/*
 * tramp-amd64.c: JIT trampoline code for amd64
 *
 * Authors:
 *   Dietmar Maurer (dietmar@ximian.com)
 *   Zoltan Varga (vargaz@gmail.com)
 *
 * (C) 2001 Ximian, Inc.
 */

#include <config.h>
#include <glib.h>

#include <mono/metadata/appdomain.h>
#include <mono/metadata/marshal.h>
#include <mono/metadata/tabledefs.h>
#include <mono/metadata/mono-debug-debugger.h>
#include <mono/metadata/monitor.h>
#include <mono/arch/amd64/amd64-codegen.h>

#ifdef HAVE_VALGRIND_MEMCHECK_H
#include <valgrind/memcheck.h>
#endif

#include "mini.h"
#include "mini-amd64.h"

#define IS_REX(inst) (((inst) >= 0x40) && ((inst) <= 0x4f))

static guint8* nullified_class_init_trampoline;

/*
 * mono_arch_get_unbox_trampoline:
 * @gsctx: the generic sharing context
 * @m: method pointer
 * @addr: pointer to native code for @m
 *
 * when value type methods are called through the vtable we need to unbox the
 * this argument. This method returns a pointer to a trampoline which does
 * unboxing before calling the method
 */
gpointer
mono_arch_get_unbox_trampoline (MonoGenericSharingContext *gsctx, MonoMethod *m, gpointer addr)
{
	guint8 *code, *start;
	int this_reg;

	MonoDomain *domain = mono_domain_get ();

	this_reg = mono_arch_get_this_arg_reg (mono_method_signature (m), gsctx, NULL);

	start = code = mono_domain_code_reserve (domain, 20);

	amd64_alu_reg_imm (code, X86_ADD, this_reg, sizeof (MonoObject));
	/* FIXME: Optimize this */
	amd64_mov_reg_imm (code, AMD64_RAX, addr);
	amd64_jump_reg (code, AMD64_RAX);
	g_assert ((code - start) < 20);

	mono_arch_flush_icache (start, code - start);

	return start;
}

/*
 * mono_arch_get_static_rgctx_trampoline:
 *
 *   Create a trampoline which sets RGCTX_REG to MRGCTX, then jumps to ADDR.
 */
gpointer
mono_arch_get_static_rgctx_trampoline (MonoMethod *m, MonoMethodRuntimeGenericContext *mrgctx, gpointer addr)
{
	guint8 *code, *start;
	int buf_len;

	MonoDomain *domain = mono_domain_get ();

#ifdef MONO_ARCH_NOMAP32BIT
	buf_len = 32;
#else
	/* AOTed code could still have a non-32 bit address */
	if ((((guint64)addr) >> 32) == 0)
		buf_len = 16;
	else
		buf_len = 30;
#endif

	start = code = mono_domain_code_reserve (domain, buf_len);

	amd64_mov_reg_imm (code, MONO_ARCH_RGCTX_REG, mrgctx);
	amd64_jump_code (code, addr);
	g_assert ((code - start) < buf_len);

	mono_arch_flush_icache (start, code - start);

	return start;
}

/*
 * mono_arch_patch_callsite:
 *
 *   Patch the callsite whose address is given by ORIG_CODE so it calls ADDR. ORIG_CODE
 * points to the pc right after the call.
 */
void
mono_arch_patch_callsite (guint8 *method_start, guint8 *orig_code, guint8 *addr)
{
	guint8 *code;
	guint8 buf [16];
	gboolean can_write = mono_breakpoint_clean_code (method_start, orig_code, 14, buf, sizeof (buf));

	code = buf + 14;

	if (((code [-13] == 0x49) && (code [-12] == 0xbb)) || (code [-5] == 0xe8)) {
		if (code [-5] != 0xe8) {
			if (can_write) {
				InterlockedExchangePointer ((gpointer*)(orig_code - 11), addr);
#ifdef HAVE_VALGRIND_MEMCHECK_H
				VALGRIND_DISCARD_TRANSLATIONS (orig_code - 11, sizeof (gpointer));
#endif
			}
		} else {
			if ((((guint64)(addr)) >> 32) != 0) {
				/* Print some diagnostics */
				MonoJitInfo *ji = mono_jit_info_table_find (mono_domain_get (), (char*)orig_code);
				if (ji)
					fprintf (stderr, "At %s, offset 0x%zx\n", mono_method_full_name (ji->method, TRUE), (guint8*)orig_code - (guint8*)ji->code_start);
				fprintf (stderr, "Addr: %p\n", addr);
				ji = mono_jit_info_table_find (mono_domain_get (), (char*)addr);
				if (ji)
					fprintf (stderr, "Callee: %s\n", mono_method_full_name (ji->method, TRUE));
				g_assert_not_reached ();
			}
			g_assert ((((guint64)(orig_code)) >> 32) == 0);
			if (can_write) {
				InterlockedExchange ((gint32*)(orig_code - 4), ((gint64)addr - (gint64)orig_code));
#ifdef HAVE_VALGRIND_MEMCHECK_H
				VALGRIND_DISCARD_TRANSLATIONS (orig_code - 5, 4);
#endif
			}
		}
	}
	else if ((code [-7] == 0x41) && (code [-6] == 0xff) && (code [-5] == 0x15)) {
		/* call *<OFFSET>(%rip) */
		gpointer *got_entry = (gpointer*)((guint8*)orig_code + (*(guint32*)(orig_code - 4)));
		if (can_write) {
			InterlockedExchangePointer (got_entry, addr);
#ifdef HAVE_VALGRIND_MEMCHECK_H
			VALGRIND_DISCARD_TRANSLATIONS (orig_code - 5, sizeof (gpointer));
#endif
		}
	}
}

void
mono_arch_patch_plt_entry (guint8 *code, guint8 *addr)
{
	gint32 disp;
	gpointer *plt_jump_table_entry;

