Implement x86 support for monitor enter/exit fastpaths under sgen

diff --git a/mono/mini/method-to-ir.c b/mono/mini/method-to-ir.c
index 1df903e470f01d29d96491cf939a989c759c57b8..90cad3c3e52d77cfb412713052bfaff1353d1256 100644 (file)
--- a/mono/mini/method-to-ir.c
+++ b/mono/mini/method-to-ir.c
@@ -4324,8 +4324,11 @@ mini_emit_inst_for_method (MonoCompile *cfg, MonoMethod *cmethod, MonoMethodSign
                }
        } else if (cmethod->klass == mono_defaults.monitor_class) {
 #if defined(MONO_ARCH_MONITOR_OBJECT_REG)
-               /* The trampolines don't work under SGEN */
-               gboolean is_moving_gc = mono_gc_is_moving ();
+               gboolean is_moving_gc = FALSE;
+               /* The trampolines only work under X86 for SGEN */
+#if !defined(TARGET_X86)
+               is_moving_gc = mono_gc_is_moving ();
+#endif
 
                if (strcmp (cmethod->name, "Enter") == 0 && fsig->param_count == 1 && !is_moving_gc) {
                        MonoCallInst *call;

diff --git a/mono/mini/tramp-x86.c b/mono/mini/tramp-x86.c
index 853ae68f094212c22a9c20464dea8d44f6dd7f4a..5b9e51507a966bdf47278ea31f41e5b134d30775 100644 (file)
--- a/mono/mini/tramp-x86.c
+++ b/mono/mini/tramp-x86.c
@@ -17,6 +17,7 @@
 #include <mono/metadata/mono-debug.h>
 #include <mono/metadata/mono-debug-debugger.h>
 #include <mono/metadata/monitor.h>
+#include <mono/metadata/gc-internal.h>
 #include <mono/arch/x86/x86-codegen.h>
 
 #include <mono/utils/memcheck.h>
@@ -733,7 +734,7 @@ mono_arch_create_monitor_enter_trampoline (MonoTrampInfo **info, gboolean aot)
 {
        guint8 *tramp = mono_get_trampoline_code (MONO_TRAMPOLINE_MONITOR_ENTER);
        guint8 *code, *buf;
-       guint8 *jump_obj_null, *jump_sync_null, *jump_other_owner, *jump_cmpxchg_failed, *jump_tid;
+       guint8 *jump_obj_null, *jump_sync_null, *jump_other_owner, *jump_cmpxchg_failed, *jump_tid, *jump_sync_thin_hash = NULL;
        int tramp_size;
        int owner_offset, nest_offset, dummy;
        MonoJumpInfo *ji = NULL;
@@ -761,8 +762,21 @@ mono_arch_create_monitor_enter_trampoline (MonoTrampInfo **info, gboolean aot)
 
                /* load obj->synchronization to ECX */
                x86_mov_reg_membase (code, X86_ECX, X86_EAX, G_STRUCT_OFFSET (MonoObject, synchronisation), 4);
+
+               if (mono_gc_is_moving ()) {
+                       /*if bit zero is set it's a thin hash*/
+                       /*FIXME use testb encoding*/
+                       x86_test_reg_imm (code, X86_ECX, 0x01);
+                       jump_sync_thin_hash = code;
+                       x86_branch8 (code, X86_CC_NE, -1, 1);
+
+                       /*clear bits used by the gc*/
+                       x86_alu_reg_imm (code, X86_AND, X86_ECX, ~0x3);
+               }
+
                /* is synchronization null? */
                x86_test_reg_reg (code, X86_ECX, X86_ECX);
+
                /* if yes, jump to actual trampoline */
                jump_sync_null = code;
                x86_branch8 (code, X86_CC_Z, -1, 1);
@@ -807,6 +821,8 @@ mono_arch_create_monitor_enter_trampoline (MonoTrampInfo **info, gboolean aot)
 
                /* push obj */
                x86_patch (jump_obj_null, code);
+               if (jump_sync_thin_hash)
+                       x86_patch (jump_sync_thin_hash, code);
                x86_patch (jump_sync_null, code);
                x86_patch (jump_other_owner, code);
                x86_push_reg (code, X86_EAX);
@@ -846,7 +862,7 @@ mono_arch_create_monitor_exit_trampoline (MonoTrampInfo **info, gboolean aot)
 {
        guint8 *tramp = mono_get_trampoline_code (MONO_TRAMPOLINE_MONITOR_EXIT);
        guint8 *code, *buf;
-       guint8 *jump_obj_null, *jump_have_waiters, *jump_sync_null, *jump_not_owned;
+       guint8 *jump_obj_null, *jump_have_waiters, *jump_sync_null, *jump_not_owned, *jump_sync_thin_hash = NULL;
        guint8 *jump_next;
        int tramp_size;
        int owner_offset, nest_offset, entry_count_offset;
@@ -863,7 +879,7 @@ mono_arch_create_monitor_exit_trampoline (MonoTrampInfo **info, gboolean aot)
        nest_offset = MONO_THREADS_SYNC_MEMBER_OFFSET (nest_offset);
        entry_count_offset = MONO_THREADS_SYNC_MEMBER_OFFSET (entry_count_offset);
 
-       tramp_size = NACL_SIZE (64, 128);
+       tramp_size = NACL_SIZE (96, 128);
 
        code = buf = mono_global_codeman_reserve (tramp_size);
 
@@ -877,6 +893,18 @@ mono_arch_create_monitor_exit_trampoline (MonoTrampInfo **info, gboolean aot)
 
                /* load obj->synchronization to ECX */
                x86_mov_reg_membase (code, X86_ECX, X86_EAX, G_STRUCT_OFFSET (MonoObject, synchronisation), 4);
+
+               if (mono_gc_is_moving ()) {
+                       /*if bit zero is set it's a thin hash*/
+                       /*FIXME use testb encoding*/
+                       x86_test_reg_imm (code, X86_ECX, 0x01);
+                       jump_sync_thin_hash = code;
+                       x86_branch8 (code, X86_CC_NE, -1, 1);
+
+                       /*clear bits used by the gc*/
+                       x86_alu_reg_imm (code, X86_AND, X86_ECX, ~0x3);
+               }
+
                /* is synchronization null? */
                x86_test_reg_reg (code, X86_ECX, X86_ECX);
                /* if yes, jump to actual trampoline */
@@ -917,6 +945,8 @@ mono_arch_create_monitor_exit_trampoline (MonoTrampInfo **info, gboolean aot)
 
                /* push obj and jump to the actual trampoline */
                x86_patch (jump_obj_null, code);
+               if (jump_sync_thin_hash)
+                       x86_patch (jump_sync_thin_hash, code);
                x86_patch (jump_have_waiters, code);
                x86_patch (jump_not_owned, code);
                x86_patch (jump_sync_null, code);