the "compile" command

This final patch adds the new "compile" command and subcommands, and
all the machinery needed to make it work.

A shared library supplied by gcc is used for all communications with
gcc.  Types and most aspects of symbols are provided directly by gdb
to the compiler using this library.

gdb provides some information about the user's code using plain text.
Macros are emitted this way, and DWARF location expressions (and
bounds for VLA) are compiled to C code.

This hybrid approach was taken because, on the one hand, it is better
to provide global declarations and such on demand; but on the other
hand, for local variables, translating DWARF location expressions to C
was much simpler than exporting a full compiler API to gdb -- the same
result, only easier to implement, understand, and debug.

In the ordinary mode, the user's expression is wrapped in a dummy
function.  After compilation, gdb inserts the resulting object code
into the inferior, then calls this function.

Access to local variables is provided by noting which registers are
used by location expressions, and passing a structure of register
values into the function.  Writes to registers are supported by
copying out these values after the function returns.

This approach was taken so that we could eventually implement other
more interesting features based on this same infrastructure; for
example, we're planning to investigate inferior-side breakpoint
conditions.

gdb/ChangeLog
2014-12-12  Phil Muldoon  <pmuldoon@redhat.com>
	    Jan Kratochvil  <jan.kratochvil@redhat.com>
	    Tom Tromey  <tromey@redhat.com>

	* NEWS: Update.
	* symtab.h (struct symbol_computed_ops) <generate_c_location>: New
	field.
	* p-lang.c (pascal_language_defn): Update.
	* opencl-lang.c (opencl_language_defn): Update.
	* objc-lang.c (objc_language_defn): Update.
	* m2-lang.c (m2_language_defn): Update.
	* language.h (struct language_defn) <la_get_compile_instance,
	la_compute_program>: New fields.
	* language.c (unknown_language_defn, auto_language_defn)
	(local_language_defn): Update.
	* jv-lang.c (java_language_defn): Update.
	* go-lang.c (go_language_defn): Update.
	* f-lang.c (f_language_defn): Update.
	* dwarf2loc.h (dwarf2_compile_property_to_c): Declare.
	* dwarf2loc.c (dwarf2_compile_property_to_c)
	(locexpr_generate_c_location, loclist_generate_c_location): New
	functions.
	(dwarf2_locexpr_funcs, dwarf2_loclist_funcs): Update.
	* defs.h (enum compile_i_scope_types): New.
	(enum command_control_type) <compile_control>: New constant.
	(struct command_line) <control_u>: New field.
	* d-lang.c (d_language_defn): Update.
	* compile/compile.c: New file.
	* compile/compile-c-support.c: New file.
	* compile/compile-c-symbols.c: New file.
	* compile/compile-c-types.c: New file.
	* compile/compile.h: New file.
	* compile/compile-internal.h: New file.
	* compile/compile-loc2c.c: New file.
	* compile/compile-object-load.c: New file.
	* compile/compile-object-load.h: New file.
	* compile/compile-object-run.c: New file.
	* compile/compile-object-run.h: New file.
	* cli/cli-script.c (multi_line_command_p, print_command_lines)
	(execute_control_command, process_next_line)
	(recurse_read_control_structure): Handle compile_control.
	* c-lang.h (c_get_compile_context, c_compute_program): Declare.
	* c-lang.c (c_language_defn, cplus_language_defn)
	(asm_language_defn, minimal_language_defn): Update.
	* ada-lang.c (ada_language_defn): Update.
	* Makefile.in (SUBDIR_GCC_COMPILE_OBS, SUBDIR_GCC_COMPILE_SRCS):
	New variables.
	(SFILES): Add SUBDIR_GCC_COMPILE_SRCS.
	(HFILES_NO_SRCDIR): Add compile.h.
	(COMMON_OBS): Add SUBDIR_GCC_COMPILE_OBS.
	(INIT_FILES): Add SUBDIR_GCC_COMPILE_SRCS.
	(compile.o, compile-c-types.o, compile-c-symbols.o)
	(compile-object-load.o, compile-object-run.o, compile-loc2c.o)
	(compile-c-support.o): New targets.

gdb/doc/ChangeLog
2014-12-12  Phil Muldoon  <pmuldoon@redhat.com>
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.texinfo (Altering): Update.
	(Compiling and Injecting Code): New node.

gdb/testsuite/ChangeLog
2014-12-12  Phil Muldoon  <pmuldoon@redhat.com>
	    Jan Kratochvil  <jan.kratochvil@redhat.com>
	    Tom Tromey  <tromey@redhat.com>

