[FRONTEND] better stringification (#394)

- Don't override `self.args` in `CompilationError`, and show the line number and column in error messages. This causes it to generate an easier-to-read backtrace.
- Better `__str__` on `TensorWrapper`, `dtype`, and `block`.

python/triton/code_gen.py

@@ -521,10 +521,10 @@ class LoadedBinary:
 
 class CompilationError(Exception):
     def __init__(self, src, node):
-        self.message = '\n'.join(src.split('\n')[:node.lineno])
+        self.message = f'at {node.lineno}:{node.col_offset}:\n'
+        self.message += '\n'.join(src.split('\n')[:node.lineno])
         self.message += '\n' + ' ' * node.col_offset + '^'
         super().__init__(self.message)
-        self.args = (src, node)
 
 
 class OutOfResources(Exception):
@@ -1085,6 +1085,9 @@ class TensorWrapper:
     def data_ptr(self):
         return self.base.data_ptr()
 
+    def __str__(self) -> str:
+        return f'TensorWrapper[{self.dtype}]({self.base})'
+
 
 def reinterpret(tensor, dtype):
     return TensorWrapper(tensor, dtype)

python/triton/language/core.py

@@ -68,12 +68,20 @@ class dtype:
     def __init__(self, init):
         self.init = init
 
+    @property
+    def name(self) -> str:
+        # The init functions are named something like 'get_int8'. Strip the prefix.
+        nom = self.init.__name__
+        prefix = 'get_'
+        assert nom.startswith(prefix)
+        return nom[len(prefix):]
+
     def handle(self, builder):
         ctx = builder.context
         return self.init(ctx)
 
     def __str__(self):
-        return f"dtype({self.init.__name__})"
+        return self.name
 
 
 class pointer_dtype:
@@ -131,6 +139,10 @@ class block:
         # Data-type wrapper
         self.dtype = block._init_dtype(self.handle.type.scalar)
 
+    def __str__(self) -> str:
+        # ex. "float32[3,4]"
+        return str(self.dtype) + '[' + ','.join(str(s) for s in self.shape) + ']'
+
     @builtin
     def __add__(self, other, _builder=None):
         return frontend.add(self, other, _builder)