fix: missing write-barrier when truncate empty slice (#531)

bytedance · Sep 22, 2023 · a2d3aa9 · a2d3aa9
1 parent dd7da44
commit a2d3aa9
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Showing 3 changed files with 5 additions and 15 deletions.
diff --git a/internal/decoder/assembler_regabi_amd64.go b/internal/decoder/assembler_regabi_amd64.go
@@ -1164,7 +1164,7 @@ var (
 
 var (
     _F_FieldMap_GetCaseInsensitive obj.Addr
-    _Empty_Slice = make([]byte, 0)
+    _Empty_Slice = []byte{}
     _Zero_Base = int64(uintptr(((*rt.GoSlice)(unsafe.Pointer(&_Empty_Slice))).Ptr))
 )
 
@@ -1641,7 +1641,8 @@ func (self *_Assembler) _asm_OP_check_empty(p *_Instr) {
         self.Emit("CMPB", jit.Sib(_IP, _IC, 1, 0), jit.Imm(int64(rbracket))) // CMPB    (IP)(IC), ']'
         self.Sjmp("JNE" , "_not_empty_array_{n}")                            // JNE     _not_empty_array_{n}
         self.Emit("MOVQ", _AX, _IC)                                          // MOVQ    AX, IC
-        self.StorePtr(_Zero_Base, jit.Ptr(_VP, 0), _AX)                      // MOVQ    $zerobase, (VP)
+        self.Emit("MOVQ", jit.Imm(_Zero_Base), _AX)
+        self.WritePtrAX(9, jit.Ptr(_VP, 0), false)
         self.Emit("PXOR", _X0, _X0)                                          // PXOR    X0, X0
         self.Emit("MOVOU", _X0, jit.Ptr(_VP, 8))                             // MOVOU   X0, 8(VP)
         self.Xjmp("JMP" , p.vi())                                            // JMP     {p.vi()}

diff --git a/internal/decoder/assembler_stkabi_amd64.go b/internal/decoder/assembler_stkabi_amd64.go
@@ -1651,7 +1651,8 @@ func (self *_Assembler) _asm_OP_check_empty(p *_Instr) {
         self.Emit("CMPB", jit.Sib(_IP, _IC, 1, 0), jit.Imm(int64(rbracket))) // CMPB    (IP)(IC), ']'
         self.Sjmp("JNE" , "_not_empty_array_{n}")                            // JNE     _not_empty_array_{n}
         self.Emit("MOVQ", _AX, _IC)                                          // MOVQ    AX, IC
-        self.StorePtr(_Zero_Base, jit.Ptr(_VP, 0), _AX)                      // MOVQ    $zerobase, (VP)
+        self.Emit("MOVQ", jit.Imm(_Zero_Base), _AX)
+        self.WritePtrAX(9, jit.Ptr(_VP, 0), false)
         self.Emit("PXOR" , _X0, _X0)                                         // PXOR    X0, X0
         self.Emit("MOVOU", _X0, jit.Ptr(_VP, 8))                             // MOVOU   X0, 8(VP)
         self.Xjmp("JMP" , p.vi())                                            // JMP     {p.vi()}

diff --git a/internal/jit/assembler_amd64.go b/internal/jit/assembler_amd64.go
@@ -72,18 +72,6 @@ func (self *BaseAssembler) NOPn(n int) {
     }
 }
 
-func (self *BaseAssembler) StorePtr(ptr int64, to obj.Addr, tmp obj.Addr) {
-    if (to.Type != obj.TYPE_MEM) || (tmp.Type != obj.TYPE_REG) {
-        panic("must store imm to memory, tmp must be register")
-    }
-    if (ptr >> 32) != 0 {
-        self.Emit("MOVQ", Imm(ptr), tmp)
-        self.Emit("MOVQ", tmp, to)
-    } else {
-        self.Emit("MOVQ", Imm(ptr), to);
-    }
-}
-
 func (self *BaseAssembler) Byte(v ...byte) {
     for ; len(v) >= 8; v = v[8:] { self.From("QUAD", Imm(rt.Get64(v))) }
     for ; len(v) >= 4; v = v[4:] { self.From("LONG", Imm(int64(rt.Get32(v)))) }