implement sys._getframe + frame objects, and add co_name/co_filename properties to code object

also rework a bit of the logging module to use only sys._getframe, not f_back.

from_cpython/Lib/logging/__init__.py

@@ -71,15 +71,9 @@ else:
     _srcfile = __file__
 _srcfile = os.path.normcase(_srcfile)
 
-# next bit filched from 1.5.2's inspect.py
-def currentframe():
-    """Return the frame object for the caller's stack frame."""
-    try:
-        raise Exception
-    except:
-        return sys.exc_info()[2].tb_frame.f_back
-
-if hasattr(sys, '_getframe'): currentframe = lambda: sys._getframe(3)
+# pyston changes: we don't support tb_frame or f_back, so always use sys._getframe
+currentframe = lambda: sys._getframe(4)
+start_getframe = 4
 # done filching
 
 # _srcfile is only used in conjunction with sys._getframe().
@@ -1229,20 +1223,22 @@ class Logger(Filterer):
         file name, line number and function name.
         """
 
-        # Pyston change:
-        return "(unknown file)", 0, "(unknown function)"
-
         f = currentframe()
+        # pyston change: we can't use f_back to walk back up the stack, so increment a counter of
+        # frames to skip and repeatedly call sys._getframe
+        fn = start_getframe
         #On some versions of IronPython, currentframe() returns None if
         #IronPython isn't run with -X:Frames.
-        if f is not None:
-            f = f.f_back
+        #if f is not None:
+        #    f = f.f_back
         rv = "(unknown file)", 0, "(unknown function)"
         while hasattr(f, "f_code"):
             co = f.f_code
             filename = os.path.normcase(co.co_filename)
             if filename == _srcfile:
-                f = f.f_back
+                fn += 1
+                f = sys._getframe(fn);
+                #f = f.f_back
                 continue
             rv = (co.co_filename, f.f_lineno, co.co_name)
             break

src/codegen/unwinding.cpp

@@ -644,8 +644,11 @@ FrameStackState getFrameStackState() {
     RELEASE_ASSERT(0, "Internal error: unable to find any python frames");
 }
 
-Box* fastLocalsToBoxedLocals() {
+Box* fastLocalsToBoxedLocals(int framesToSkip) {
     for (PythonFrameIterator& frame_iter : unwindPythonFrames()) {
+        if (--framesToSkip >= 0)
+            continue;
+
         BoxedDict* d;
         BoxedClosure* closure;
         FrameInfo* frame_info;
@@ -798,6 +801,25 @@ ExecutionPoint getExecutionPoint() {
     return ExecutionPoint({.cf = cf, .current_stmt = current_stmt });
 }
 
+std::unique_ptr<ExecutionPoint> getExecutionPoint(int framesToSkip) {
+    CompiledFunction* cf = NULL;
+    AST_stmt* stmt = NULL;
+
+    for (PythonFrameIterator& frame_iter : unwindPythonFrames()) {
+        // skip depth frames
+        if (--framesToSkip >= 0)
+            continue;
+
+        cf = frame_iter.getCF();
+        stmt = frame_iter.getCurrentStatement();
+        break;
+    }
+    if (!cf)
+        return std::unique_ptr<ExecutionPoint>();
+
+    return std::unique_ptr<ExecutionPoint>(new ExecutionPoint({.cf = cf, .current_stmt = stmt }));
+}
+
 llvm::JITEventListener* makeTracebacksListener() {
     return new TracebacksEventListener();
 }

src/codegen/unwinding.h

@@ -32,7 +32,7 @@ BoxedModule* getCurrentModule();
 BoxedTraceback* getTraceback();
 
 // Adds stack locals and closure locals into the locals dict, and returns it.
-Box* fastLocalsToBoxedLocals();
+Box* fastLocalsToBoxedLocals(int framesToSkip = 0);
 
 // Fetches a writeable pointer to the frame-local excinfo object,
 // calculating it if necessary (from previous frames).
@@ -43,6 +43,7 @@ struct ExecutionPoint {
     AST_stmt* current_stmt;
 };
 ExecutionPoint getExecutionPoint();
+std::unique_ptr<ExecutionPoint> getExecutionPoint(int framesToSkip);
 
 struct FrameStackState {
     // This includes all # variables (but not the ! ones).

src/runtime/builtin_modules/sys.cpp

@@ -99,6 +99,22 @@ Box* getSysStdout() {
     return sys_stdout;
 }
 
+Box* sysGetFrame(Box* val) {
+    int depth = 0;
+    if (val) {
+        if (!isSubclass(val->cls, int_cls)) {
+            raiseExcHelper(TypeError, "TypeError: an integer is required");
+        }
+        depth = static_cast<BoxedInt*>(val)->n;
+    }
+
+    Box* frame = getFrame(depth);
+    if (!frame) {
+        raiseExcHelper(ValueError, "call stack is not deep enough");
+    }
+    return frame;
+}
+
 Box* sysGetDefaultEncoding() {
     return boxStrConstant(PyUnicode_GetDefaultEncoding());
 }
@@ -267,6 +283,8 @@ void setupSys() {
     main_fn = llvm::sys::fs::getMainExecutable(NULL, NULL);
     sys_module->giveAttr("executable", boxString(main_fn.str()));
 
