printer:
+    """Pretty printer for decimal64_t type"""
+
+    def __init__(self, val):
+        self.val = val
+
+    def to_string(self):
+        try:
+            bits = int(self.val['bits_'])
+            return decode_decimal64(bits)
+        except Exception as e:
+            return f"<invalid decimal64_t: {e}>"
+
+    def children(self):
+        yield ('bits_', self.val['bits_'])
+
+
+class Decimal128Printer:
+    """Pretty printer for decimal128_t type"""
+
+    def __init__(self, val):
+        self.val = val
+
+    def to_string(self):
+        try:
+            bits = self.val['bits_']
+            bits_high = int(bits['high'])
+            bits_low = int(bits['low'])
+            combined_bits = (bits_high << 64) | bits_low
+            return decode_decimal128(combined_bits)
+        except Exception as e:
+            return f"<invalid decimal128_t: {e}>"
+
+    def children(self):
+        yield ('bits_', self.val['bits_'])
+
+
+class DecimalFast32Printer:
+    """Pretty printer for decimal_fast32_t type"""
+
+    def __init__(self, val):
+        self.val = val
+
+    def to_string(self):
+        try:
+            significand = int(self.val['significand_'])
+            exp = int(self.val['exponent_'])
+            sign = int(self.val['sign_'])
+            return decode_decimal_fast32(significand, exp, sign)
+        except Exception as e:
+            return f"<invalid decimal_fast32_t: {e}>"
+
+    def children(self):
+        yield ('significand_', self.val['significand_'])
+        yield ('exponent_', self.val['exponent_'])
+        yield ('sign_', self.val['sign_'])
+
+
+class DecimalFast64Printer:
+    """Pretty printer for decimal_fast64_t type"""
+
+    def __init__(self, val):
+        self.val = val
+
+    def to_string(self):
+        try:
+            significand = int(self.val['significand_'])
+            exp = int(self.val['exponent_'])
+            sign = int(self.val['sign_'])
+            return decode_decimal_fast64(significand, exp, sign)
+        except Exception as e:
+            return f"<invalid decimal_fast64_t: {e}>"
+
+    def children(self):
+        yield ('significand_', self.val['significand_'])
+        yield ('exponent_', self.val['exponent_'])
+        yield ('sign_', self.val['sign_'])
+
+
+class DecimalFast128Printer:
+    """Pretty printer for decimal_fast128_t type"""
+
+    def __init__(self, val):
+        self.val = val
+
+    def to_string(self):
+        try:
+            significand = self.val['significand_']
+            bits_high = int(significand['high'])
+            bits_low = int(significand['low'])
+            combined_bits = (bits_high << 64) | bits_low
+
+            exp = int(self.val['exponent_'])
+            sign = int(self.val['sign_'])
+
+            return decode_decimal_fast128(combined_bits, exp, sign)
+        except Exception as e:
+            return f"<invalid decimal_fast128_t: {e}>"
+
+    def children(self):
+        yield ('significand_', self.val['significand_'])
+        yield ('exponent_', self.val['exponent_'])
+        yield ('sign_', self.val['sign_'])
+
+
+def build_pretty_printer():
+    """Build and return the pretty printer collection"""
+    pp = gdb.printing.RegexpCollectionPrettyPrinter("boost_decimal")
+
+    # IEEE types
+    pp.add_printer('decimal32_t',
+                   r'^(const )?(boost::decimal::)?decimal32_t( &| \*)?$',
+                   Decimal32Printer)
+    pp.add_printer('decimal64_t',
+                   r'^(const )?(boost::decimal::)?decimal64_t( &| \*)?$',
+                   Decimal64Printer)
+    pp.add_printer('decimal128_t',
+                   r'^(const )?(boost::decimal::)?decimal128_t( &| \*)?$',
+                   Decimal128Printer)
+
+    # Fast types
+    pp.add_printer('decimal_fast32_t',
+                   r'^(const )?(boost::decimal::)?decimal_fast32_t( &| \*)?$',
+                   DecimalFast32Printer)
+    pp.add_printer('decimal_fast64_t',
+                   r'^(const )?(boost::decimal::)?decimal_fast64_t( &| \*)?$',
+                   DecimalFast64Printer)
+    pp.add_printer('decimal_fast128_t',
+                   r'^(const )?(boost::decimal::)?decimal_fast128_t( &| \*)?$',
+                   DecimalFast128Printer)
+
+    return pp
+
+
+def register_printers(objfile=None):
+    gdb.printing.register_pretty_printer(objfile, build_pretty_printer())
+
+
+# Auto-register when the module is loaded
+register_printers()
+print("Boost.Decimal pretty printers loaded successfully")