mirror of
https://sourceware.org/git/binutils-gdb.git
synced 2024-11-25 02:53:48 +08:00
e68cb8e001
While the previous commit made "p method()::static_var" (no
single-quotes) Just Work, if users (or frontends) try wrapping the
expression with quotes, they'll get:
(gdb) p 'S::method()::static_var'
'S::method()::static_var' has unknown type; cast it to its declared type
even if we _do_ have debug info for that variable. That's better than
the bogus/confusing value what GDB would print before the
stop-assuming-int patch:
(gdb) p 'S::method()::static_var'
$1 = 1
but I think it'd still be nice to make this case Just Work too.
In this case, due to the quoting, the C/C++ parser (c-exp.y)
interprets the whole expression/string as a single symbol name, and we
end up calling lookup_symbol on that name. There's no debug symbol
with that fully-qualified name, but since the compiler gives the
static variable a mangled linkage name exactly like the above, it
appears in the mininal symbols:
$ nm -A local-static | c++filt | grep static_var
local-static:0000000000601040 d S::method()::static_var
... and that's what GDB happens to find/print. This only happens in
C++, note, since for C the compiler uses different linkage names:
local-static-c:0000000000601040 d static_var.1848
So while (in C++, not C) function local static variables are given a
mangled name that demangles to the same syntax that GDB
documents/expects as the way to access function local statics, there's
no global symbol in the debug info with that name at all. The debug
info for a static local variable for a non-inline function looks like
this:
<1><2a1>: Abbrev Number: 19 (DW_TAG_subprogram)
...
<2><2f7>: Abbrev Number: 20 (DW_TAG_variable)
<2f8> DW_AT_name : (indirect string, offset: 0x4e9): static_var
<2fc> DW_AT_decl_file : 1
<2fd> DW_AT_decl_line : 64
<2fe> DW_AT_type : <0x25>
<302> DW_AT_location : 9 byte block: 3 40 10 60 0 0 0 0 0 (DW_OP_addr: 601040)
and for an inline function, it looks like this (linkage name run
through c++filt for convenience):
<2><21b>: Abbrev Number: 16 (DW_TAG_variable)
<21c> DW_AT_name : (indirect string, offset: 0x21a): static_var
<220> DW_AT_decl_file : 1
<221> DW_AT_decl_line : 48
<222> DW_AT_linkage_name: (indirect string, offset: 0x200): S::inline_method()::static_var
<226> DW_AT_type : <0x25>
<22a> DW_AT_external : 1
<22a> DW_AT_location : 9 byte block: 3 a0 10 60 0 0 0 0 0 (DW_OP_addr: 6010a0)
(The inline case makes the variable external so that the linker can
merge the different inlined copies. It seems like GCC never outputs
the linkage name for non-extern globals.)
When we read the DWARF, we record the static_var variable as a regular
variable of the containing function's block. This makes stopping in
the function and printing the variable as usual. The variable just so
happens to have a memory address as location.
So one way to make "p 'S::method()::static_var'" work would be to
record _two_ copies of the symbols for these variables. One in the
function's scope/block, with "static_var" as name, as we currently do,
and another in the static or global blocks (depending on whether the
symbol is external), with a fully-qualified name. I wrote a prototype
patch for that, and it works. For the non-inline case above, since
the debug info doesn't point to the linkage same, that patch built the
physname of the static local variable as the concat of the physname of
the containing function, plus "::", plus the variable's name. We
could make that approach work for C too, though it kind of feels
awkward to record fake symbol names like that in C.
The other approach I tried is to change the C++ symbol lookup routines
instead. This is the approach this commit takes. We can already
lookup up symbol in namespaces and classes, so this feels like a good
fit, and was easy enough. The advantage is that this doesn't require
recording extra symbols.
The test in gdb.cp/m-static.exp that exposed the need for this is
removed, since the same functionality is now covered by
gdb.cp/local-static.exp.
gdb/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* cp-namespace.c (cp_search_static_and_baseclasses): Handle
function/method scopes; lookup the nested name as a function local
static variable.
gdb/testsuite/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* gdb.base/local-static.exp: Also test with
class::method::variable wholly quoted.
* gdb.cp/m-static.exp (class::method::variable): Remove test.
352 lines
13 KiB
Modula-2
352 lines
13 KiB
Modula-2
/* Standard language operator definitions for GDB, the GNU debugger.