+    sys_module->giveAttr("_getframe",
+                         new BoxedFunction(boxRTFunction((void*)sysGetFrame, UNKNOWN, 1, 1, false, false), { NULL }));
     sys_module->giveAttr(
         "getdefaultencoding",
         new BoxedBuiltinFunctionOrMethod(boxRTFunction((void*)sysGetDefaultEncoding, STR, 0), "getdefaultencoding"));

src/runtime/code.cpp

@@ -39,6 +39,16 @@ public:
         boxGCHandler(v, b);
     }
 
+    static Box* name(Box* b, void*) {
+        RELEASE_ASSERT(b->cls == code_cls, "");
+        return boxString(static_cast<BoxedCode*>(b)->f->source->getName());
+    }
+
+    static Box* filename(Box* b, void*) {
+        RELEASE_ASSERT(b->cls == code_cls, "");
+        return boxString(static_cast<BoxedCode*>(b)->f->source->parent_module->fn);
+    }
+
     static Box* argcount(Box* b, void*) {
         RELEASE_ASSERT(b->cls == code_cls, "");
 
@@ -80,12 +90,18 @@ Box* codeForFunction(BoxedFunction* f) {
     return new BoxedCode(f->f);
 }
 
+Box* codeForCLFunction(CLFunction* f) {
+    return new BoxedCode(f);
+}
+
 void setupCode() {
     code_cls
         = BoxedHeapClass::create(type_cls, object_cls, &BoxedCode::gcHandler, 0, 0, sizeof(BoxedCode), false, "code");
 
     code_cls->giveAttr("__new__", None); // Hacky way of preventing users from instantiating this
 
+    code_cls->giveAttr("co_name", new (pyston_getset_cls) BoxedGetsetDescriptor(BoxedCode::name, NULL, NULL));
+    code_cls->giveAttr("co_filename", new (pyston_getset_cls) BoxedGetsetDescriptor(BoxedCode::filename, NULL, NULL));
     code_cls->giveAttr("co_argcount", new (pyston_getset_cls) BoxedGetsetDescriptor(BoxedCode::argcount, NULL, NULL));
     code_cls->giveAttr("co_varnames", new (pyston_getset_cls) BoxedGetsetDescriptor(BoxedCode::varnames, NULL, NULL));
     code_cls->giveAttr("co_flags", new (pyston_getset_cls) BoxedGetsetDescriptor(BoxedCode::flags, NULL, NULL));

