[Tarantool-patches] [PATCH luajit] GC64: enable sysprof support

[Maxim Kokryashkin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

This patch reverts changes introduced via commit
71e7020637bb15024ceb7e93ce66b61870567339 ('GC64: disable
sysprof support'), fixing the incorrect behavior in vm
by adding the `LJ_HASSYSPROF` flag to the DynASM flags.

Resolves tarantool/tarantool#7919
Related to tarantool/tarantool#781
---
Issue: https://github.com/tarantool/tarantool/issues/7919
Branch: https://github.com/tarantool/luajit/tree/fckxorg/gh-7919-sysprof-gc64
PR: https://github.com/tarantool/tarantool/pull/7922

 cmake/SetDynASMFlags.cmake                    |  5 +++
 src/lj_arch.h                                 |  2 +-
 src/lj_obj.h                                  |  2 +
 src/vm_x64.dasc                               | 42 ++++++++++++++-----
 src/vm_x86.dasc                               |  8 ++++
 .../misclib-sysprof-capi.test.lua             |  7 ++--
 .../misclib-sysprof-lapi.test.lua             |  5 +--
 7 files changed, 52 insertions(+), 19 deletions(-)

diff --git a/cmake/SetDynASMFlags.cmake b/cmake/SetDynASMFlags.cmake
index 8e10758f..142d7e64 100644
--- a/cmake/SetDynASMFlags.cmake
+++ b/cmake/SetDynASMFlags.cmake
@@ -113,6 +113,11 @@ if(NOT FOUND EQUAL -1)
   AppendFlags(HOST_C_FLAGS -DLUAJIT_NO_UNWIND)
 endif()
 
+string(FIND "${TESTARCH}" "LJ_HASSYSPROF 1" FOUND)
+if(NOT FOUND EQUAL -1)
+  list(APPEND DYNASM_FLAGS -D LJ_HASSYSPROF)
+endif()
+
 string(REGEX MATCH "LJ_ARCH_VERSION ([0-9]+)" LUAJIT_ARCH_VERSION ${TESTARCH})
 list(APPEND DYNASM_FLAGS -D VER=${CMAKE_MATCH_1})
 
diff --git a/src/lj_arch.h b/src/lj_arch.h
index 40129d9e..cd02fee1 100644
--- a/src/lj_arch.h
+++ b/src/lj_arch.h
@@ -595,7 +595,7 @@
 #endif
 
 /* Disable or enable the platform and Lua profiler. */
-#if defined(LUAJIT_DISABLE_SYSPROF) || defined(LJ_ARCH_NOSYSPROF) || !LJ_TARGET_LINUX || LJ_GC64
+#if defined(LUAJIT_DISABLE_SYSPROF) || defined(LJ_ARCH_NOSYSPROF) || !LJ_TARGET_LINUX
 #define LJ_HASSYSPROF		0
 #else
 #define LJ_HASSYSPROF		1
diff --git a/src/lj_obj.h b/src/lj_obj.h
index d1451c3a..45507e0d 100644
--- a/src/lj_obj.h
+++ b/src/lj_obj.h
@@ -674,7 +674,9 @@ typedef struct global_State {
   MRef jit_base;	/* Current JIT code L->base or NULL. */
   MRef ctype_state;	/* Pointer to C type state. */
   GCRef gcroot[GCROOT_MAX];  /* GC roots. */
+#ifdef LJ_HASSYSPROF
   TValue *top_frame;	/* Top frame for sysprof. */
+#endif
 } global_State;
 
