From: David Chase <drchase@google.com>
Date: Wed, 17 Feb 2021 23:01:52 +0000 (-0500)
Subject: cmd/compile: pass arguments as register parameters to StaticCall.
X-Git-Tag: go1.17beta1~1298
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=95ff296a11606cec32fb697c74aee520f23498b0;p=gostls13.git

cmd/compile: pass arguments as register parameters to StaticCall.

Additional register-parameter plumbing, not all the way to the end;
if you test register parameter-passing, it fails mid-compilation.

For #40724.

Change-Id: Ibb675022c9156779a451726329890e52fca1cb33
Reviewed-on: https://go-review.googlesource.com/c/go/+/293398
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
---

diff --git a/src/cmd/compile/internal/ssa/expand_calls.go b/src/cmd/compile/internal/ssa/expand_calls.go
index 1868e3f073..ff16eac90f 100644
--- a/src/cmd/compile/internal/ssa/expand_calls.go
+++ b/src/cmd/compile/internal/ssa/expand_calls.go
@@ -806,7 +806,6 @@ func (x *expandState) storeArgOrLoad(pos src.XPos, b *Block, source, mem *Value,
 
 	s := mem
 	if storeRc.hasRegs() {
-		// TODO(register args)
 		storeRc.addArg(source)
 	} else {
 		dst := x.offsetFrom(storeRc.storeDest, offset, types.NewPtr(t))
@@ -821,21 +820,15 @@ func (x *expandState) storeArgOrLoad(pos src.XPos, b *Block, source, mem *Value,
 // rewriteArgs removes all the Args from a call and converts the call args into appropriate
 // stores (or later, register movement).  Extra args for interface and closure calls are ignored,
 // but removed.
-func (x *expandState) rewriteArgs(v *Value, firstArg int) *Value {
+func (x *expandState) rewriteArgs(v *Value, firstArg int) (*Value, []*Value) {
 	// Thread the stores on the memory arg
 	aux := v.Aux.(*AuxCall)
 	pos := v.Pos.WithNotStmt()
 	m0 := v.MemoryArg()
 	mem := m0
 	allResults := []*Value{}
-	for i, a := range v.Args {
-		if i < firstArg {
-			continue
-		}
-		if a == m0 { // mem is last.
-			break
-		}
-		auxI := int64(i - firstArg)
+	for i, a := range v.Args[firstArg : len(v.Args)-1] { // skip leading non-parameter SSA Args and trailing mem SSA Arg.
+		auxI := int64(i)
 		aRegs := aux.RegsOfArg(auxI)
 		aType := aux.TypeOfArg(auxI)
 		if a.Op == OpDereference {
@@ -863,11 +856,10 @@ func (x *expandState) rewriteArgs(v *Value, firstArg int) *Value {
 			}
 			rc.init(aRegs, aux.abiInfo, result, x.sp)
 			mem = x.storeArgOrLoad(pos, v.Block, a, mem, aType, aOffset, 0, rc)
-			// TODO append mem to Result, update type
 		}
 	}
 	v.resetArgs()
-	return mem
+	return mem, allResults
 }
 
 // expandCalls converts LE (Late Expansion) calls that act like they receive value args into a lower-level form
@@ -921,17 +913,30 @@ func expandCalls(f *Func) {
 		for _, v := range b.Values {
 			switch v.Op {
 			case OpStaticLECall:
-				mem := x.rewriteArgs(v, 0)
-				v.SetArgs1(mem)
+				mem, results := x.rewriteArgs(v, 0)
+				v.AddArgs(results...)
+				v.AddArg(mem)
 			case OpClosureLECall:
 				code := v.Args[0]
 				context := v.Args[1]
-				mem := x.rewriteArgs(v, 2)
-				v.SetArgs3(code, context, mem)
+				mem, results := x.rewriteArgs(v, 2)
+				if len(results) == 0 {
+					v.SetArgs3(code, context, mem)
+				} else {
+					v.SetArgs2(code, context)
+					v.AddArgs(results...)
+					v.AddArg(mem)
+				}
 			case OpInterLECall:
 				code := v.Args[0]
-				mem := x.rewriteArgs(v, 1)
-				v.SetArgs2(code, mem)
+				mem, results := x.rewriteArgs(v, 1)
+				if len(results) == 0 {
+					v.SetArgs2(code, mem)
+				} else {
+					v.SetArgs1(code)
+					v.AddArgs(results...)
+					v.AddArg(mem)
+				}
 			}
 		}
 		if isBlockMultiValueExit(b) {
@@ -942,11 +947,8 @@ func expandCalls(f *Func) {
 			aux := f.OwnAux
 			pos := v.Pos.WithNotStmt()
 			allResults := []*Value{}
-			for j, a := range v.Args {
+			for j, a := range v.Args[:len(v.Args)-1] {
 				i := int64(j)
-				if a == m0 {
-					break
-				}
 				auxType := aux.TypeOfResult(i)
 				auxBase := b.NewValue2A(v.Pos, OpLocalAddr, types.NewPtr(auxType), aux.results[i].Name, x.sp, mem)
 				auxOffset := int64(0)
@@ -978,11 +980,10 @@ func expandCalls(f *Func) {
 						result = &allResults
 					}
 					rc.init(aRegs, aux.abiInfo, result, auxBase)
-					// TODO REGISTER
 					mem = x.storeArgOrLoad(v.Pos, b, a, mem, aux.TypeOfResult(i), auxOffset, 0, rc)
-					// TODO append mem to Result, update type
 				}
 			}
+			// TODO REGISTER -- keep the Result for block control, splice in contents of AllResults
 			b.SetControl(mem)
 			v.reset(OpInvalid) // otherwise it can have a mem operand which will fail check(), even though it is dead.
 		}