	/* A PLT entry: jmp *<DISP>(%rip) */
	g_assert (code [0] == 0xff);
	g_assert (code [1] == 0x25);

	disp = *(gint32*)(code + 2);

	plt_jump_table_entry = (gpointer*)(code + 6 + disp);

	InterlockedExchangePointer (plt_jump_table_entry, addr);
}

void
mono_arch_nullify_class_init_trampoline (guint8 *code, gssize *regs)
{
	guint8 buf [16];
	gboolean can_write = mono_breakpoint_clean_code (NULL, code, 7, buf, sizeof (buf));

	if (!can_write)
		return;

	code -= 3;

	/* 
	 * A given byte sequence can match more than case here, so we have to be
	 * really careful about the ordering of the cases. Longer sequences
	 * come first.
	 */
	if ((code [-4] == 0x41) && (code [-3] == 0xff) && (code [-2] == 0x15)) {
		gpointer *vtable_slot;

		/* call *<OFFSET>(%rip) */
		vtable_slot = mono_get_vcall_slot_addr (code + 3, (gpointer*)regs);
		g_assert (vtable_slot);

		*vtable_slot = nullified_class_init_trampoline;
	} else if (code [-2] == 0xe8) {
		/* call <TARGET> */
		//guint8 *buf = code - 2;

		/* 
		 * It would be better to replace the call with nops, but that doesn't seem
		 * to work on SMP machines even when the whole call is inside a cache line.
		 * Patching the call address seems to work.
		 */
		/*
		buf [0] = 0x66;
		buf [1] = 0x66;
		buf [2] = 0x90;
		buf [3] = 0x66;
		buf [4] = 0x90;
		*/

		mono_arch_patch_callsite (code - 2, code - 2 + 5, nullified_class_init_trampoline);
	} else if ((code [0] == 0x41) && (code [1] == 0xff)) {
		/* call <REG> */
		/* happens on machines without MAP_32BIT like freebsd */
		/* amd64_set_reg_template is 10 bytes long */
		guint8* buf = code - 10;

		/* FIXME: Make this thread safe */
		/* Padding code suggested by the AMD64 Opt Manual */
		buf [0] = 0x66;
		buf [1] = 0x66;
		buf [2] = 0x66;
		buf [3] = 0x90;
		buf [4] = 0x66;
		buf [5] = 0x66;
		buf [6] = 0x66;
		buf [7] = 0x90;
		buf [8] = 0x66;
		buf [9] = 0x66;
		buf [10] = 0x90;
		buf [11] = 0x66;
		buf [12] = 0x90;
	} else if (code [0] == 0x90 || code [0] == 0xeb || code [0] == 0x66) {
		/* Already changed by another thread */
		;
	} else {
		printf ("Invalid trampoline sequence: %x %x %x %x %x %x %x\n", code [0], code [1], code [2], code [3],
			code [4], code [5], code [6]);
		g_assert_not_reached ();
	}
}

void
mono_arch_nullify_plt_entry (guint8 *code)
{
	if (mono_aot_only && !nullified_class_init_trampoline)
		nullified_class_init_trampoline = mono_aot_get_named_code ("nullified_class_init_trampoline");

	mono_arch_patch_plt_entry (code, nullified_class_init_trampoline);
}

guchar*
mono_arch_create_trampoline_code (MonoTrampolineType tramp_type)
{
	MonoJumpInfo *ji;
	guint32 code_size;
	guchar *code;
	GSList *unwind_ops, *l;

	code = mono_arch_create_trampoline_code_full (tramp_type, &code_size, &ji, &unwind_ops, FALSE);

	mono_save_trampoline_xdebug_info ("<generic_trampoline>", code, code_size, unwind_ops);

	for (l = unwind_ops; l; l = l->next)
		g_free (l->data);
	g_slist_free (unwind_ops);

	return code;
}

guchar*
mono_arch_create_trampoline_code_full (MonoTrampolineType tramp_type, guint32 *code_size, MonoJumpInfo **ji, GSList **out_unwind_ops, gboolean aot)
{
	guint8 *buf, *code, *tramp, *br [2], *r11_save_code, *after_r11_save_code;
	int i, lmf_offset, offset, res_offset, arg_offset, rax_offset, tramp_offset, saved_regs_offset;
	int saved_fpregs_offset, rbp_offset, framesize, orig_rsp_to_rbp_offset, cfa_offset;
	gboolean has_caller;
	GSList *unwind_ops = NULL;

	if (tramp_type == MONO_TRAMPOLINE_JUMP)
		has_caller = FALSE;
	else
		has_caller = TRUE;

	code = buf = mono_global_codeman_reserve (538);

