Reduce peak memory usage by clearing encoded instructions in builder

The builder will be kept alive until the replay is done on the device,
while the encoded instructions and resources can be freed before the
replay gets started.

gapis/api/vulkan/find_issues.go

@@ -89,7 +89,6 @@ func (t *findIssues) reportTo(r replay.Result) { t.res = append(t.res, r) }
 
 func (t *findIssues) Transform(ctx context.Context, id api.CmdID, cmd api.Cmd, out transform.Writer) {
 	ctx = log.Enter(ctx, "findIssues")
-	cb := CommandBuilder{Thread: cmd.Thread(), Arena: t.state.Arena}
 
 	mutateErr := cmd.Mutate(ctx, id, t.state, nil /* no builder */)
 	if mutateErr != nil {
@@ -98,6 +97,7 @@ func (t *findIssues) Transform(ctx context.Context, id api.CmdID, cmd api.Cmd, o
 	}
 
 	s := out.State()
+	cb := CommandBuilder{Thread: cmd.Thread(), Arena: out.State().Arena}
 	l := s.MemoryLayout
 	allocated := []api.AllocResult{}
 	defer func() {
@@ -269,7 +269,7 @@ func (t *findIssues) Transform(ctx context.Context, id api.CmdID, cmd api.Cmd, o
 }
 
 func (t *findIssues) Flush(ctx context.Context, out transform.Writer) {
-	cb := CommandBuilder{Thread: 0, Arena: t.state.Arena}
+	cb := CommandBuilder{Thread: 0, Arena: out.State().Arena}
 	for inst, ch := range t.reportCallbacks {
 		out.MutateAndWrite(ctx, api.CmdNoID, cb.ReplayDestroyVkDebugReportCallback(inst, ch))
 		// It is safe to delete keys in loop in Go

gapis/api/vulkan/replay.go

@@ -674,8 +674,11 @@ func (a API) Replay(
 		transforms.Add(overdraw)
 	}
 
+	if issues == nil {
+		transforms.Add(readFramebuffer, injector)
+	}
+
 	// Cleanup
-	transforms.Add(readFramebuffer, injector)
 	transforms.Add(&destroyResourcesAtEOS{})
 
 	if config.DebugReplay {

gapis/replay/builder/builder.go

@@ -664,6 +664,19 @@ func (b *Builder) Build(ctx context.Context) (gapir.Payload, PostDataHandler, No
 		})
 	}
 
+	// Clear the builder.
+	defer func() {
+		b.resourceIDToIdx = nil
+		b.threadIDToIdx = nil
+		b.resources = nil
+		b.reservedMemory = memory.RangeList{}
+		b.pointerMemory = memory.RangeList{}
+		b.mappedMemory = mappedMemoryRangeList{}
+		b.instructions = nil
+		b.stack = nil
+		b.Remappings = nil
+	}()
+
 	return payload, handlePost, handleNotification, nil
 }