When using the `script` Python repl, SB objects are printed in a way that gives
the user no information. The simplest example is:
```
(lldb) script lldb.debugger
<lldb.SBDebugger; proxy of <Swig Object of type 'lldb::SBDebugger *' at 0x1097a5de0> >
```
This output comes from the Python repl printing the `repr()` of an object.
None of the SB classes implement `__repr__`, and all print like the above.
However, many (most?, all?) SB classes implement `__str__`. Because they
implement `__str__`, a more detailed output can be had by `print`ing the
object, for example:
```
(lldb) script print(lldb.debugger)
Debugger (instance: "debugger_1", id: 1)
```
For convenience, this change switches all SB classes that implement to
`__str__` to instead implement `__repr__`. **The result is that `str()` and
`repr()` will produce the same output**. This is because `str` calls `__repr__`
for classes that have no `__str__` method.
The benefit being that when writing a `script` invocation, you don't need to
remember to wrap in `print()`. If that isn't enough motivation, consider the
case where your Python expression results in a list of SB objects, in that case
you'd have to `map` or use a list comprehension like `[str(x) for x in <expr>]`
in order to see the details of the objects in the list.
For reference, the docs for `repr` say:
> repr(object)
> Return a string containing a printable representation of an object. For
> many types, this function makes an attempt to return a string that would
> yield an object with the same value when passed to eval(); otherwise, the
> representation is a string enclosed in angle brackets that contains the
> name of the type of the object together with additional information often
> including the name and address of the object. A class can control what this
> function returns for its instances by defining a __repr__() method.
and the docs for `__repr__` say:
> object.__repr__(self)
> Called by the repr() built-in function to compute the “official” string
> representation of an object. If at all possible, this should look like a
> valid Python expression that could be used to recreate an object with the
> same value (given an appropriate environment). If this is not possible, a
> string of the form <...some useful description...> should be returned. The
> return value must be a string object. If a class defines __repr__() but not
> __str__(), then __repr__() is also used when an “informal” string
> representation of instances of that class is required.
>
> This is typically used for debugging, so it is important that the
> representation is information-rich and unambiguous.
Even if it were convenient to construct Python expressions for SB classes so
that they could be `eval`'d, however for typical lldb usage, I can't think of a
motivating reason to do so. As it stands, the only action the docs say to do,
that this change doesn't do, is wrap the `repr` string in `<>` angle brackets.
An alternative implementation is to change lldb's python repl to apply `str()`
to the top level result. While this would work well in the case of a single SB
object, it doesn't work for a list of SB objects, since `str([x])` uses `repr`
to convert each list element to a string.
Differential Revision: https://reviews.llvm.org/D127458
%define STRING_EXTENSION_LEVEL(Class, Level)
%extend {
- std::string lldb:: ## Class ## ::__str__(){
+ std::string lldb:: ## Class ## ::__repr__(){
lldb::SBStream stream;
$self->GetDescription (stream, Level);
const char *desc = stream.GetData();
%define STRING_EXTENSION(Class)
%extend {
- std::string lldb:: ## Class ## ::__str__(){
+ std::string lldb:: ## Class ## ::__repr__(){
lldb::SBStream stream;
$self->GetDescription (stream);
const char *desc = stream.GetData();
--- /dev/null
+"""
+This is a sanity check that verifies that `repr(sbobject)` and `str(sbobject)`
+produce the same string.
+"""
+
+
+import lldb
+from lldbsuite.test.lldbtest import *
+
+
+class TestCase(TestBase):
+
+ mydir = TestBase.compute_mydir(__file__)
+
+ NO_DEBUG_INFO_TESTCASE = True
+
+ def test(self):
+ self.assertEqual(repr(self.dbg), str(self.dbg))
breakpoint set -f hello.cpp -p Hello
run
script print(lldb.debugger)
+script lldb.debugger
script print(lldb.target)
+script lldb.target
script print(lldb.process)
+script lldb.process
script print(lldb.thread.GetStopDescription(100))
script lldb.frame.GetLineEntry().GetLine()
script lldb.frame.GetLineEntry().GetFileSpec().GetFilename()
CHECK: stop reason = breakpoint 1.1
CHECK: script print(lldb.debugger)
CHECK-NEXT: Debugger (instance: {{.*}}, id: {{[0-9]+}})
+CHECK: script lldb.debugger
+CHECK-NEXT: Debugger (instance: {{.*}}, id: {{[0-9]+}})
CHECK: script print(lldb.target)
CHECK-NEXT: target.out
+CHECK: script lldb.target
+CHECK-NEXT: target.out
CHECK: script print(lldb.process)
CHECK-NEXT: SBProcess: pid = {{[0-9]+}}, state = stopped, threads = {{[0-9]+}}, executable = target.out
+CHECK: script lldb.process
+CHECK-NEXT: SBProcess: pid = {{[0-9]+}}, state = stopped, threads = {{[0-9]+}}, executable = target.out
CHECK: script print(lldb.thread.GetStopDescription(100))
CHECK-NEXT: breakpoint 1.1
CHECK: script lldb.frame.GetLineEntry().GetLine()
projects / platform / upstream / llvm.git / commitdiff