	*ji = NULL;

	framesize = 538 + sizeof (MonoLMF);
	framesize = (framesize + (MONO_ARCH_FRAME_ALIGNMENT - 1)) & ~ (MONO_ARCH_FRAME_ALIGNMENT - 1);

	orig_rsp_to_rbp_offset = 0;
	r11_save_code = code;
	/* Reserve 5 bytes for the mov_membase_reg to save R11 */
	code += 5;
	after_r11_save_code = code;

	// CFA = sp + 16 (the trampoline address is on the stack)
	cfa_offset = 16;
	mono_add_unwind_op_def_cfa (unwind_ops, code, buf, AMD64_RSP, 16);
	// IP saved at CFA - 8
	mono_add_unwind_op_offset (unwind_ops, code, buf, AMD64_RIP, -8);

	/* Pop the return address off the stack */
	amd64_pop_reg (code, AMD64_R11);
	orig_rsp_to_rbp_offset += 8;

	cfa_offset -= 8;
	mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);

	/* 
	 * Allocate a new stack frame
	 */
	amd64_push_reg (code, AMD64_RBP);
	cfa_offset += 8;
	mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
	mono_add_unwind_op_offset (unwind_ops, code, buf, AMD64_RBP, - cfa_offset);

	orig_rsp_to_rbp_offset -= 8;
	amd64_mov_reg_reg (code, AMD64_RBP, AMD64_RSP, 8);
	mono_add_unwind_op_def_cfa_reg (unwind_ops, code, buf, AMD64_RBP);
	amd64_alu_reg_imm (code, X86_SUB, AMD64_RSP, framesize);

	offset = 0;
	rbp_offset = - offset;

	offset += 8;
	rax_offset = - offset;

	offset += 8;
	tramp_offset = - offset;

	offset += 8;
	arg_offset = - offset;

	/* Compute the trampoline address from the return address */
	if (aot) {
		/* 7 = length of call *<offset>(rip) */
		amd64_alu_reg_imm (code, X86_SUB, AMD64_R11, 7);
	} else {
		/* 5 = length of amd64_call_membase () */
		amd64_alu_reg_imm (code, X86_SUB, AMD64_R11, 5);
	}
	amd64_mov_membase_reg (code, AMD64_RBP, tramp_offset, AMD64_R11, 8);

	offset += 8;
	res_offset = - offset;

	/* Save all registers */

	offset += AMD64_NREG * 8;
	saved_regs_offset = - offset;
	for (i = 0; i < AMD64_NREG; ++i) {
		if (i == AMD64_RBP) {
			/* RAX is already saved */
			amd64_mov_reg_membase (code, AMD64_RAX, AMD64_RBP, rbp_offset, 8);
			amd64_mov_membase_reg (code, AMD64_RBP, saved_regs_offset + (i * 8), AMD64_RAX, 8);
		} else if (i != AMD64_R11) {
			amd64_mov_membase_reg (code, AMD64_RBP, saved_regs_offset + (i * 8), i, 8);
		} else {
			/* We have to save R11 right at the start of
			   the trampoline code because it's used as a
			   scratch register */
			amd64_mov_membase_reg (r11_save_code, AMD64_RSP, saved_regs_offset + orig_rsp_to_rbp_offset + (i * 8), i, 8);
			g_assert (r11_save_code == after_r11_save_code);
		}
	}
	offset += 8 * 8;
	saved_fpregs_offset = - offset;
	for (i = 0; i < 8; ++i)
		amd64_movsd_membase_reg (code, AMD64_RBP, saved_fpregs_offset + (i * 8), i);

	if (tramp_type != MONO_TRAMPOLINE_GENERIC_CLASS_INIT &&
			tramp_type != MONO_TRAMPOLINE_MONITOR_ENTER &&
			tramp_type != MONO_TRAMPOLINE_MONITOR_EXIT) {
		/* Obtain the trampoline argument which is encoded in the instruction stream */
		if (aot) {
			/* Load the GOT offset */
			amd64_mov_reg_membase (code, AMD64_R11, AMD64_RBP, tramp_offset, 8);
			amd64_mov_reg_membase (code, AMD64_RAX, AMD64_R11, 7, 4);
			/* Compute the address of the GOT slot */
			amd64_alu_reg_reg_size (code, X86_ADD, AMD64_R11, AMD64_RAX, 8);
			/* Load the value */
			amd64_mov_reg_membase (code, AMD64_R11, AMD64_R11, 0, 8);
		} else {			
			amd64_mov_reg_membase (code, AMD64_R11, AMD64_RBP, tramp_offset, 8);
			amd64_mov_reg_membase (code, AMD64_RAX, AMD64_R11, 5, 1);
			amd64_widen_reg (code, AMD64_RAX, AMD64_RAX, TRUE, FALSE);
			amd64_alu_reg_imm_size (code, X86_CMP, AMD64_RAX, 4, 1);
			br [0] = code;
			x86_branch8 (code, X86_CC_NE, 6, FALSE);
			/* 32 bit immediate */
			amd64_mov_reg_membase (code, AMD64_R11, AMD64_R11, 6, 4);
			br [1] = code;
			x86_jump8 (code, 10);
			/* 64 bit immediate */
			mono_amd64_patch (br [0], code);
			amd64_mov_reg_membase (code, AMD64_R11, AMD64_R11, 6, 8);
			mono_amd64_patch (br [1], code);
		}
		amd64_mov_membase_reg (code, AMD64_RBP, arg_offset, AMD64_R11, 8);
	} else {
		amd64_mov_reg_membase (code, AMD64_R11, AMD64_RBP, saved_regs_offset + (MONO_AMD64_ARG_REG1 * 8), 8);
		amd64_mov_membase_reg (code, AMD64_RBP, arg_offset, AMD64_R11, 8);
	}