 #define mainthread(g)	(&gcref(g->mainthref)->th)
diff --git a/src/vm_x64.dasc b/src/vm_x64.dasc
index 974047d3..59f117ba 100644
--- a/src/vm_x64.dasc
+++ b/src/vm_x64.dasc
@@ -345,6 +345,22 @@
 |  mov dword [DISPATCH+DISPATCH_GL(vmstate)], ~LJ_VMST_..st
 |.endmacro
 |
+|// Stash interpreter's internal base and set current VM state.
+|// XXX: Each time profiler sees LFUNC, CFUNC or FFUNC state, it tries
+|// to dump Lua calling stack, so it needs a stack base pointer.
+|// If the sampling signal arriving during the execution of the VM code,
+|// base pointer stored in the current lua_State can be irrelevant, as
+|// it syncs with the BASE register only when the control is passed to
+|// user code. So we need to sync the BASE on each vmstate change to
+|// keep it consistent.
+|.macro set_vmstate_sync_base, st
+|.if LJ_HASSYSPROF
+|  set_vmstate INTERP  // Guard for non-atomic VM context restoration
+|  mov qword [DISPATCH+DISPATCH_GL(top_frame)], BASE
+|.endif
+|  set_vmstate st
+|.endmacro
+|
 |// Uses TMPRd (r10d).
 |.macro save_vmstate
 |.if not WIN
@@ -356,6 +372,12 @@
 |// Uses r10d.
 |.macro restore_vmstate
 |.if not WIN
+|.if LJ_HASSYSPROF
+|  set_vmstate INTERP
+|  mov TMPR, SAVE_L
+|  mov TMPR, L:TMPR->base
+|  mov qword [DISPATCH+DISPATCH_GL(top_frame)], TMPR
+|.endif
 |  mov TMPRd, SAVE_VMSTATE
 |  mov dword [DISPATCH+DISPATCH_GL(vmstate)], TMPRd
 |.endif // WIN
@@ -435,7 +457,7 @@ static void build_subroutines(BuildCtx *ctx)
   |  jnz ->vm_returnp
   |
   |  // Return to C.
-  |  set_vmstate CFUNC
+  |  set_vmstate_sync_base CFUNC
   |  and PC, -8
   |  sub PC, BASE
   |  neg PC				// Previous base = BASE - delta.
@@ -725,7 +747,7 @@ static void build_subroutines(BuildCtx *ctx)
   |  cleartp LFUNC:KBASE
   |  mov KBASE, LFUNC:KBASE->pc
   |  mov KBASE, [KBASE+PC2PROTO(k)]
-  |  set_vmstate LFUNC			// LFUNC after KBASE restoration.
+  |  set_vmstate_sync_base LFUNC	// LFUNC after KBASE restoration.
   |  // BASE = base, RC = result, RB = meta base
   |  jmp RA				// Jump to continuation.
   |
@@ -1166,7 +1188,7 @@ static void build_subroutines(BuildCtx *ctx)
   |
   |.macro .ffunc, name
   |->ff_ .. name:
-  |  set_vmstate FFUNC
+  |  set_vmstate_sync_base FFUNC
   |.endmacro
   |
   |.macro .ffunc_1, name
@@ -1748,7 +1770,7 @@ static void build_subroutines(BuildCtx *ctx)
   |  movzx RAd, PC_RA
   |  neg RA
   |  lea BASE, [BASE+RA*8-16]		// base = base - (RA+2)*8
-  |  set_vmstate LFUNC			// LFUNC state after BASE restoration.
+  |  set_vmstate_sync_base LFUNC	// LFUNC state after BASE restoration.
   |  ins_next
   |
   |6:  // Fill up results with nil.
@@ -2513,7 +2535,7 @@ static void build_subroutines(BuildCtx *ctx)
   |  mov KBASE, [KBASE+PC2PROTO(k)]
   |  mov L:RB->base, BASE
   |  mov qword [DISPATCH+DISPATCH_GL(jit_base)], 0
-  |  set_vmstate LFUNC			// LFUNC after BASE & KBASE restoration.
+  |  set_vmstate_sync_base LFUNC	// LFUNC after BASE & KBASE restoration.
   |  // Modified copy of ins_next which handles function header dispatch, too.
   |  mov RCd, [PC]
   |  movzx RAd, RCH
@@ -2730,7 +2752,7 @@ static void build_subroutines(BuildCtx *ctx)
   |  call extern lj_ccallback_enter	// (CTState *cts, void *cf)
   |  // lua_State * returned in eax (RD).
   |  mov BASE, L:RD->base
-  |  set_vmstate LFUNC			// LFUNC after BASE restoration.
+  |  set_vmstate_sync_base LFUNC	// LFUNC after BASE restoration.
   |  mov RD, L:RD->top
   |  sub RD, BASE
   |  mov LFUNC:RB, [BASE-16]
@@ -4299,7 +4321,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defop)
     |  mov KBASE, LFUNC:KBASE->pc
     |  mov KBASE, [KBASE+PC2PROTO(k)]
     |  // LFUNC after the old BASE & KBASE is restored.
-    |  set_vmstate LFUNC
+    |  set_vmstate_sync_base LFUNC
     |  ins_next
     |
     |6:  // Fill up results with nil.
