1 // SPDX-License-Identifier: GPL-2.0-only
3  * Copyright 2011-2017 by the PaX Team <pageexec@freemail.hu>
13  *  - after alloca();
14  *  - for the functions with a stack frame size greater than or equal
15  *     to the "track-min-size" plugin parameter.
22  *  - use fprintf() to stderr, debug_generic_expr(), debug_gimple_stmt(),
24  *  - add "-fdump-tree-all -fdump-rtl-all" to the plugin CFLAGS in
25  *     Makefile.gcc-plugins to see the verbose dumps of the gcc passes;
26  *  - use gcc -E to understand the preprocessing shenanigans;
27  *  - use gcc with enabled CFG/GIMPLE/SSA verification (--enable-checking).
30 #include "gcc-common.h"
34 static int track_frame_size = -1;
42  * they point to the garbage-collected memory.
48 	.help = "track-min-size=nn\ttrack stack for functions with a stack frame size >= nn bytes\n"
74 			gimple_call, bb->count,  in add_stack_tracking_gcall()
97 		if (DECL_NAME_LENGTH(var) != sizeof("current_stack_pointer") - 1)  in get_current_stack_pointer_decl()
127 	 * This constraint is taken into account during gcc shrink-wrapping  in add_stack_tracking_gasm()
157 	 * caller-saved registers in the functions from which we will remove  in add_stack_tracking()
158 	 * stackleak_track_stack() call during the stackleak_cleanup pass.  in add_stack_tracking()
186 	 * Loop through the GIMPLE statements in each of cfun basic blocks.  in stackleak_instrument_execute()
248 				(bb->flags & BB_IRREDUCIBLE_LOOP)); */  in stackleak_instrument_execute()
273 	 * Find stackleak_track_stack() calls. Loop through the chain of insns,  in remove_stack_tracking_gcall()
343 	 * Find stackleak_track_stack() asm calls. Loop through the chain of  in remove_stack_tracking_gasm()
351 	 *  (clobber (reg:CC 17 flags)) ]) -1 (nil))  in remove_stack_tracking_gasm()
404 	 *   expand_stack_vars() for runtime alignment of constant-sized stack  in stackleak_cleanup_execute()
405 	 *   variables. That caused cfun->calls_alloca to be set for functions  in stackleak_cleanup_execute()
410 	if (cfun->calls_alloca) {  in stackleak_cleanup_execute()
434  * https://gcc.gnu.org/onlinedocs/gccint/Constant-expressions.html
495  * Pass gate function is a predicate function that gets executed before the
496  * corresponding pass. If the return value is 'true' the pass gets executed,
509 #include "gcc-generate-gimple-pass.h"
518 #include "gcc-generate-rtl-pass.h"
528 	const char * const plugin_name = plugin_info->base_name;  in plugin_init()
529 	const int argc = plugin_info->argc;  in plugin_init()
530 	const struct plugin_argument * const argv = plugin_info->argv;  in plugin_init()
533 	/* Extra GGC root tables describing our GTY-ed data */  in plugin_init()
546 	 * The stackleak_instrument pass should be executed before the  in plugin_init()
547 	 * "optimized" pass, which is the control flow graph cleanup that is  in plugin_init()
549 	 * versions of the plugin this new pass was inserted before the  in plugin_init()
550 	 * "tree_profile" pass, which is currently called "profile".  in plugin_init()
556 	 * The stackleak_cleanup pass should be executed before the "*free_cfg"  in plugin_init()
557 	 * pass. It's the moment when the stack frame size is already final,  in plugin_init()
559 	 * machine-dependent code transformations are not done.  in plugin_init()
570 		if (!strcmp(argv[i].key, "track-min-size")) {  in plugin_init()
572 				error(G_("no value supplied for option '-fplugin-arg-%s-%s'"),  in plugin_init()
579 				error(G_("invalid option argument '-fplugin-arg-%s-%s=%s'"),  in plugin_init()
585 				error(G_("no value supplied for option '-fplugin-arg-%s-%s'"),  in plugin_init()
597 			error(G_("unknown option '-fplugin-arg-%s-%s'"),  in plugin_init()
622 	 * Hook into the Pass Manager to register new gcc passes.  in plugin_init()
624 	 * The stack frame size info is available only at the last RTL pass,  in plugin_init()