	/* Save LMF begin */

	offset += sizeof (MonoLMF);
	lmf_offset = - offset;

	/* Save ip */
	if (has_caller)
		amd64_mov_reg_membase (code, AMD64_R11, AMD64_RBP, 8, 8);
	else
		amd64_mov_reg_imm (code, AMD64_R11, 0);
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, rip), AMD64_R11, 8);
	/* Save fp */
	amd64_mov_reg_membase (code, AMD64_R11, AMD64_RSP, framesize, 8);
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, rbp), AMD64_R11, 8);
	/* Save sp */
	amd64_mov_reg_reg (code, AMD64_R11, AMD64_RSP, 8);
	amd64_alu_reg_imm (code, X86_ADD, AMD64_R11, framesize + 16);
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, rsp), AMD64_R11, 8);
	/* Save method */
	if (tramp_type == MONO_TRAMPOLINE_JIT || tramp_type == MONO_TRAMPOLINE_JUMP) {
		amd64_mov_reg_membase (code, AMD64_R11, AMD64_RBP, arg_offset, 8);
		amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, method), AMD64_R11, 8);
	} else {
		amd64_mov_membase_imm (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, method), 0, 8);
	}
	/* Save callee saved regs */
#ifdef PLATFORM_WIN32
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, rdi), AMD64_RDI, 8);
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, rsi), AMD64_RSI, 8);
#endif
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, rbx), AMD64_RBX, 8);
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, r12), AMD64_R12, 8);
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, r13), AMD64_R13, 8);
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, r14), AMD64_R14, 8);
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, r15), AMD64_R15, 8);

	if (aot) {
		*ji = mono_patch_info_list_prepend (*ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_get_lmf_addr");
		amd64_mov_reg_membase (code, AMD64_R11, AMD64_RIP, 0, 8);
	} else {
		amd64_mov_reg_imm (code, AMD64_R11, mono_get_lmf_addr);
	}
	amd64_call_reg (code, AMD64_R11);

	/* Save lmf_addr */
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, lmf_addr), AMD64_RAX, 8);
	/* Save previous_lmf */
	/* Set the lowest bit to 1 to signal that this LMF has the ip field set */
	amd64_mov_reg_membase (code, AMD64_R11, AMD64_RAX, 0, 8);
	amd64_alu_reg_imm_size (code, X86_ADD, AMD64_R11, 1, 8);
	amd64_mov_membase_reg (code, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, previous_lmf), AMD64_R11, 8);
	/* Set new lmf */
	amd64_lea_membase (code, AMD64_R11, AMD64_RBP, lmf_offset);
	amd64_mov_membase_reg (code, AMD64_RAX, 0, AMD64_R11, 8);

	/* Save LMF end */

	/* Arg1 is the pointer to the saved registers */
	amd64_lea_membase (code, AMD64_ARG_REG1, AMD64_RBP, saved_regs_offset);

	/* Arg2 is the address of the calling code */
	if (has_caller)
		amd64_mov_reg_membase (code, AMD64_ARG_REG2, AMD64_RBP, 8, 8);
	else
		amd64_mov_reg_imm (code, AMD64_ARG_REG2, 0);

	/* Arg3 is the method/vtable ptr */
	amd64_mov_reg_membase (code, AMD64_ARG_REG3, AMD64_RBP, arg_offset, 8);

	/* Arg4 is the trampoline address */
	amd64_mov_reg_membase (code, AMD64_ARG_REG4, AMD64_RBP, tramp_offset, 8);

	if (aot) {
		char *icall_name = g_strdup_printf ("trampoline_func_%d", tramp_type);
		*ji = mono_patch_info_list_prepend (*ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, icall_name);
		amd64_mov_reg_membase (code, AMD64_RAX, AMD64_RIP, 0, 8);
	} else {
		tramp = (guint8*)mono_get_trampoline_func (tramp_type);
		amd64_mov_reg_imm (code, AMD64_RAX, tramp);
	}
	amd64_call_reg (code, AMD64_RAX);

	/* Check for thread interruption */
	/* This is not perf critical code so no need to check the interrupt flag */
	/* 
	 * Have to call the _force_ variant, since there could be a protected wrapper on the top of the stack.
	 */
	amd64_mov_membase_reg (code, AMD64_RBP, res_offset, AMD64_RAX, 8);
	if (aot) {
		*ji = mono_patch_info_list_prepend (*ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_thread_force_interruption_checkpoint");
		amd64_mov_reg_membase (code, AMD64_RAX, AMD64_RIP, 0, 8);
	} else {
		amd64_mov_reg_imm (code, AMD64_RAX, (guint8*)mono_thread_force_interruption_checkpoint);
	}
	amd64_call_reg (code, AMD64_RAX);
	amd64_mov_reg_membase (code, AMD64_RAX, AMD64_RBP, res_offset, 8);	