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Copyright (C) 1986-2017 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* Used when it's necessary to pass an opcode which will be ignored,
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or to catch uninitialized values. */
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OP (OP_NULL)
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/* BINOP_... operate on two values computed by following subexpressions,
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replacing them by one result value. They take no immediate arguments. */
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OP (BINOP_ADD) /* + */
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OP (BINOP_SUB) /* - */
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OP (BINOP_MUL) /* * */
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OP (BINOP_DIV) /* / */
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OP (BINOP_REM) /* % */
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OP (BINOP_MOD) /* mod (Knuth 1.2.4) */
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OP (BINOP_LSH) /* << */
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OP (BINOP_RSH) /* >> */
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OP (BINOP_LOGICAL_AND) /* && */
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OP (BINOP_LOGICAL_OR) /* || */
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OP (BINOP_BITWISE_AND) /* & */
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OP (BINOP_BITWISE_IOR) /* | */
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OP (BINOP_BITWISE_XOR) /* ^ */
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OP (BINOP_EQUAL) /* == */
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OP (BINOP_NOTEQUAL) /* != */
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OP (BINOP_LESS) /* < */
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OP (BINOP_GTR) /* > */
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OP (BINOP_LEQ) /* <= */
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OP (BINOP_GEQ) /* >= */
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OP (BINOP_REPEAT) /* @ */
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OP (BINOP_ASSIGN) /* = */
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OP (BINOP_COMMA) /* , */
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OP (BINOP_SUBSCRIPT) /* x[y] */
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OP (BINOP_EXP) /* Exponentiation */
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/* C++. */
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OP (BINOP_MIN) /* <? */
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OP (BINOP_MAX) /* >? */
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/* STRUCTOP_MEMBER is used for pointer-to-member constructs.
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X . * Y translates into X STRUCTOP_MEMBER Y. */
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OP (STRUCTOP_MEMBER)
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/* STRUCTOP_MPTR is used for pointer-to-member constructs
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when X is a pointer instead of an aggregate. */
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OP (STRUCTOP_MPTR)
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/* TYPE_INSTANCE is used when the user specifies a specific
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type instantiation for overloaded methods/functions.
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The format is:
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TYPE_INSTANCE num_types type0 ... typeN num_types TYPE_INSTANCE. */
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OP (TYPE_INSTANCE)
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/* end of C++. */
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/* For Modula-2 integer division DIV. */
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OP (BINOP_INTDIV)
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/* +=, -=, *=, and so on. The following exp_element is another opcode,
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a BINOP_, saying how to modify. Then comes another BINOP_ASSIGN_MODIFY,
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making three exp_elements in total. */
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OP (BINOP_ASSIGN_MODIFY)
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/* Modula-2 standard (binary) procedures. */
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OP (BINOP_VAL)
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/* Concatenate two operands, such as character strings or bitstrings.
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If the first operand is a integer expression, then it means concatenate
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the second operand with itself that many times. */
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OP (BINOP_CONCAT)
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/* This must be the highest BINOP_ value, for expprint.c. */
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OP (BINOP_END)
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/* Operates on three values computed by following subexpressions. */
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OP (TERNOP_COND) /* ?: */
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/* A sub-string/sub-array. Ada syntax: OP1(OP2..OP3). Return
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elements OP2 through OP3 of OP1. */
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OP (TERNOP_SLICE)
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/* Multidimensional subscript operator, such as Modula-2 x[a,b,...].
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The dimensionality is encoded in the operator, like the number of
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function arguments in OP_FUNCALL, I.E. <OP><dimension><OP>.
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The value of the first following subexpression is subscripted
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by each of the next following subexpressions, one per dimension. */
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OP (MULTI_SUBSCRIPT)
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/* The OP_... series take immediate following arguments.
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After the arguments come another OP_... (the same one)
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so that the grouping can be recognized from the end. */
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/* OP_LONG is followed by a type pointer in the next exp_element
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and the long constant value in the following exp_element.
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Then comes another OP_LONG.
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Thus, the operation occupies four exp_elements. */
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OP (OP_LONG)
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/* OP_DOUBLE is similar but takes a DOUBLEST constant instead of a
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long. */
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OP (OP_DOUBLE)
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/* OP_VAR_VALUE takes one struct block * in the following element,
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and one struct symbol * in the following exp_element, followed
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by another OP_VAR_VALUE, making four exp_elements. If the
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block is non-NULL, evaluate the symbol relative to the
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innermost frame executing in that block; if the block is NULL
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use the selected frame. */
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OP (OP_VAR_VALUE)
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/* OP_VAR_ENTRY_VALUE takes one struct symbol * in the following element,
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followed by another OP_VAR_ENTRY_VALUE, making three exp_elements.
