Add trap codes to the Cretonne IL.

The trap and trapz/trapnz instructions now take a trap code immediate
operand which indicates the reason for trapping.

lib/cretonne/meta/base/formats.py

@@ -9,7 +9,7 @@ from __future__ import absolute_import
 from cdsl.formats import InstructionFormat
 from cdsl.operands import VALUE, VARIABLE_ARGS
 from .immediates import imm64, uimm8, uimm32, ieee32, ieee64, offset32
-from .immediates import boolean, intcc, floatcc, memflags, regunit
+from .immediates import boolean, intcc, floatcc, memflags, regunit, trapcode
 from . import entities
 from .entities import ebb, sig_ref, func_ref, stack_slot, heap
 
@@ -61,5 +61,8 @@ HeapAddr = InstructionFormat(heap, VALUE, uimm32)
 
 RegMove = InstructionFormat(VALUE, ('src', regunit), ('dst', regunit))
 
+Trap = InstructionFormat(trapcode)
+CondTrap = InstructionFormat(VALUE, trapcode)
+
 # Finally extract the names of global variables in this module.
 InstructionFormat.extract_names(globals())

lib/cretonne/meta/base/immediates.py

@@ -105,3 +105,19 @@ regunit = ImmediateKind(
         'regunit',
         'A register unit in the target ISA',
         rust_type='isa::RegUnit')
+
+#: A trap code indicating the reason for trapping.
+#:
+#: The Rust enum type also has a `User(u16)` variant for user-provided trap
+#: codes.
+trapcode = ImmediateKind(
+        'trapcode',
+        'A trap reason code.',
+        default_member='code',
+        rust_type='ir::TrapCode',
+        values={
+            "stk_ovf": 'StackOverflow',
+            "heap_oob": 'HeapOutOfBounds',
+            "int_ovf": 'IntegerOverflow',
+            "int_divz": 'IntegerDivisionByZero',
+        })

lib/cretonne/meta/base/instructions.py

@@ -11,6 +11,7 @@ from cdsl.instructions import Instruction, InstructionGroup
 from base.types import f32, f64, b1
 from base.immediates import imm64, uimm8, uimm32, ieee32, ieee64, offset32
 from base.immediates import boolean, intcc, floatcc, memflags, regunit
+from base.immediates import trapcode
 from base import entities
 from cdsl.ti import WiderOrEq
 import base.formats  # noqa
@@ -126,11 +127,12 @@ br_table = Instruction(
         """,
         ins=(x, JT), is_branch=True)
 
+code = Operand('code', trapcode)
 trap = Instruction(
         'trap', r"""
         Terminate execution unconditionally.
         """,
-        is_terminator=True, can_trap=True)
+        ins=code, is_terminator=True, can_trap=True)
 
 trapz = Instruction(
         'trapz', r"""
@@ -138,7 +140,7 @@ trapz = Instruction(
 
         if ``c`` is non-zero, execution continues at the following instruction.
         """,
-        ins=c, can_trap=True)
+        ins=(c, code), can_trap=True)
 
 trapnz = Instruction(
         'trapnz', r"""
@@ -146,7 +148,7 @@ trapnz = Instruction(
 
         if ``c`` is zero, execution continues at the following instruction.
         """,
-        ins=c, can_trap=True)
+        ins=(c, code), can_trap=True)
 
 rvals = Operand('rvals', VARIABLE_ARGS, doc='return values')