	* configure.ac: Add gdb.compile/.
	* configure: Regenerate.
	* gdb.compile/Makefile.in: New file.
	* gdb.compile/compile-ops.exp: New file.
	* gdb.compile/compile-ops.c: New file.
	* gdb.compile/compile-tls.c: New file.
	* gdb.compile/compile-tls.exp: New file.
	* gdb.compile/compile-constvar.S: New file.
	* gdb.compile/compile-constvar.c: New file.
	* gdb.compile/compile-mod.c: New file.
	* gdb.compile/compile-nodebug.c: New file.
	* gdb.compile/compile-setjmp-mod.c: New file.
	* gdb.compile/compile-setjmp.c: New file.
	* gdb.compile/compile-setjmp.exp: New file.
	* gdb.compile/compile-shlib.c: New file.
	* gdb.compile/compile.c: New file.
	* gdb.compile/compile.exp: New file.
	* lib/gdb.exp (skip_compile_feature_tests): New proc.

1 files changed, 95 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.compile/compile-constvar.S b/gdb/testsuite/gdb.compile/compile-constvar.S
new file mode 100644
index 0000000..55d81bc
--- /dev/null
+++ b/gdb/testsuite/gdb.compile/compile-constvar.S
@@ -0,0 +1,95 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2014 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+// gcc -o gdb.base/compile-constvar.S -dA -S -g gdb.base/compile-constvar.c
+
+	.file	"compile-constvar.c"
+	.file 1 "gdb.base/compile-constvar.c"
+	.section	.debug_info,"",@progbits
+.Ldebug_info0:
+	.long	.Lend-.Lstart	# Length of Compilation Unit Info
+.Lstart:
+	.value	0x4	# DWARF version number
+	.long	.Ldebug_abbrev0	# Offset Into Abbrev. Section
+	.byte	0x8	# Pointer Size (in bytes)
+	.uleb128 0x1	# (DIE (0xb) DW_TAG_compile_unit)
+	.long	.LASF0	# DW_AT_producer: "GNU C 4.8.2 20131212 (Red Hat 4.8.2-7) -mtune=generic -march=x86-64 -g"
+	.byte	0x1	# DW_AT_language
+	.long	.LASF1	# DW_AT_name: "gdb.base/compile-constvar.c"
+	.long	.LASF2	# DW_AT_comp_dir: "/home/jkratoch/redhat/gdb-gdbjit/gdb/testsuite"
+	.uleb128 0x2	# (DIE (0x1d) DW_TAG_variable)
+	.long	.LASF3	# DW_AT_name: "constvar"
+	.long	.Linttype-.Ldebug_info0	# DW_AT_type
+			# DW_AT_external
+	.byte	0x3	# DW_AT_const_value
+.Linttype:
+	.uleb128 0x3	# (DIE (0x32) DW_TAG_base_type)
+	.byte	0x4	# DW_AT_byte_size
+	.byte	0x5	# DW_AT_encoding
+	.ascii "int\0"	# DW_AT_name
+	.byte	0	# end of children of DIE 0xb
+.Lend:
+	.section	.debug_abbrev,"",@progbits
+.Ldebug_abbrev0:
+	.uleb128 0x1	# (abbrev code)
+	.uleb128 0x11	# (TAG: DW_TAG_compile_unit)
+	.byte	0x1	# DW_children_yes
+	.uleb128 0x25	# (DW_AT_producer)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x13	# (DW_AT_language)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x1b	# (DW_AT_comp_dir)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.byte	0
+	.byte	0
+	.uleb128 0x2	# (abbrev code)
+	.uleb128 0x34	# (TAG: DW_TAG_variable)
+	.byte	0	# DW_children_no
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x49	# (DW_AT_type)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x1c	# (DW_AT_const_value)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.byte	0
+	.byte	0
+	.uleb128 0x3	# (abbrev code)
+	.uleb128 0x24	# (TAG: DW_TAG_base_type)
+	.byte	0	# DW_children_no
+	.uleb128 0xb	# (DW_AT_byte_size)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3e	# (DW_AT_encoding)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0x8	# (DW_FORM_string)
+	.byte	0
+	.byte	0
+	.byte	0
+	.section	.debug_str,"MS",@progbits,1
+.LASF1:
+	.string	"gdb.base/compile-constvar.c"
+.LASF3:
+	.string	"constvar"
+.LASF2:
+	.string	""
+.LASF0:
+	.string	"GNU C 4.8.2 20131212 (Red Hat 4.8.2-7) -mtune=generic -march=x86-64 -g"
+	.ident	"GCC: (GNU) 4.8.2 20131212 (Red Hat 4.8.2-7)"