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somename@entry may mean parameter value as present at the entry of the
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current function. Implemented via DW_OP_entry_value. */
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OP (OP_VAR_ENTRY_VALUE)
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/* OP_VAR_MSYM_VALUE takes one struct objfile * in the following
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element, and one struct minimal_symbol * in the following
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exp_element, followed by another OP_VAR_MSYM_VALUE, making four
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exp_elements. */
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OP (OP_VAR_MSYM_VALUE)
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/* OP_LAST is followed by an integer in the next exp_element.
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The integer is zero for the last value printed,
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or it is the absolute number of a history element.
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With another OP_LAST at the end, this makes three exp_elements. */
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OP (OP_LAST)
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/* OP_REGISTER is followed by a string in the next exp_element.
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This is the name of a register to fetch. */
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OP (OP_REGISTER)
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/* OP_INTERNALVAR is followed by an internalvar ptr in the next
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exp_element. With another OP_INTERNALVAR at the end, this
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makes three exp_elements. */
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OP (OP_INTERNALVAR)
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/* OP_FUNCALL is followed by an integer in the next exp_element.
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The integer is the number of args to the function call.
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That many plus one values from following subexpressions
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are used, the first one being the function.
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The integer is followed by a repeat of OP_FUNCALL,
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making three exp_elements. */
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OP (OP_FUNCALL)
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/* OP_OBJC_MSGCALL is followed by a string in the next exp_element
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and then an integer. The string is the selector string. The
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integer is the number of arguments to the message call. That
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many plus one values are used, the first one being the object
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pointer. This is an Objective C message. */
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OP (OP_OBJC_MSGCALL)
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/* This is EXACTLY like OP_FUNCALL but is semantically different.
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In F77, array subscript expressions, substring expressions and
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function calls are all exactly the same syntactically. They
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may only be disambiguated at runtime. Thus this operator,
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which indicates that we have found something of the form
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<name> ( <stuff> ). */
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OP (OP_F77_UNDETERMINED_ARGLIST)
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/* OP_COMPLEX takes a type in the following element, followed by another
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OP_COMPLEX, making three exp_elements. It is followed by two double
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args, and converts them into a complex number of the given type. */
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OP (OP_COMPLEX)
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/* OP_STRING represents a string constant.
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Its format is the same as that of a STRUCTOP, but the string
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data is just made into a string constant when the operation
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is executed. */
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OP (OP_STRING)
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/* OP_ARRAY creates an array constant out of the following subexpressions.
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It is followed by two exp_elements, the first containing an integer
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that is the lower bound of the array and the second containing another
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integer that is the upper bound of the array. The second integer is
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followed by a repeat of OP_ARRAY, making four exp_elements total.
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The bounds are used to compute the number of following subexpressions
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to consume, as well as setting the bounds in the created array constant.
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The type of the elements is taken from the type of the first subexp,
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and they must all match. */
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OP (OP_ARRAY)
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/* UNOP_CAST is followed by a type pointer in the next exp_element.
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With another UNOP_CAST at the end, this makes three exp_elements.
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It casts the value of the following subexpression. */
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OP (UNOP_CAST)
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/* Like UNOP_CAST, but the type is a subexpression. */
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OP (UNOP_CAST_TYPE)
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/* The C++ dynamic_cast operator. */
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OP (UNOP_DYNAMIC_CAST)
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/* The C++ reinterpret_cast operator. */
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OP (UNOP_REINTERPRET_CAST)
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/* UNOP_MEMVAL is followed by a type pointer in the next exp_element
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With another UNOP_MEMVAL at the end, this makes three exp_elements.
