--- /dev/null
+/****************************************************************************
+ * *
+ * GNAT COMPILER COMPONENTS *
+ * *
+ * S I G T R A M P *
+ * *
+ * Asm Implementation File *
+ * *
+ * Copyright (C) 2014, Free Software Foundation, Inc. *
+ * *
+ * GNAT is free software; you can redistribute it and/or modify it under *
+ * terms of the GNU General Public License as published by the Free Soft- *
+ * ware Foundation; either version 3, or (at your option) any later ver- *
+ * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
+ * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
+ * or FITNESS FOR A PARTICULAR PURPOSE. *
+ * *
+ * As a special exception under Section 7 of GPL version 3, you are granted *
+ * additional permissions described in the GCC Runtime Library Exception, *
+ * version 3.1, as published by the Free Software Foundation. *
+ * *
+ * In particular, you can freely distribute your programs built with the *
+ * GNAT Pro compiler, including any required library run-time units, using *
+ * any licensing terms of your choosing. See the AdaCore Software License *
+ * for full details. *
+ * *
+ * GNAT was originally developed by the GNAT team at New York University. *
+ * Extensive contributions were provided by Ada Core Technologies Inc. *
+ * *
+ ****************************************************************************/
+
+/******************************************************
+ * ARM-Android version of the __gnat_sigtramp service *
+ ******************************************************/
+
+#include "sigtramp.h"
+/* See sigtramp.h for a general explanation of functionality. */
+
+/* ----------------------
+ -- General comments --
+ ----------------------
+
+ Stubs are generated from toplevel asms,
+ The general idea is to establish CFA as the sigcontext
+ and state where to find the registers as offsets from there.
+
+ We support stubs for VxWorks and Android, providing unwind info for
+ common registers. We might need variants with support for floating
+ point or altivec registers as well at some point.
+
+ For Android it would be simpler to write this in Asm since there's only
+ one variant, but to keep it looking like the VxWorks stubs,
+ C is the choice for our toplevel interface.
+
+ Note that the registers we "restore" here are those to which we have
+ direct access through the system sigcontext structure, which includes
+ only a partial set of the non-volatiles ABI-wise. */
+
+/* -----------------------------------------
+ -- Protypes for our internal asm stubs --
+ -----------------------------------------
+
+ The registers are expected to be at SIGCONTEXT + 12 (reference the
+ sicontext structure in asm/sigcontext.h which describes the first
+ 3 * 4byte fields.) Even though our symbols will remain local, the
+ prototype claims "extern" and not "static" to prevent compiler complaints
+ about a symbol used but never defined. */
+
+/* sigtramp stub providing unwind info for common registers. */
+
+extern void __gnat_sigtramp_common
+ (int signo, void *siginfo, void *sigcontext,
+ __sigtramphandler_t * handler);
+
+void __gnat_sigtramp (int signo, void *si, void *sc,
+ __sigtramphandler_t * handler)
+ __attribute__((optimize(2)));
+
+void __gnat_sigtramp (int signo, void *si, void *ucontext,
+ __sigtramphandler_t * handler)
+{
+ struct sigcontext *mcontext = &((ucontext_t *) ucontext)->uc_mcontext;
+
+ __gnat_sigtramp_common (signo, si, mcontext, handler);
+}
+
+/* asm string construction helpers. */
+
+#define STR(TEXT) #TEXT
+/* stringify expanded TEXT, surrounding it with double quotes. */
+
+#define S(E) STR(E)
+/* stringify E, which will resolve as text but may contain macros
+ still to be expanded. */
+
+/* asm (TEXT) outputs <tab>TEXT. These facilitate the output of
+ multiline contents: */
+#define TAB(S) "\t" S
+#define CR(S) S "\n"
+
+#undef TCR
+#define TCR(S) TAB(CR(S))
+
+/* Trampoline body block
+ --------------------- */
+
+#define SIGTRAMP_BODY \
+CR("") \
+TCR("# Allocate frame and also save r2 which is the argument register") \
+TCR("# containing the sigcontext, so that we can restore it during") \
+TCR("# unwinding and thereby load the rest of the desired context.") \
+TCR("stmfd sp!, {r2, r3, lr}") \
+TCR("# The unwinder undo's these operations in reverse order so starting") \
+TCR("# from bottom, restore r2 from the current vsp location, move r2 into") \
+TCR("# the vsp, add 12 bytes to get the start of the register save area") \
+TCR("# then restore the 15 general purpose registers of the frame which") \
+TCR("# raised the signal.") \
+TCR(".save {r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15}") \
+TCR(".pad #12") \
+TCR(".movsp r2") \
+TCR(".save {r2}") \
+TCR("# Call the real handler. The signo, siginfo and sigcontext") \
+TCR("# arguments are the same as those we received in r0, r1 and r2.") \
+TCR("blx r3") \
+TCR("# Restore our callee-saved items, release our frame and return") \
+TCR("# (should never get here!).") \
+TCR("ldmfd sp, {r2, r3, pc}")
+
+/* Symbol definition block
+ ----------------------- */
+
+#define SIGTRAMP_START(SYM) \
+CR("# " S(SYM) " unwind trampoline") \
+TCR(".type " S(SYM) ", %function") \
+CR("") \
+CR(S(SYM) ":") \
+TCR(".fnstart")
+
+/* Symbol termination block
+ ------------------------ */
+
+#define SIGTRAMP_END(SYM) \
+CR(".fnend") \
+TCR(".size " S(SYM) ", .-" S(SYM))
+
+/*----------------------------
+ -- And now, the real code --
+ ---------------------------- */
+
+/* Text section start. The compiler isn't aware of that switch. */
+
+asm (".text\n"
+ TCR(".align 2"));
+
+/* sigtramp stub for common registers. */
+
+#define TRAMP_COMMON __gnat_sigtramp_common
+
+asm (SIGTRAMP_START(TRAMP_COMMON));
+asm (SIGTRAMP_BODY);
+asm (SIGTRAMP_END(TRAMP_COMMON));
projects / platform / upstream / linaro-gcc.git / commitdiff