155 lines
5.3 KiB
Diff
155 lines
5.3 KiB
Diff
http://sourceware.org/ml/archer/2011-q1/msg00024.html
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Subject: [patch] Fix RH BZ 672235
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Bug:
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http://bugzilla.redhat.com/show_bug.cgi?id=672235
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The latter half of this bug was caused by removing the value function
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from gdb.Symbol. This happened quite some time ago, so I am a little
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surprised it took this long to surface.
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The old Symbol.value function never returned anything except a gdb.Block
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if the symbol happened to represent a function a block. Anything else
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raised an error. Way back when, I removed this function as it was an
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obvious stub, and it was superseded by frame.read_var() which is a more
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accurate method of determining the value of a symbol.
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Wind forward to today, and it turns out one of the unported
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archer-tromey-python scripts we ship in Fedora relies on this (symbol ->
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block) API. I thought about ways of trying to fix this. I thought about
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just changing FrameWrapper to just take a block instead of a symbol
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representing a function. But FrameWrapper has an API that we shipped.
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I tried to find the block through the existing API, but that did not
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work too well. The gdb.Block method block_for_pc can return a block
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from a pc but this just turned out to be expensive and convoluted. I
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eventually just elected to add a block() function to gdb.Symbol which,
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if the symbol represented a method or a function, would return the block.
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Yet I am still not entirely satisfied. It seems weird to ask the user
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to retrieve symbol value from frame.read_var for most symbols, but in
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the case of a function or method, use block(). I tried to use read_var
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for this, but it returns a gdb.Value, and I could not figure out a way to
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transform a gdb.Value to a gdb.Block.
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Before I submit this for upstream review I'd like to see if anyone has
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any comments.
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Cheers
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Phil
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--
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diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
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index 161ac1f..55eca2a 100644
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--- a/gdb/doc/gdb.texinfo
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+++ b/gdb/doc/gdb.texinfo
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@@ -22718,6 +22718,13 @@ domain constant defined in the @code{gdb} module and described later
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in this chapter.
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@end defun
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+A @code{gdb.Symbol} object has the following methods:
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+
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+@defmethod Symbol block
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+Returns a @code{gdb.Block} object if the symbol is a function or a
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+method. @xref{Blocks In Python}.
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+@end defmethod
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+
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A @code{gdb.Symbol} object has the following attributes:
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@table @code
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diff --git a/gdb/python/lib/gdb/FrameWrapper.py b/gdb/python/lib/gdb/FrameWrapper.py
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index b790a54..5d98b0f 100644
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--- a/gdb/python/lib/gdb/FrameWrapper.py
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+++ b/gdb/python/lib/gdb/FrameWrapper.py
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@@ -46,7 +46,7 @@ class FrameWrapper:
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return
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first = True
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- block = func.value
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+ block = func.block ()
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for sym in block:
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if sym.is_argument:
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@@ -60,7 +60,7 @@ class FrameWrapper:
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return
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first = True
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- block = func.value
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+ block = func.block ()
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for sym in block:
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if not sym.is_argument:
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diff --git a/gdb/python/py-symbol.c b/gdb/python/py-symbol.c
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index e072dc8..1dfe394 100644
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--- a/gdb/python/py-symbol.c
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+++ b/gdb/python/py-symbol.c
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@@ -167,6 +167,27 @@ sympy_is_variable (PyObject *self, void *closure)
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|| class == LOC_OPTIMIZED_OUT));
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}
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+static PyObject *
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+sympy_get_block (PyObject *self, PyObject *args)
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+{
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+ struct symbol *symbol = NULL;
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+
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+ SYMPY_REQUIRE_VALID (self, symbol);
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+
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+ if (SYMBOL_CLASS (symbol) == LOC_BLOCK)
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+ {
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+ struct symtab *symt = SYMBOL_SYMTAB (symbol);
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+
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+ return block_to_block_object (SYMBOL_BLOCK_VALUE (symbol),
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+ symt->objfile);
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+ }
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+ else
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+ PyErr_SetString (PyExc_RuntimeError,
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+ _("Symbol is not a block class."));
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+
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+ return NULL;
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+}
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+
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/* Given a symbol, and a symbol_object that has previously been
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allocated and initialized, populate the symbol_object with the
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struct symbol data. Also, register the symbol_object life-cycle
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@@ -362,6 +383,13 @@ gdbpy_initialize_symbols (void)
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+static PyMethodDef symbol_object_methods[] = {
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+ { "block", sympy_get_block, METH_NOARGS,
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+ "block () -> gdb.Block.\n\
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+Return the block of this symbol, if the symbol represents a function." },
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+ {NULL} /* Sentinel */
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+};
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+
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static PyGetSetDef symbol_object_getset[] = {
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{ "symtab", sympy_get_symtab, NULL,
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"Symbol table in which the symbol appears.", NULL },
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@@ -415,7 +443,7 @@ PyTypeObject symbol_object_type = {
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0, /*tp_weaklistoffset */
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0, /*tp_iter */
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0, /*tp_iternext */
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- 0, /*tp_methods */
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+ symbol_object_methods, /*tp_methods */
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0, /*tp_members */
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symbol_object_getset /*tp_getset */
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};
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diff --git a/gdb/testsuite/gdb.python/py-symbol.exp b/gdb/testsuite/gdb.python/py-symbol.exp
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index 8e3aec1..6d43566 100644
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--- a/gdb/testsuite/gdb.python/py-symbol.exp
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+++ b/gdb/testsuite/gdb.python/py-symbol.exp
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@@ -69,6 +69,10 @@ gdb_test "python print func.print_name" "func" "Test func.print_name"
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gdb_test "python print func.linkage_name" "func" "Test func.linkage_name"
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gdb_test "python print func.addr_class == gdb.SYMBOL_LOC_BLOCK" "True" "Test func.addr_class"
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+# Test block() method
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+gdb_py_test_silent_cmd "python func = frame.block().function" "Get block" 0
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+gdb_test "python print func.block().function.name" "func" "Test block method"
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+
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gdb_breakpoint [gdb_get_line_number "Break at end."]
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gdb_continue_to_breakpoint "Break at end."
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gdb_py_test_silent_cmd "python frame = gdb.selected_frame()" "Get Frame" 0
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