compiler: support basic inlining

pkg/compiler/inline.go

@@ -0,0 +1,49 @@
+package compiler
+
+import (
+	"go/ast"
+	"go/types"
+
+	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
+	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
+)
+
+// inlineCall inlines call of n for function represented by f.
+// Call `f(a,b)` for definition `func f(x,y int)` is translated to block:
+// {
+//    x := a
+//    y := b
+//    <inline body of f directly>
+// }
+func (c *codegen) inlineCall(f *funcScope, n *ast.CallExpr) {
+	pkg := c.buildInfo.program.Package(f.pkg.Path())
+	sig := c.typeOf(n.Fun).(*types.Signature)
+
+	// Arguments need to be walked with the current scope,
+	// while stored in the new.
+	oldScope := c.scope.vars.locals
+	c.scope.vars.newScope()
+	newScope := c.scope.vars.locals
+	defer c.scope.vars.dropScope()
+	for i := range n.Args {
+		c.scope.vars.locals = oldScope
+		ast.Walk(c, n.Args[i])
+		c.scope.vars.locals = newScope
+		name := sig.Params().At(i).Name()
+		c.scope.newLocal(name)
+		c.emitStoreVar("", name)
+	}
+
+	c.pkgInfoInline = append(c.pkgInfoInline, pkg)
+	oldMap := c.importMap
+	c.fillImportMap(f.file, pkg.Pkg)
+	ast.Inspect(f.decl, c.scope.analyzeVoidCalls)
+	ast.Walk(c, f.decl.Body)
+	if c.scope.voidCalls[n] {
+		for i := 0; i < f.decl.Type.Results.NumFields(); i++ {
+			emit.Opcodes(c.prog.BinWriter, opcode.DROP)
+		}
+	}
+	c.importMap = oldMap
+	c.pkgInfoInline = c.pkgInfoInline[:len(c.pkgInfoInline)-1]
+}