@@ -4591,7 +4613,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defop)
     |  ins_AD  // BASE = new base, RA = framesize, RD = nargs+1
     |  mov KBASE, [PC-4+PC2PROTO(k)]
     |  mov L:RB, SAVE_L
-    |  set_vmstate LFUNC		// LFUNC after KBASE restoration.
+    |  set_vmstate_sync_base LFUNC	// LFUNC after KBASE restoration.
     |  lea RA, [BASE+RA*8]		// Top of frame.
     |  cmp RA, L:RB->maxstack
     |  ja ->vm_growstack_f
@@ -4629,7 +4651,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defop)
     |  mov [RD-8], RB			// Store delta + FRAME_VARG.
     |  mov [RD-16], LFUNC:KBASE		// Store copy of LFUNC.
     |  mov L:RB, SAVE_L
-    |  set_vmstate LFUNC		// LFUNC after KBASE restoration.
+    |  set_vmstate_sync_base LFUNC	// LFUNC after KBASE restoration.
     |  lea RA, [RD+RA*8]
     |  cmp RA, L:RB->maxstack
     |  ja ->vm_growstack_v		// Need to grow stack.
@@ -4685,7 +4707,7 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defop)
       |  mov CARG1, L:RB		// Caveat: CARG1 may be RA.
     }
     |  ja ->vm_growstack_c		// Need to grow stack.
-    |  set_vmstate CFUNC		// CFUNC before entering C function.
+    |  set_vmstate_sync_base CFUNC	// CFUNC before entering C function.
     if (op == BC_FUNCC) {
       |  call KBASE			// (lua_State *L)
     } else {
diff --git a/src/vm_x86.dasc b/src/vm_x86.dasc
index 22f69edf..f7ffe5d2 100644
--- a/src/vm_x86.dasc
+++ b/src/vm_x86.dasc
@@ -452,8 +452,10 @@
 |// user code. So we need to sync the BASE on each vmstate change to
 |// keep it consistent.
 |.macro set_vmstate_sync_base, st
+|.if LJ_HASSYSPROF
 |  set_vmstate INTERP  // Guard for non-atomic VM context restoration
 |  mov dword [DISPATCH+DISPATCH_GL(top_frame)], BASE
+|.endif
 |  set_vmstate st
 |.endmacro
 |
@@ -475,19 +477,25 @@
 |// Uses spilled ecx on x86 or XCHGd (r11d) on x64.
 |.macro restore_vmstate
 |.if not WIN
+|.if LJ_HASSYSPROF
 |  set_vmstate INTERP
+|.endif
 |.if not X64
 |  mov SPILLECX, ecx
+|.if LJ_HASSYSPROF
 |  mov ecx, SAVE_L
 |  mov ecx, L:ecx->base
 |  mov dword [DISPATCH+DISPATCH_GL(top_frame)], ecx
+|.endif
 |  mov ecx, SAVE_VMSTATE
 |  mov dword [DISPATCH+DISPATCH_GL(vmstate)], ecx
 |  mov ecx, SPILLECX
 |.else // X64
+|.if LJ_HASSYSPROF
 |  mov XCHGd, SAVE_L
 |  mov XCHGd, L:XCHGd->base
 |  mov dword [DISPATCH+DISPATCH_GL(top_frame)], XCHGd
+|.endif
 |  mov XCHGd, SAVE_VMSTATE
 |  mov dword [DISPATCH+DISPATCH_GL(vmstate)], XCHGd
 |.endif // X64
diff --git a/test/tarantool-tests/misclib-sysprof-capi.test.lua b/test/tarantool-tests/misclib-sysprof-capi.test.lua
index afb99cf2..dad0fe4a 100644
--- a/test/tarantool-tests/misclib-sysprof-capi.test.lua
+++ b/test/tarantool-tests/misclib-sysprof-capi.test.lua
@@ -1,8 +1,7 @@
 -- Sysprof is implemented for x86 and x64 architectures only.
-local ffi = require("ffi")
-require("utils").skipcond(
-  jit.arch ~= "x86" and jit.arch ~= "x64" or jit.os ~= "Linux"
-    or ffi.abi("gc64"),
+local utils = require("utils")
+utils.skipcond(
+  jit.arch ~= "x86" and jit.arch ~= "x64" or jit.os ~= "Linux",
   jit.arch.." architecture or "..jit.os..
   " OS is NIY for sysprof"
 )
diff --git a/test/tarantool-tests/misclib-sysprof-lapi.test.lua b/test/tarantool-tests/misclib-sysprof-lapi.test.lua
index dbff41b0..4bf10e8d 100644
--- a/test/tarantool-tests/misclib-sysprof-lapi.test.lua
+++ b/test/tarantool-tests/misclib-sysprof-lapi.test.lua
@@ -1,10 +1,7 @@
 -- Sysprof is implemented for x86 and x64 architectures only.
-local ffi = require("ffi")
 local utils = require("utils")
-
 utils.skipcond(
-  jit.arch ~= "x86" and jit.arch ~= "x64" or jit.os ~= "Linux"
-    or ffi.abi("gc64"),
+  jit.arch ~= "x86" and jit.arch ~= "x64" or jit.os ~= "Linux",
   jit.arch.." architecture or "..jit.os..
   " OS is NIY for sysprof"
 )
-- 
2.38.0