	/* Restore LMF */

	amd64_mov_reg_membase (code, AMD64_RCX, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, previous_lmf), 8);
	amd64_alu_reg_imm_size (code, X86_SUB, AMD64_RCX, 1, 8);
	amd64_mov_reg_membase (code, AMD64_R11, AMD64_RBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, lmf_addr), 8);
	amd64_mov_membase_reg (code, AMD64_R11, 0, AMD64_RCX, 8);

	/* 
	 * Save rax to the stack, after the leave instruction, this will become part of
	 * the red zone.
	 */
	amd64_mov_membase_reg (code, AMD64_RBP, rax_offset, AMD64_RAX, 8);

	/* Restore argument registers, r10 (needed to pass rgctx to
	   static shared generic methods), r11 (imt register for
	   interface calls), and rax (needed for direct calls to C vararg functions). */
	for (i = 0; i < AMD64_NREG; ++i)
		if (AMD64_IS_ARGUMENT_REG (i) || i == AMD64_R10 || i == AMD64_R11 || i == AMD64_RAX)
			amd64_mov_reg_membase (code, i, AMD64_RBP, saved_regs_offset + (i * 8), 8);

	for (i = 0; i < 8; ++i)
		amd64_movsd_reg_membase (code, i, AMD64_RBP, saved_fpregs_offset + (i * 8));

	/* Restore stack */
	amd64_leave (code);

	if (MONO_TRAMPOLINE_TYPE_MUST_RETURN (tramp_type)) {
		/* Load result */
		amd64_mov_reg_membase (code, AMD64_RAX, AMD64_RSP, rax_offset - 0x8, 8);
		amd64_ret (code);
	} else {
		/* call the compiled method using the saved rax */
		amd64_jump_membase (code, AMD64_RSP, rax_offset - 0x8);
	}

	g_assert ((code - buf) <= 538);

	mono_arch_flush_icache (buf, code - buf);

	*code_size = code - buf;

	if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT) {
		guint32 code_len;

		/* Initialize the nullified class init trampoline used in the AOT case */
		nullified_class_init_trampoline = mono_arch_get_nullified_class_init_trampoline (&code_len);
	}

	*out_unwind_ops = unwind_ops;
	
	return buf;
}

gpointer
mono_arch_get_nullified_class_init_trampoline (guint32 *code_len)
{
	guint8 *code, *buf;

	code = buf = mono_global_codeman_reserve (16);
	amd64_ret (code);

	mono_arch_flush_icache (buf, code - buf);

	*code_len = code - buf;

	return buf;
}

gpointer
mono_arch_create_specific_trampoline (gpointer arg1, MonoTrampolineType tramp_type, MonoDomain *domain, guint32 *code_len)
{
	guint8 *code, *buf, *tramp;
	int size;

	tramp = mono_get_trampoline_code (tramp_type);

	if ((((guint64)arg1) >> 32) == 0)
		size = 5 + 1 + 4;
	else
		size = 5 + 1 + 8;

	code = buf = mono_domain_code_reserve_align (domain, size, 1);

	amd64_call_code (code, tramp);
	/* The trampoline code will obtain the argument from the instruction stream */
	if ((((guint64)arg1) >> 32) == 0) {
		*code = 0x4;
		*(guint32*)(code + 1) = (gint64)arg1;
		code += 5;
	} else {
		*code = 0x8;
		*(guint64*)(code + 1) = (gint64)arg1;
		code += 9;
	}

	g_assert ((code - buf) <= size);

	if (code_len)
		*code_len = size;

	mono_arch_flush_icache (buf, size);

	return buf;
}	

gpointer
mono_arch_create_rgctx_lazy_fetch_trampoline (guint32 slot)
{
	guint32 code_size;
	MonoJumpInfo *ji;

	return mono_arch_create_rgctx_lazy_fetch_trampoline_full (slot, &code_size, &ji, FALSE);
}

gpointer
mono_arch_create_rgctx_lazy_fetch_trampoline_full (guint32 slot, guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
{
	guint8 *tramp;
	guint8 *code, *buf;
	guint8 **rgctx_null_jumps;
	int tramp_size;
	int depth, index;
	int i;
	gboolean mrgctx;

