proc: simplify next/step/stepout condition code

Adds a library of utility functions to generated breakpoint conditions
for next, step and stepout.

pkg/astutil/astutil.go

@@ -0,0 +1,40 @@
+// This package contains utility functions used by pkg/proc to generate
+// ast.Expr expressions.
+
+package astutil
+
+import (
+	"go/ast"
+	"go/token"
+	"strconv"
+)
+
+// Eql returns an expression evaluating 'x == y'.
+func Eql(x, y ast.Expr) *ast.BinaryExpr {
+	return &ast.BinaryExpr{Op: token.EQL, X: x, Y: y}
+}
+
+// Sel returns an expression evaluating 'x.sel'.
+func Sel(x ast.Expr, sel string) *ast.SelectorExpr {
+	return &ast.SelectorExpr{X: x, Sel: &ast.Ident{Name: sel}}
+}
+
+// PkgVar returns an expression evaluating 'pkg.v'.
+func PkgVar(pkg, v string) *ast.SelectorExpr {
+	return &ast.SelectorExpr{X: &ast.Ident{Name: pkg}, Sel: &ast.Ident{Name: v}}
+}
+
+// Int returns an expression representing the integer 'n'.
+func Int(n int64) *ast.BasicLit {
+	return &ast.BasicLit{Kind: token.INT, Value: strconv.FormatInt(n, 10)}
+}
+
+// And returns an expression evaluating 'x && y'.
+func And(x, y ast.Expr) *ast.BinaryExpr {
+	return &ast.BinaryExpr{Op: token.LAND, X: x, Y: y}
+}
+
+// Or returns an expression evaluating 'x || y'.
+func Or(x, y ast.Expr) *ast.BinaryExpr {
+	return &ast.BinaryExpr{Op: token.LOR, X: x, Y: y}
+}

pkg/proc/target_exec.go

@@ -7,8 +7,8 @@ import (
 	"go/ast"
 	"go/token"
 	"path/filepath"
-	"strconv"
 
+	"github.com/go-delve/delve/pkg/astutil"
 	"github.com/go-delve/delve/pkg/dwarf/reader"
 )
 
@@ -289,39 +289,11 @@ func sameGoroutineCondition(g *G) ast.Expr {
 	if g == nil {
 		return nil
 	}
-	return &ast.BinaryExpr{
-		Op: token.EQL,
-		X: &ast.SelectorExpr{
-			X: &ast.SelectorExpr{
-				X:   &ast.Ident{Name: "runtime"},
-				Sel: &ast.Ident{Name: "curg"},
-			},
-			Sel: &ast.Ident{Name: "goid"},
-		},
-		Y: &ast.BasicLit{Kind: token.INT, Value: strconv.Itoa(g.ID)},
-	}
-}
-
-func frameoffCondition(frameoff int64) ast.Expr {
-	return &ast.BinaryExpr{
-		Op: token.EQL,
-		X: &ast.SelectorExpr{
-			X:   &ast.Ident{Name: "runtime"},
-			Sel: &ast.Ident{Name: "frameoff"},
-		},
-		Y: &ast.BasicLit{Kind: token.INT, Value: strconv.FormatInt(frameoff, 10)},
-	}
+	return astutil.Eql(astutil.Sel(astutil.PkgVar("runtime", "curg"), "goid"), astutil.Int(int64(g.ID)))
 }
 
-func andFrameoffCondition(cond ast.Expr, frameoff int64) ast.Expr {
-	if cond == nil {
-		return nil
-	}
-	return &ast.BinaryExpr{
-		Op: token.LAND,
-		X:  cond,
-		Y:  frameoffCondition(frameoff),
-	}
+func frameoffCondition(frame *Stackframe) ast.Expr {
+	return astutil.Eql(astutil.PkgVar("runtime", "frameoff"), astutil.Int(frame.FrameOffset()))
 }
 
 // StepOut will continue until the current goroutine exits the
@@ -384,7 +356,7 @@ func (dbp *Target) StepOut() error {
 
 	if topframe.Ret != 0 {
 		topframe, retframe := skipAutogeneratedWrappersOut(selg, curthread, &topframe, &retframe)
-		retFrameCond := andFrameoffCondition(sameGCond, retframe.FrameOffset())
+		retFrameCond := astutil.And(sameGCond, frameoffCondition(retframe))
 		bp, err := allowDuplicateBreakpoint(dbp.SetBreakpoint(topframe.Ret, NextBreakpoint, retFrameCond))
 		if err != nil {
 			return err
@@ -537,7 +509,7 @@ func next(dbp *Target, stepInto, inlinedStepOut bool) error {
 		return err
 	}
 
-	sameFrameCond := andFrameoffCondition(sameGCond, topframe.FrameOffset())
+	sameFrameCond := astutil.And(sameGCond, frameoffCondition(&topframe))
 
 	if stepInto && !backward {
 		err := setStepIntoBreakpoints(dbp, text, topframe, sameGCond)
@@ -618,18 +590,10 @@ func next(dbp *Target, stepInto, inlinedStepOut bool) error {
 
 	if !topframe.Inlined {
 		topframe, retframe := skipAutogeneratedWrappersOut(selg, curthread, &topframe, &retframe)
-		retFrameCond := andFrameoffCondition(sameGCond, retframe.FrameOffset())
+		retFrameCond := astutil.And(sameGCond, frameoffCondition(retframe))
 		var sameOrRetFrameCond ast.Expr
 		if sameGCond != nil {
-			sameOrRetFrameCond = &ast.BinaryExpr{
-				Op: token.LAND,
-				X:  sameGCond,
-				Y: &ast.BinaryExpr{
-					Op: token.LOR,
-					X:  frameoffCondition(topframe.FrameOffset()),
-					Y:  frameoffCondition(retframe.FrameOffset()),
-				},
-			}
+			sameOrRetFrameCond = astutil.And(sameGCond, astutil.Or(frameoffCondition(topframe), frameoffCondition(retframe)))
 		}
 
 		// Add a breakpoint on the return address for the current frame.