all: introduce call properties

Call properties let us specify how each individual call within a program
must be executed. So far the only way to enforce extra rules was to pass
extra program-level properties (e.g. that is how fault injection was done).
However, it entangles the logic and not flexible enough.

Implement an ability to pass properties along with each individual call.

1 files changed, 16 insertions, 1 deletions

diff --git a/prog/encodingexec.go b/prog/encodingexec.go
index e0c7ec59d..296fcf0cf 100644
--- a/prog/encodingexec.go
+++ b/prog/encodingexec.go
@@ -6,7 +6,7 @@
 
 // Exec format is an sequence of uint64's which encodes a sequence of calls.
 // The sequence is terminated by a speciall call execInstrEOF.
-// Each call is (call ID, copyout index, number of arguments, arguments...).
+// Each call is (call ID, call props, copyout index, number of arguments, arguments...).
 // Each argument is (type, size, value).
 // There are 4 types of arguments:
 //  - execArgConst: value is const value
@@ -22,6 +22,7 @@ package prog
 import (
 	"errors"
 	"fmt"
+	"reflect"
 	"sort"
 )
 
@@ -89,6 +90,8 @@ func (w *execContext) serializeCall(c *Call) {
 	w.writeChecksums()
 	// Generate the call itself.
 	w.write(uint64(c.Meta.ID))
+	// Generate call properties fragment.
+	w.writeCallProps(c.Props)
 	if c.Ret != nil && len(c.Ret.uses) != 0 {
 		if _, ok := w.args[c.Ret]; ok {
 			panic("argInfo is already created for return value")
@@ -103,6 +106,7 @@ func (w *execContext) serializeCall(c *Call) {
 	for _, arg := range c.Args {
 		w.writeArg(arg)
 	}
+
 	// Generate copyout instructions that persist interesting return values.
 	w.writeCopyout(c)
 }
@@ -124,6 +128,17 @@ type argInfo struct {
 	Ret  bool
 }
 
+func (w *execContext) writeCallProps(props CallProps) {
+	props.ForeachProp(func(_, _ string, value reflect.Value) {
+		switch kind := value.Kind(); kind {
+		case reflect.Int:
+			w.write(uint64(value.Int()))
+		default:
+			panic("Unsupported (yet) kind: " + kind.String())
+		}
+	})
+}
+
 func (w *execContext) writeCopyin(c *Call) {
 	ForeachArg(c, func(arg Arg, ctx *ArgCtx) {
 		if ctx.Base == nil {