	*ji = NULL;

	mrgctx = MONO_RGCTX_SLOT_IS_MRGCTX (slot);
	index = MONO_RGCTX_SLOT_INDEX (slot);
	if (mrgctx)
		index += sizeof (MonoMethodRuntimeGenericContext) / sizeof (gpointer);
	for (depth = 0; ; ++depth) {
		int size = mono_class_rgctx_get_array_size (depth, mrgctx);

		if (index < size - 1)
			break;
		index -= size - 1;
	}

	tramp_size = 64 + 8 * depth;

	code = buf = mono_global_codeman_reserve (tramp_size);

	rgctx_null_jumps = g_malloc (sizeof (guint8*) * (depth + 2));

	if (mrgctx) {
		/* get mrgctx ptr */
		amd64_mov_reg_reg (code, AMD64_RAX, AMD64_ARG_REG1, 8);
	} else {
		/* load rgctx ptr from vtable */
		amd64_mov_reg_membase (code, AMD64_RAX, AMD64_ARG_REG1, G_STRUCT_OFFSET (MonoVTable, runtime_generic_context), 8);
		/* is the rgctx ptr null? */
		amd64_test_reg_reg (code, AMD64_RAX, AMD64_RAX);
		/* if yes, jump to actual trampoline */
		rgctx_null_jumps [0] = code;
		amd64_branch8 (code, X86_CC_Z, -1, 1);
	}

	for (i = 0; i < depth; ++i) {
		/* load ptr to next array */
		if (mrgctx && i == 0)
			amd64_mov_reg_membase (code, AMD64_RAX, AMD64_RAX, sizeof (MonoMethodRuntimeGenericContext), 8);
		else
			amd64_mov_reg_membase (code, AMD64_RAX, AMD64_RAX, 0, 8);
		/* is the ptr null? */
		amd64_test_reg_reg (code, AMD64_RAX, AMD64_RAX);
		/* if yes, jump to actual trampoline */
		rgctx_null_jumps [i + 1] = code;
		amd64_branch8 (code, X86_CC_Z, -1, 1);
	}

	/* fetch slot */
	amd64_mov_reg_membase (code, AMD64_RAX, AMD64_RAX, sizeof (gpointer) * (index + 1), 8);
	/* is the slot null? */
	amd64_test_reg_reg (code, AMD64_RAX, AMD64_RAX);
	/* if yes, jump to actual trampoline */
	rgctx_null_jumps [depth + 1] = code;
	amd64_branch8 (code, X86_CC_Z, -1, 1);
	/* otherwise return */
	amd64_ret (code);

	for (i = mrgctx ? 1 : 0; i <= depth + 1; ++i)
		x86_patch (rgctx_null_jumps [i], code);

	g_free (rgctx_null_jumps);

	/* move the rgctx pointer to the VTABLE register */
	amd64_mov_reg_reg (code, MONO_ARCH_VTABLE_REG, AMD64_ARG_REG1, 8);

	if (aot) {
		*ji = mono_patch_info_list_prepend (*ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, g_strdup_printf ("specific_trampoline_lazy_fetch_%u", slot));
		amd64_mov_reg_membase (code, AMD64_R11, AMD64_RIP, 0, 8);
		amd64_jump_reg (code, AMD64_R11);
	} else {
		tramp = mono_arch_create_specific_trampoline (GUINT_TO_POINTER (slot), MONO_TRAMPOLINE_RGCTX_LAZY_FETCH, mono_get_root_domain (), NULL);

		/* jump to the actual trampoline */
		amd64_jump_code (code, tramp);
	}

	mono_arch_flush_icache (buf, code - buf);

	g_assert (code - buf <= tramp_size);

	*code_size = code - buf;

	return buf;
}

gpointer
mono_arch_create_generic_class_init_trampoline (void)
{
	guint32 code_size;
	MonoJumpInfo *ji;

	return mono_arch_create_generic_class_init_trampoline_full (&code_size, &ji, FALSE);
}

gpointer
mono_arch_create_generic_class_init_trampoline_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
{
	guint8 *tramp;
	guint8 *code, *buf;
	static int byte_offset = -1;
	static guint8 bitmask;
	guint8 *jump;
	int tramp_size;

	*ji = NULL;

	tramp_size = 64;

	code = buf = mono_global_codeman_reserve (tramp_size);

	if (byte_offset < 0)
		mono_marshal_find_bitfield_offset (MonoVTable, initialized, &byte_offset, &bitmask);

	amd64_test_membase_imm_size (code, MONO_AMD64_ARG_REG1, byte_offset, bitmask, 1);
	jump = code;
	amd64_branch8 (code, X86_CC_Z, -1, 1);

	amd64_ret (code);

	x86_patch (jump, code);

	if (aot) {
		*ji = mono_patch_info_list_prepend (*ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, "specific_trampoline_generic_class_init");
		amd64_mov_reg_membase (code, AMD64_R11, AMD64_RIP, 0, 8);
		amd64_jump_reg (code, AMD64_R11);
	} else {
		tramp = mono_arch_create_specific_trampoline (NULL, MONO_TRAMPOLINE_GENERIC_CLASS_INIT, mono_get_root_domain (), NULL);

		/* jump to the actual trampoline */
		amd64_jump_code (code, tramp);
	}

	mono_arch_flush_icache (buf, code - buf);

	g_assert (code - buf <= tramp_size);

	*code_size = code - buf;

	return buf;
}

#ifdef MONO_ARCH_MONITOR_OBJECT_REG

gpointer
mono_arch_create_monitor_enter_trampoline (void)
{
	guint32 code_size;
	MonoJumpInfo *ji;

	return mono_arch_create_monitor_enter_trampoline_full (&code_size, &ji, FALSE);
}

gpointer
mono_arch_create_monitor_enter_trampoline_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
{

	guint8 *tramp;
	guint8 *code, *buf;
	guint8 *jump_obj_null, *jump_sync_null, *jump_cmpxchg_failed, *jump_other_owner, *jump_tid;
	int tramp_size;
	int owner_offset, nest_offset, dummy;