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It casts the contents of the word addressed by the value of the
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following subexpression. */
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OP (UNOP_MEMVAL)
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/* Like UNOP_MEMVAL, but the type is supplied as a subexpression. */
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OP (UNOP_MEMVAL_TYPE)
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/* UNOP_... operate on one value from a following subexpression
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and replace it with a result. They take no immediate arguments. */
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OP (UNOP_NEG) /* Unary - */
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OP (UNOP_LOGICAL_NOT) /* Unary ! */
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OP (UNOP_COMPLEMENT) /* Unary ~ */
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OP (UNOP_IND) /* Unary * */
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OP (UNOP_ADDR) /* Unary & */
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OP (UNOP_PREINCREMENT) /* ++ before an expression */
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OP (UNOP_POSTINCREMENT) /* ++ after an expression */
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OP (UNOP_PREDECREMENT) /* -- before an expression */
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OP (UNOP_POSTDECREMENT) /* -- after an expression */
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OP (UNOP_SIZEOF) /* Unary sizeof (followed by expression) */
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OP (UNOP_PLUS) /* Unary plus */
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OP (UNOP_CAP) /* Modula-2 standard (unary) procedures */
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OP (UNOP_CHR)
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OP (UNOP_ORD)
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OP (UNOP_ABS)
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OP (UNOP_FLOAT)
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OP (UNOP_HIGH)
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OP (UNOP_MAX)
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OP (UNOP_MIN)
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OP (UNOP_ODD)
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OP (UNOP_TRUNC)
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OP (OP_BOOL) /* Modula-2 builtin BOOLEAN type */
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OP (OP_M2_STRING) /* Modula-2 string constants */
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/* STRUCTOP_... operate on a value from a following subexpression
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by extracting a structure component specified by a string
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that appears in the following exp_elements (as many as needed).
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STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->".
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They differ only in the error message given in case the value is
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not suitable or the structure component specified is not found.
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The length of the string follows the opcode, followed by
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BYTES_TO_EXP_ELEM(length) elements containing the data of the
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string, followed by the length again and the opcode again. */
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OP (STRUCTOP_STRUCT)
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OP (STRUCTOP_PTR)
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/* Anonymous field access, e.g. "foo.3". Used in Rust. */
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OP (STRUCTOP_ANONYMOUS)
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/* C++: OP_THIS is just a placeholder for the class instance variable.
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It just comes in a tight (OP_THIS, OP_THIS) pair. */
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OP (OP_THIS)
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/* Objective C: "@selector" pseudo-operator. */
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OP (OP_OBJC_SELECTOR)
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/* OP_SCOPE surrounds a type name and a field name. The type
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name is encoded as one element, but the field name stays as
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a string, which, of course, is variable length. */
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OP (OP_SCOPE)
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/* OP_FUNC_STATIC_VAR refers to a function local static variable. The
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function is taken from the following subexpression. The length of
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the variable name as a string follows the opcode, followed by
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BYTES_TO_EXP_ELEM(length) elements containing the data of the
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string, followed by the length again and the opcode again.
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Note this is used by C++, but not C. The C parser handles local
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static variables in the parser directly. Also, this is only used
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in C++ if the function/method name is not quoted, like e.g.:
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p S:method()::var
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p S:method() const::var
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If the function/method is quoted like instead:
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p 'S:method() const'::var
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then the C-specific handling directly in the parser takes over (see
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"block/variable productions).
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Also, if the whole function+var is quoted like this:
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p 'S:method() const::var'
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then the whole quoted expression is interpreted as a single symbol
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name and we don't use OP_FUNC_STATIC_VAR either. In that case, the
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C++-specific symbol lookup routines take care of the
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function-local-static search. */
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OP (OP_FUNC_STATIC_VAR)
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/* OP_TYPE is for parsing types, and used with the "ptype" command
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so we can look up types that are qualified by scope, either with
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the GDB "::" operator, or the Modula-2 '.' operator. */
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OP (OP_TYPE)
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/* An un-looked-up identifier. */
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OP (OP_NAME)
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/* An Objective C Foundation Class NSString constant. */
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OP (OP_OBJC_NSSTRING)
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/* An array range operator (in Fortran 90, for "exp:exp", "exp:",
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":exp" and ":"). */
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OP (OP_RANGE)
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/* OP_DECFLOAT is followed by a type pointer in the next exp_element
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and a dec long constant value in the following exp_element.
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Then comes another OP_DECFLOAT. */
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OP (OP_DECFLOAT)
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/* OP_ADL_FUNC specifies that the function is to be looked up in an
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Argument Dependent manner (Koenig lookup). */
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OP (OP_ADL_FUNC)
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/* The typeof operator. This has one expression argument, which is
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evaluated solely for its type. */
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OP (OP_TYPEOF)
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/* The decltype operator. This has one expression argument, which is
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evaluated solely for its type. This is similar to typeof, but has
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slight different semantics. */
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OP (OP_DECLTYPE)
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/* The typeid operator. This has one expression argument. */
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OP (OP_TYPEID)
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/* This is used for the Rust [expr; N] form of array construction. It
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takes two expression arguments. */
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OP (OP_RUST_ARRAY)
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