[FRONTEND] Minor accumulated style and warning fixes (#388)

- Fix some whitespace.
- Make an undeclared dependency on `pytest` explicit.
- Fix deprecated `description-file` use.
- `#ifdef` out a deprecated `PyEval_InitThreads` call.
- Use a slightly different numpy invocation in `test_random.py` to quiet down overflow warnings in tests.
- Fix a deprecated cast in `test_core.py`.
- Suppress a warning about `visit_Constant` in Python 3.9+; we can't migrate yet because it'd break Python 3.6 and 3.7.
- Use chained exceptions for `CompilationError` rather than rolling our own; it makes the error messages nicer.
- Add a `__str__` for `tl.dtype` to make debugging kernels easier; it lets you `print` a dtype to see what type was inferred.
- Fix a few bad escapes.

python/requirements-test.txt

@@ -1 +1,2 @@
+pytest
 scipy >= 1.7.1

python/setup.cfg

@@ -1,2 +1,2 @@
 [metadata]
-description-file = README.md
+description_file = README.md

python/src/pybind11/detail/internals.h

@@ -197,7 +197,9 @@ PYBIND11_NOINLINE inline internals &get_internals() {
         auto *&internals_ptr = *internals_pp;
         internals_ptr = new internals();
 #if defined(WITH_THREAD)
+        #if PY_VERSION_HEX < 0x03090000
         PyEval_InitThreads();
+        #endif
         PyThreadState *tstate = PyThreadState_Get();
         #if PY_VERSION_HEX >= 0x03070000
             internals_ptr->tstate = PyThread_tss_alloc();

python/test/unit/language/test_core.py

@@ -339,7 +339,8 @@ def test_atomic_rmw(op, dtype_x, mode, device='cuda'):
     ('float32', 'int32', True)
 ])
 def test_cast(dtype_x, dtype_z, bitcast, device='cuda'):
-    x = torch.tensor([43.5], dtype=cvt[dtype_x], device=device)
+    x0 = 43 if dtype_x.startswith('int') else 43.5
+    x = torch.tensor([x0], dtype=cvt[dtype_x], device=device)
 
     # triton kernel
     @triton.jit

python/test/unit/language/test_random.py

@@ -74,9 +74,8 @@ class CustomPhilox4x:
         return np.array([ret0, ret1, ret2, ret3], dtype=self._dtype)
 
     def _raise_key(self, key):
-        ret0 = key[0] + self._config.PHILOX_KEY_A
+        pk = [self._config.PHILOX_KEY_A, self._config.PHILOX_KEY_B]
-        ret1 = key[1] + self._config.PHILOX_KEY_B
+        return key + np.array(pk, dtype=self._dtype)
-        return np.array([ret0, ret1], dtype=self._dtype)
 
     def random_raw(self):
         counter = self._counter

python/triton/code_gen.py

@@ -10,6 +10,7 @@ import os
 import pickle
 import subprocess
 import os
+import warnings
 from .tools.disasm import extract
 import torch
 import triton
@@ -475,6 +476,10 @@ class CodeGenerator(ast.NodeVisitor):
     def visit(self, node):
         if node is not None:
             self.last_node = node
+        with warnings.catch_warnings():
+            # The ast library added visit_Constant and deprecated some other
+            # methods but we can't move to that without breaking Python 3.6 and 3.7.
+            warnings.simplefilter("ignore", DeprecationWarning)
             return super().visit(node)
 
     def generic_visit(self, node):
@@ -512,12 +517,11 @@ class LoadedBinary:
 
 
 class CompilationError(Exception):
-    def __init__(self, src, node, err):
+    def __init__(self, src, node):
         self.message = '\n'.join(src.split('\n')[:node.lineno])
         self.message += '\n' + ' ' * node.col_offset + '^'
-        self.message += '\n Error: ' + str(err)
         super().__init__(self.message)
-        self.args = (src, node, err)
+        self.args = (src, node)
 
 
 class OutOfResources(Exception):
@@ -618,7 +622,7 @@ class Kernel:
             node = generator.last_node
             if node is None or isinstance(e, (NotImplementedError, CompilationError)):
                 raise e
-            raise CompilationError(self.fn.src, node, e)
+            raise CompilationError(self.fn.src, node) from e
         # Compile to machine code
         if torch.version.hip is None:
             backend = _triton.runtime.backend.CUDA

python/triton/language/__init__.py

@@ -1,4 +1,3 @@
-from . import core
+from . import core, random
-from . import random
 from .core import *
-from .random import *
+from .random import rand, randint, randint4x, randn

python/triton/language/core.py

@@ -72,6 +72,9 @@ class dtype:
         ctx = builder.context
         return self.init(ctx)
 
+    def __str__(self):
+        return f"dtype({self.init.__name__})"
+
 
 class pointer_dtype:
     def __init__(self, element_ty):

python/triton/language/random.py

@@ -134,7 +134,7 @@ def pair_uniform_to_normal(u1, u2):
 def randn(seed, offset, n_rounds: tl.constexpr = N_ROUNDS_DEFAULT):
     """
     Given a :code:`seed` scalar and an :code:`offset` block, 
-    returns a block of random :code:`float32` in :math:`\mathcal{N}(0, 1)`
+    returns a block of random :code:`float32` in :math:`\\mathcal{N}(0, 1)`
 
     :param seed: The seed for generating random numbers.
     :param offsets: The offsets to generate random numbers for.
@@ -149,7 +149,7 @@ def randn(seed, offset, n_rounds: tl.constexpr = N_ROUNDS_DEFAULT):
 def randn4x(seed, offset, n_rounds: tl.constexpr = N_ROUNDS_DEFAULT):
     """
     Given a :code:`seed` scalar and an :code:`offset` block,
-    returns a 4 blocks of random :code:`float32` in :math:`\mathcal{N}(0, 1)`
+    returns a 4 blocks of random :code:`float32` in :math:`\\mathcal{N}(0, 1)`
 
     :param seed: The seed for generating random numbers.
     :param offsets: The offsets to generate random numbers for.