	*ji = NULL;

	g_assert (MONO_ARCH_MONITOR_OBJECT_REG == AMD64_RDI);

	mono_monitor_threads_sync_members_offset (&owner_offset, &nest_offset, &dummy);
	g_assert (MONO_THREADS_SYNC_MEMBER_SIZE (owner_offset) == sizeof (gpointer));
	g_assert (MONO_THREADS_SYNC_MEMBER_SIZE (nest_offset) == sizeof (guint32));
	owner_offset = MONO_THREADS_SYNC_MEMBER_OFFSET (owner_offset);
	nest_offset = MONO_THREADS_SYNC_MEMBER_OFFSET (nest_offset);

	tramp_size = 96;

	code = buf = mono_global_codeman_reserve (tramp_size);

	if (mono_thread_get_tls_offset () != -1) {
		/* MonoObject* obj is in RDI */
		/* is obj null? */
		amd64_test_reg_reg (code, AMD64_RDI, AMD64_RDI);
		/* if yes, jump to actual trampoline */
		jump_obj_null = code;
		amd64_branch8 (code, X86_CC_Z, -1, 1);

		/* load obj->synchronization to RCX */
		amd64_mov_reg_membase (code, AMD64_RCX, AMD64_RDI, G_STRUCT_OFFSET (MonoObject, synchronisation), 8);
		/* is synchronization null? */
		amd64_test_reg_reg (code, AMD64_RCX, AMD64_RCX);
		/* if yes, jump to actual trampoline */
		jump_sync_null = code;
		amd64_branch8 (code, X86_CC_Z, -1, 1);

		/* load MonoThread* into RDX */
		code = mono_amd64_emit_tls_get (code, AMD64_RDX, mono_thread_get_tls_offset ());
		/* load TID into RDX */
		amd64_mov_reg_membase (code, AMD64_RDX, AMD64_RDX, G_STRUCT_OFFSET (MonoThread, tid), 8);

		/* is synchronization->owner null? */
		amd64_alu_membase_imm_size (code, X86_CMP, AMD64_RCX, owner_offset, 0, 8);
		/* if not, jump to next case */
		jump_tid = code;
		amd64_branch8 (code, X86_CC_NZ, -1, 1);

		/* if yes, try a compare-exchange with the TID */
		/* zero RAX */
		amd64_alu_reg_reg (code, X86_XOR, AMD64_RAX, AMD64_RAX);
		/* compare and exchange */
		amd64_prefix (code, X86_LOCK_PREFIX);
		amd64_cmpxchg_membase_reg_size (code, AMD64_RCX, owner_offset, AMD64_RDX, 8);
		/* if not successful, jump to actual trampoline */
		jump_cmpxchg_failed = code;
		amd64_branch8 (code, X86_CC_NZ, -1, 1);
		/* if successful, return */
		amd64_ret (code);

		/* next case: synchronization->owner is not null */
		x86_patch (jump_tid, code);
		/* is synchronization->owner == TID? */
		amd64_alu_membase_reg_size (code, X86_CMP, AMD64_RCX, owner_offset, AMD64_RDX, 8);
		/* if not, jump to actual trampoline */
		jump_other_owner = code;
		amd64_branch8 (code, X86_CC_NZ, -1, 1);
		/* if yes, increment nest */
		amd64_inc_membase_size (code, AMD64_RCX, nest_offset, 4);
		/* return */
		amd64_ret (code);

		x86_patch (jump_obj_null, code);
		x86_patch (jump_sync_null, code);
		x86_patch (jump_cmpxchg_failed, code);
		x86_patch (jump_other_owner, code);
	}

	/* jump to the actual trampoline */
#if MONO_AMD64_ARG_REG1 != AMD64_RDI
	amd64_mov_reg_reg (code, MONO_AMD64_ARG_REG1, AMD64_RDI);
#endif

	if (aot) {
		*ji = mono_patch_info_list_prepend (*ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, "specific_trampoline_monitor_enter");
		amd64_mov_reg_membase (code, AMD64_R11, AMD64_RIP, 0, 8);
		amd64_jump_reg (code, AMD64_R11);
	} else {
		tramp = mono_arch_create_specific_trampoline (NULL, MONO_TRAMPOLINE_MONITOR_ENTER, mono_get_root_domain (), NULL);

		/* jump to the actual trampoline */
		amd64_jump_code (code, tramp);
	}

	mono_arch_flush_icache (code, code - buf);
	g_assert (code - buf <= tramp_size);

	*code_size = code - buf;

	return buf;
}

gpointer
mono_arch_create_monitor_exit_trampoline (void)
{
	guint32 code_size;
	MonoJumpInfo *ji;

	return mono_arch_create_monitor_exit_trampoline_full (&code_size, &ji, FALSE);
}

gpointer
mono_arch_create_monitor_exit_trampoline_full (guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
{
	guint8 *tramp;
	guint8 *code, *buf;
	guint8 *jump_obj_null, *jump_have_waiters;
	guint8 *jump_next;
	int tramp_size;
	int owner_offset, nest_offset, entry_count_offset;