src/runtime/frame.cpp

+// Copyright (c) 2014-2015 Dropbox, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "codegen/unwinding.h"
+#include "runtime/types.h"
+
+namespace pyston {
+
+BoxedClass* frame_cls;
+
+class BoxedFrame : public Box {
+public:
+    BoxedFrame() __attribute__((visibility("default"))) {}
+
+    Box* _locals;
+    Box* _globals;
+    Box* _code;
+    uint32_t _lineno;
+
+    // cpython frame objects have the following attributes
+
+    // read-only attributes
+    //
+    // f_back[*]       : previous stack frame (toward caller)
+    // f_code          : code object being executed in this frame
+    // f_locals        : dictionary used to look up local variables in this frame
+    // f_globals       : dictionary used to look up global variables in this frame
+    // f_builtins[*]   : dictionary to look up built-in (intrinsic) names
+    // f_restricted[*] : whether this function is executing in restricted execution mode
+    // f_lasti[*]      : precise instruction (this is an index into the bytecode string of the code object)
+
+    // writable attributes
+    //
+    // f_trace[*]         : if not None, is a function called at the start of each source code line (used by debugger)
+    // f_exc_type[*],     : represent the last exception raised in the parent frame provided another exception was
+    // f_exc_value[*],    : ever raised in the current frame (in all other cases they are None).
+    // f_exc_traceback[*] :
+    // f_lineno[**]       : the current line number of the frame -- writing to this from within a trace function jumps
+    // to
+    //                    : the given line (only for the bottom-most frame).  A debugger can implement a Jump command
+    //                    (aka
+    //                    : Set Next Statement) by writing to f_lineno
+    //
+    // * = unsupported in Pyston
+    // ** = getter supported, but setter unsupported
+
+    static void gchandler(GCVisitor* v, Box* b) {
+        boxGCHandler(v, b);
+
+        auto f = static_cast<BoxedFrame*>(b);
+
+        v->visit(f->_code);
+        v->visit(f->_locals);
+        v->visit(f->_globals);
+    }
+
+    static Box* code(Box* obj, void*) {
+        auto f = static_cast<BoxedFrame*>(obj);
+        return f->_code;
+    }
+
+    static Box* locals(Box* obj, void*) {
+        auto f = static_cast<BoxedFrame*>(obj);
+        return f->_locals;
+    }
+
+    static Box* globals(Box* obj, void*) {
+        auto f = static_cast<BoxedFrame*>(obj);
+        return f->_globals;
+    }
+
+    static Box* lineno(Box* obj, void*) {
+        auto f = static_cast<BoxedFrame*>(obj);
+        return boxInt(f->_lineno);
+    }
+
+    DEFAULT_CLASS(frame_cls);
+};
+
+Box* getFrame(int depth) {
+    std::unique_ptr<ExecutionPoint> fr = getExecutionPoint(depth);
+    if (!fr)
+        return NULL;
+
+    Box* locals = fastLocalsToBoxedLocals(depth);
+
+    BoxedFrame* rtn = new BoxedFrame();
+    rtn->_locals = locals;
+    // basically the same as builtin globals()
+    // q: TODO is it ok that we don't return a real dict here?
+    rtn->_globals = makeAttrWrapper(fr->cf->clfunc->source->parent_module);
+    rtn->_code = codeForCLFunction(fr->cf->clfunc);
+    rtn->_lineno = fr->current_stmt->lineno;
+    return rtn;
+}
+
+
+void setupFrame() {
+    frame_cls = BoxedHeapClass::create(type_cls, object_cls, &BoxedFrame::gchandler, 0, 0, sizeof(BoxedFrame), false,
+                                       "frame");
+
+    frame_cls->giveAttr("f_code", new (pyston_getset_cls) BoxedGetsetDescriptor(BoxedFrame::code, NULL, NULL));
+    frame_cls->giveAttr("f_locals", new (pyston_getset_cls) BoxedGetsetDescriptor(BoxedFrame::locals, NULL, NULL));
+    frame_cls->giveAttr("f_globals", new (pyston_getset_cls) BoxedGetsetDescriptor(BoxedFrame::globals, NULL, NULL));
+
+    frame_cls->giveAttr("f_lineno", new (pyston_getset_cls) BoxedGetsetDescriptor(BoxedFrame::lineno, NULL, NULL));
+
+    frame_cls->freeze();
+}
+}

src/runtime/types.cpp

@@ -2121,6 +2121,7 @@ void setupRuntime() {
     setupDescr();
     setupTraceback();
     setupCode();
+    setupFrame();
 
     function_cls->giveAttr("__dict__", dict_descr);
     function_cls->giveAttr("__name__", new (pyston_getset_cls) BoxedGetsetDescriptor(funcName, funcSetName, NULL));

src/runtime/types.h

@@ -67,6 +67,7 @@ void setupGenerator();
 void setupDescr();
 void teardownDescr();
 void setupCode();
+void setupFrame();
 
 void setupSys();
 void setupBuiltins();
@@ -703,5 +704,8 @@ extern "C" PyObject* PystonType_GenericAlloc(BoxedClass* cls, Py_ssize_t nitems)
 extern Box* dict_descr;
 
 Box* codeForFunction(BoxedFunction*);
+Box* codeForCLFunction(CLFunction*);
+
+Box* getFrame(int depth);
 }
 #endif

test/tests/logging_test.py

+import logging
+import warnings
+
+# output something using the root logger
+def foo():
+    logging.warning("Houston, we have a %s", "bit of a problem")
+foo()
+
+import warnings
+
+def fxn():
+    warnings.warn("deprecated", DeprecationWarning)
+
+with warnings.catch_warnings(record=True) as w:
+    # Cause all warnings to always be triggered.
+    warnings.simplefilter("always")
+    # Trigger a warning.
+    fxn()
+    # Verify some things
+    assert len(w) == 1
+    assert issubclass(w[-1].category, DeprecationWarning)
+    assert "deprecated" in str(w[-1].message)
+
+print "warnings module works"

test/tests/sys_getframe1.py

+"""
+Frame Hack Recipe #1: Ruby-style string interpolation (version 1)
+"""
+# from http://farmdev.com/src/secrets/framehack/interpolate/solutions/interpolate1.py
+import sys
+from string import Template
+
+def interpolate(templateStr):
+    frame = sys._getframe(1)
+    framedict = frame.f_locals
+
+    t = Template(templateStr)
+    return t.substitute(**framedict)
+    
+name = 'Feihong'
+place = 'Chicago'
+print interpolate("My name is ${name}. I work in ${place}.")

test/tests/sys_getframe2.py

+import sys
+
+def sysframetest():
+    return sys._getframe(0)
+
+def sysframetestwrapper():
+    return sysframetest()
+
+fr = sysframetest()
+print sysframetest.__name__
+print fr.f_code.co_name
+print fr.f_code.co_filename
+
+fr = sysframetestwrapper()
+print sysframetestwrapper.__name__
+print fr.f_code.co_name
+print fr.f_code.co_filename