cmd/compile: emit writebarriers in specified ABI

old code was always ABI0, new code tracks the default
this may cause some write barrier removals to fail to fire

Updates #40724.

Change-Id: I656bdd5511c5bd6ee6e021999e30d842a6b9f0a5
Reviewed-on: https://go-review.googlesource.com/c/go/+/305671
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

diff --git a/src/cmd/compile/internal/ssa/writebarrier.go b/src/cmd/compile/internal/ssa/writebarrier.go
index bbb5a7c148c367f63410a521900f327e996453e6..f0eceb7abe82b923872cadcab4382be095ef3eec 100644 (file)
--- a/src/cmd/compile/internal/ssa/writebarrier.go
+++ b/src/cmd/compile/internal/ssa/writebarrier.go
@@ -483,38 +483,56 @@ func (f *Func) computeZeroMap() map[ID]ZeroRegion {
 func wbcall(pos src.XPos, b *Block, fn, typ *obj.LSym, ptr, val, mem, sp, sb *Value) *Value {
        config := b.Func.Config
 
+       var wbargs []*Value
+       // TODO (register args) this is a bit of a hack.
+       inRegs := b.Func.ABIDefault == b.Func.ABI1 && len(config.intParamRegs) >= 3
+
        // put arguments on stack
        off := config.ctxt.FixedFrameSize()
 
        var argTypes []*types.Type
        if typ != nil { // for typedmemmove
                taddr := b.NewValue1A(pos, OpAddr, b.Func.Config.Types.Uintptr, typ, sb)
-               off = round(off, taddr.Type.Alignment())
-               arg := b.NewValue1I(pos, OpOffPtr, taddr.Type.PtrTo(), off, sp)
-               mem = b.NewValue3A(pos, OpStore, types.TypeMem, ptr.Type, arg, taddr, mem)
                argTypes = append(argTypes, b.Func.Config.Types.Uintptr)
-               off += taddr.Type.Size()
+               if inRegs {
+                       wbargs = append(wbargs, taddr)
+               } else {
+                       off = round(off, taddr.Type.Alignment())
+                       arg := b.NewValue1I(pos, OpOffPtr, taddr.Type.PtrTo(), off, sp)
+                       mem = b.NewValue3A(pos, OpStore, types.TypeMem, ptr.Type, arg, taddr, mem)
+                       off += taddr.Type.Size()
+               }
        }
 
-       off = round(off, ptr.Type.Alignment())
-       arg := b.NewValue1I(pos, OpOffPtr, ptr.Type.PtrTo(), off, sp)
-       mem = b.NewValue3A(pos, OpStore, types.TypeMem, ptr.Type, arg, ptr, mem)
        argTypes = append(argTypes, ptr.Type)
-       off += ptr.Type.Size()
+       if inRegs {
+               wbargs = append(wbargs, ptr)
+       } else {
+               off = round(off, ptr.Type.Alignment())
+               arg := b.NewValue1I(pos, OpOffPtr, ptr.Type.PtrTo(), off, sp)
+               mem = b.NewValue3A(pos, OpStore, types.TypeMem, ptr.Type, arg, ptr, mem)
+               off += ptr.Type.Size()
+       }
 
        if val != nil {
-               off = round(off, val.Type.Alignment())
-               arg = b.NewValue1I(pos, OpOffPtr, val.Type.PtrTo(), off, sp)
-               mem = b.NewValue3A(pos, OpStore, types.TypeMem, val.Type, arg, val, mem)
                argTypes = append(argTypes, val.Type)
-               off += val.Type.Size()
+               if inRegs {
+                       wbargs = append(wbargs, val)
+               } else {
+                       off = round(off, val.Type.Alignment())
+                       arg := b.NewValue1I(pos, OpOffPtr, val.Type.PtrTo(), off, sp)
+                       mem = b.NewValue3A(pos, OpStore, types.TypeMem, val.Type, arg, val, mem)
+                       off += val.Type.Size()
+               }
        }
        off = round(off, config.PtrSize)
+       wbargs = append(wbargs, mem)
 
        // issue call
-       mem = b.NewValue1A(pos, OpStaticCall, types.TypeResultMem, StaticAuxCall(fn, b.Func.ABIDefault.ABIAnalyzeTypes(nil, argTypes, nil)), mem)
-       mem.AuxInt = off - config.ctxt.FixedFrameSize()
-       return b.NewValue1I(pos, OpSelectN, types.TypeMem, 0, mem)
+       call := b.NewValue0A(pos, OpStaticCall, types.TypeResultMem, StaticAuxCall(fn, b.Func.ABIDefault.ABIAnalyzeTypes(nil, argTypes, nil)))
+       call.AddArgs(wbargs...)
+       call.AuxInt = off - config.ctxt.FixedFrameSize()
+       return b.NewValue1I(pos, OpSelectN, types.TypeMem, 0, call)
 }
 
 // round to a multiple of r, r is a power of 2