	*ji = NULL;

	g_assert (MONO_ARCH_MONITOR_OBJECT_REG == AMD64_RDI);

	mono_monitor_threads_sync_members_offset (&owner_offset, &nest_offset, &entry_count_offset);
	g_assert (MONO_THREADS_SYNC_MEMBER_SIZE (owner_offset) == sizeof (gpointer));
	g_assert (MONO_THREADS_SYNC_MEMBER_SIZE (nest_offset) == sizeof (guint32));
	g_assert (MONO_THREADS_SYNC_MEMBER_SIZE (entry_count_offset) == sizeof (gint32));
	owner_offset = MONO_THREADS_SYNC_MEMBER_OFFSET (owner_offset);
	nest_offset = MONO_THREADS_SYNC_MEMBER_OFFSET (nest_offset);
	entry_count_offset = MONO_THREADS_SYNC_MEMBER_OFFSET (entry_count_offset);

	tramp_size = 94;

	code = buf = mono_global_codeman_reserve (tramp_size);

	if (mono_thread_get_tls_offset () != -1) {
		/* MonoObject* obj is in RDI */
		/* is obj null? */
		amd64_test_reg_reg (code, AMD64_RDI, AMD64_RDI);
		/* if yes, jump to actual trampoline */
		jump_obj_null = code;
		amd64_branch8 (code, X86_CC_Z, -1, 1);

		/* load obj->synchronization to RCX */
		amd64_mov_reg_membase (code, AMD64_RCX, AMD64_RDI, G_STRUCT_OFFSET (MonoObject, synchronisation), 8);
		/* is synchronization null? */
		amd64_test_reg_reg (code, AMD64_RCX, AMD64_RCX);
		/* if not, jump to next case */
		jump_next = code;
		amd64_branch8 (code, X86_CC_NZ, -1, 1);
		/* if yes, just return */
		amd64_ret (code);

		/* next case: synchronization is not null */
		x86_patch (jump_next, code);
		/* load MonoThread* into RDX */
		code = mono_amd64_emit_tls_get (code, AMD64_RDX, mono_thread_get_tls_offset ());
		/* load TID into RDX */
		amd64_mov_reg_membase (code, AMD64_RDX, AMD64_RDX, G_STRUCT_OFFSET (MonoThread, tid), 8);
		/* is synchronization->owner == TID */
		amd64_alu_membase_reg_size (code, X86_CMP, AMD64_RCX, owner_offset, AMD64_RDX, 8);
		/* if yes, jump to next case */
		jump_next = code;
		amd64_branch8 (code, X86_CC_Z, -1, 1);
		/* if not, just return */
		amd64_ret (code);

		/* next case: synchronization->owner == TID */
		x86_patch (jump_next, code);
		/* is synchronization->nest == 1 */
		amd64_alu_membase_imm_size (code, X86_CMP, AMD64_RCX, nest_offset, 1, 4);
		/* if not, jump to next case */
		jump_next = code;
		amd64_branch8 (code, X86_CC_NZ, -1, 1);
		/* if yes, is synchronization->entry_count zero? */
		amd64_alu_membase_imm_size (code, X86_CMP, AMD64_RCX, entry_count_offset, 0, 4);
		/* if not, jump to actual trampoline */
		jump_have_waiters = code;
		amd64_branch8 (code, X86_CC_NZ, -1 , 1);
		/* if yes, set synchronization->owner to null and return */
		amd64_mov_membase_imm (code, AMD64_RCX, owner_offset, 0, 8);
		amd64_ret (code);

		/* next case: synchronization->nest is not 1 */
		x86_patch (jump_next, code);
		/* decrease synchronization->nest and return */
		amd64_dec_membase_size (code, AMD64_RCX, nest_offset, 4);
		amd64_ret (code);

		x86_patch (jump_obj_null, code);
		x86_patch (jump_have_waiters, code);
	}

	/* jump to the actual trampoline */
#if MONO_AMD64_ARG_REG1 != AMD64_RDI
	amd64_mov_reg_reg (code, MONO_AMD64_ARG_REG1, AMD64_RDI);
#endif

	if (aot) {
		*ji = mono_patch_info_list_prepend (*ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, "specific_trampoline_monitor_exit");
		amd64_mov_reg_membase (code, AMD64_R11, AMD64_RIP, 0, 8);
		amd64_jump_reg (code, AMD64_R11);
	} else {
		tramp = mono_arch_create_specific_trampoline (NULL, MONO_TRAMPOLINE_MONITOR_EXIT, mono_get_root_domain (), NULL);
		amd64_jump_code (code, tramp);
	}

	mono_arch_flush_icache (code, code - buf);
	g_assert (code - buf <= tramp_size);

	*code_size = code - buf;

	return buf;
}
#endif

void
mono_arch_invalidate_method (MonoJitInfo *ji, void *func, gpointer func_arg)
{
	/* FIXME: This is not thread safe */
	guint8 *code = ji->code_start;

	amd64_mov_reg_imm (code, AMD64_ARG_REG1, func_arg);
	amd64_mov_reg_imm (code, AMD64_R11, func);

	x86_push_imm (code, (guint64)func_arg);
	amd64_call_reg (code, AMD64_R11);
}