[Tarantool-patches] [PATCH] luajit: adde flag of partial comp. with Lua 5.2
Olga Arkhangelskaia
arkholga at tarantool.org
Tue Nov 19 12:31:11 MSK 2019
Although we do not turn on full compatibility with Lua 5.2 we do need some of
its features (eg. __pairs/__ipairs).This functionality brakes existing code.
However, if the necessity is very high or is strongly demanded we should
have possibility to use it. We introduce LUAJIT_ENABLE_LUA52COMPAT_PART
flag.
Some of the Lua 5.2's features that are likely to break existing code can be
turned on under this flag. At the moment it is pirs/ipairs metmethod.
---
src/Makefile | 4 ++++
src/lib_base.c | 4 ++--
src/lj_arch.h | 6 ++++++
src/lj_obj.h | 2 +-
src/vm_x86.dasc | 4 ++--
5 files changed, 15 insertions(+), 5 deletions(-)
diff --git a/src/Makefile b/src/Makefile
index 827d4a4..e8fd91a 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -101,6 +101,10 @@ XCFLAGS=
# Note: this does not provide full compatibility with Lua 5.2 at this time.
#XCFLAGS+= -DLUAJIT_ENABLE_LUA52COMPAT
#
+#Features from Lua 5.2 that was demanded more than once or are essential for
+#for the project. At the moment only pairs/ipairs can be enabled via this flag.
+#XCFLAGS+= -DLUAJIT_ENABLE_LUA52COMPAT_PART
+#
# Disable the JIT compiler, i.e. turn LuaJIT into a pure interpreter.
#XCFLAGS+= -DLUAJIT_DISABLE_JIT
#
diff --git a/src/lib_base.c b/src/lib_base.c
index 3a75787..6cc0fcc 100644
--- a/src/lib_base.c
+++ b/src/lib_base.c
@@ -81,12 +81,12 @@ LJLIB_ASM(next)
return FFH_UNREACHABLE;
}
-#if LJ_52 || LJ_HASFFI
+#if LJ_52_PART || LJ_HASFFI
static int ffh_pairs(lua_State *L, MMS mm)
{
TValue *o = lj_lib_checkany(L, 1);
cTValue *mo = lj_meta_lookup(L, o, mm);
- if ((LJ_52 || tviscdata(o)) && !tvisnil(mo)) {
+ if ((LJ_52_PART || tviscdata(o)) && !tvisnil(mo)) {
L->top = o+1; /* Only keep one argument. */
copyTV(L, L->base-1-LJ_FR2, mo); /* Replace callable. */
return FFH_TAILCALL;
diff --git a/src/lj_arch.h b/src/lj_arch.h
index c8d7138..39d70d5 100644
--- a/src/lj_arch.h
+++ b/src/lj_arch.h
@@ -564,4 +564,10 @@
#define LJ_52 0
#endif
+/* Partial compatibility with Lua 5.2 */
+#if defined(LUAJIT_ENABLE_LUA52COMPAT_PART) || defined (LUAJIT_ENABLE_LUA52COMPAT)
+#define LJ_52_PART 1
+#else
+#define LJ_52_PART 0
+#endif
#endif
diff --git a/src/lj_obj.h b/src/lj_obj.h
index f368578..3788cee 100644
--- a/src/lj_obj.h
+++ b/src/lj_obj.h
@@ -530,7 +530,7 @@ enum {
#define MMDEF_FFI(_)
#endif
-#if LJ_52 || LJ_HASFFI
+#if LJ_52 || LJ_HASFFI || LJ_52_PART
#define MMDEF_PAIRS(_) _(pairs) _(ipairs)
#else
#define MMDEF_PAIRS(_)
diff --git a/src/vm_x86.dasc b/src/vm_x86.dasc
index 56bee14..ad6216e 100644
--- a/src/vm_x86.dasc
+++ b/src/vm_x86.dasc
@@ -1724,7 +1724,7 @@ static void build_subroutines(BuildCtx *ctx)
|.ffunc_1 pairs
| mov TAB:RB, [BASE]
| cmp dword [BASE+4], LJ_TTAB; jne ->fff_fallback
-#if LJ_52
+#if LJ_52_PART
| cmp dword TAB:RB->metatable, 0; jne ->fff_fallback
#endif
| mov CFUNC:RB, [BASE-8]
@@ -1791,7 +1791,7 @@ static void build_subroutines(BuildCtx *ctx)
|.ffunc_1 ipairs
| mov TAB:RB, [BASE]
| cmp dword [BASE+4], LJ_TTAB; jne ->fff_fallback
-#if LJ_52
+#if LJ_52_PART
| cmp dword TAB:RB->metatable, 0; jne ->fff_fallback
#endif
| mov CFUNC:RB, [BASE-8]
--
2.20.1 (Apple Git-117)
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