Add Python 3.14 support

.github/workflows/builds.yaml

@@ -43,7 +43,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.11", "3.12", "3.13", "3.14"]
     needs: [ruff]
     steps:
     - uses: actions/checkout@v4

README.md

@@ -4,7 +4,7 @@ Atheris is a coverage-guided Python fuzzing engine. It supports fuzzing of Pytho
 
 ## Installation Instructions
 
-Atheris supports Linux (32- and 64-bit) and Mac OS X, Python versions 3.11-3.13.
+Atheris supports Linux (32- and 64-bit) and Mac OS X, Python versions 3.11-3.14.
 Versions 3.10 and below are not supported in the current source version, but
 remain accessible in PyPI.
 

deployment/Dockerfile

@@ -39,13 +39,15 @@ RUN set -e -x -v; \
 RUN set -e -x -v; \
     /opt/python/cp311-cp311/bin/python3 -m pip install setuptools && \
     /opt/python/cp312-cp312/bin/python3 -m pip install setuptools && \
-    /opt/python/cp313-cp313/bin/python3 -m pip install setuptools;
+    /opt/python/cp313-cp313/bin/python3 -m pip install setuptools && \
+    /opt/python/cp314-cp314/bin/python3 -m pip install setuptools;
 
 WORKDIR /atheris
 
 CMD export LIBFUZZER_LIB="/root/llvm-project/build/lib/clang/$(ls /root/llvm-project/build/lib/clang/)/lib/x86_64-unknown-linux-gnu/libclang_rt.fuzzer_no_main.a"; \
 	/opt/python/cp311-cp311/bin/python3 setup.py bdist_wheel -d /tmp/dist && \
 	/opt/python/cp312-cp312/bin/python3 setup.py bdist_wheel -d /tmp/dist && \
 	/opt/python/cp313-cp313/bin/python3 setup.py bdist_wheel -d /tmp/dist && \
+	/opt/python/cp314-cp314/bin/python3 setup.py bdist_wheel -d /tmp/dist && \
 	( cd /tmp/dist && find /tmp/dist/* | xargs -I{} auditwheel repair --plat manylinux2014_x86_64 {} ) && \
 	mkdir -p /atheris/dist && cp /tmp/dist/wheelhouse/* /atheris/dist/

src/instrument_bytecode.py

@@ -33,6 +33,7 @@
 from .version_dependent import CALLABLE_STACK_ENTRIES
 from .version_dependent import CMP_OP_SHIFT_AMOUNT
 from .version_dependent import CONDITIONAL_JUMPS
+from .version_dependent import CONST_LOADS
 from .version_dependent import ExceptionTable
 from .version_dependent import ExceptionTableEntry
 from .version_dependent import generate_exceptiontable
@@ -810,7 +811,7 @@ def trace_data_flow(self) -> None:
     seen_consts = []
 
     for c, instr in enumerate(self.instructions):
-      if instr.mnemonic == "LOAD_CONST":
+      if instr.mnemonic in CONST_LOADS:
         seen_consts.append(stack_size)
       elif instr.mnemonic == "COMPARE_OP" and (
           instr.arg >> CMP_OP_SHIFT_AMOUNT

src/instrument_bytecode_test.py

@@ -617,16 +617,17 @@ def near_extended_arg(x, y):
         pass
         pass
         pass
-        pass
         return x
       return y
 
     original_code = near_extended_arg.__code__
 
     # Ensure that the original code does not contain any EXTENDED_ARG
-    # instructions.
-    for inst in original_code.co_code:
-      self.assertNotEqual(dis.opname[inst], "EXTENDED_ARG")
+    # instructions. `dis.get_instructions` decodes properly so argument
+    # bytes that happen to equal the EXTENDED_ARG opcode value are not
+    # mistaken for opcodes.
+    for instr in dis.get_instructions(original_code):
+      self.assertNotEqual(instr.opname, "EXTENDED_ARG")
 
     patched_code = instrument_bytecode.patch_code(
         original_code, trace_dataflow=True
@@ -635,8 +636,8 @@ def near_extended_arg(x, y):
     mockutils.UpdateCounterArrays()
 
     # Ensure that the patched code contains EXTENDED_ARG instructions.
-    for inst in patched_code.co_code:
-      if dis.opname[inst] == "EXTENDED_ARG":
+    for instr in dis.get_instructions(patched_code):
+      if instr.opname == "EXTENDED_ARG":
         break
     else:
       self.fail("No EXTENDED_ARG instructions found in patched code.")

src/version_dependent.py

@@ -24,6 +24,7 @@
     - 3.11
     - 3.12
     - 3.13
+    - 3.14
 """
 
 import sys
@@ -34,10 +35,10 @@
 
 PYTHON_VERSION = sys.version_info[:2]
 
-if PYTHON_VERSION < (3, 6) or PYTHON_VERSION > (3, 13):
+if PYTHON_VERSION < (3, 6) or PYTHON_VERSION > (3, 14):
   raise RuntimeError(
       "You are fuzzing on an unsupported python version: "
-      + f"{PYTHON_VERSION[0]}.{PYTHON_VERSION[1]}. Only 3.6 - 3.12 are "
+      + f"{PYTHON_VERSION[0]}.{PYTHON_VERSION[1]}. Only 3.6 - 3.14 are "
       + "supported by atheris 2.0. Use atheris 1.0 for older python versions."
   )
 
@@ -118,6 +119,27 @@
       "POP_JUMP_IF_NOT_NONE",
   ])
 
+if PYTHON_VERSION >= (3, 14):
+  # 3.14 added non-popping conditional jumps `JUMP_IF_TRUE` / `JUMP_IF_FALSE`
+  # as relative-forward branches; the existing pop-then-jump pair stays.
+  CONDITIONAL_JUMPS.extend([
+      "JUMP_IF_FALSE",
+      "JUMP_IF_TRUE",
+  ])
+  HAVE_REL_REFERENCE.extend([
+      "JUMP_IF_FALSE",
+      "JUMP_IF_TRUE",
+  ])
+
+# Instructions that push a constant onto the stack. The constant-compare
+# instrumentation tracks which stack slots hold constants so it can pass the
+# constant value to `_trace_cmp` as `obj1`. 3.14 introduced `LOAD_SMALL_INT`
+# as a specialized constant-loader for small integers; before 3.14 all
+# constants flowed through `LOAD_CONST` so this list was implicit.
+CONST_LOADS = ["LOAD_CONST"]
+if PYTHON_VERSION >= (3, 14):
+  CONST_LOADS.append("LOAD_SMALL_INT")
+
 HAVE_ABS_REFERENCE = [
     # common
     "JUMP_ABSOLUTE",