From 986fa4971cf27c597fa4baa23e88ce340187c2d0 Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Sun, 26 Apr 2020 15:34:25 +0200
Subject: prog: don't squash objects that contain pointers

Squashing pointers creates several problems:
- we need to generate pointer types on the fly,
  something we don't do in any other contexts,
  it complicates other changes
- pointers are very special as values,
  if we change size of the surrounding blobs,
  offsets changes and we will use something that's
  not a pointer as pointer and vise versa,
  boths things are most likley very bad as inputs
- squashing/any implementation is just too complex

This disqualifies several types for squashing:

    <         alloc_pd_cmd
    <         arpt_replace
    <         array[cmsghdr_rds]
    <         create_cq_cmd
    <         create_flow_cmd
    <         create_qp_cmd
    <         create_srq_cmd
    <         ebt_counters_info
    <         ip6t_replace
    <         ipt_replace
    <         mlx5_alloc_pd_cmd
    <         mlx5_create_dv_qp_cmd
    <         open_xrcd_cmd
    <         post_recv_cmd
    <         post_send_cmd
    <         post_srq_recv_cmd
    <         query_qp_cmd
    <         query_srq_cmd
    <         reg_mr_cmd
    <         rereg_mr_cmd
    <         resize_cq_cmd
    <         usbdevfs_urb
    <         vhost_memory
    <         vusb_connect_descriptors

and adds few new:

    >         binder_objects
    >         query_qp_resp
    >         resize_cq_resp
    >         usb_bos_descriptor
    >         usb_string_descriptor

Overall this looks sane.
Majority is still unchanged.
---
 prog/any.go      | 31 ++++++-------------------------
 prog/any_test.go |  4 ++--
 sys/test/any.txt |  8 +++-----
 3 files changed, 11 insertions(+), 32 deletions(-)

diff --git a/prog/any.go b/prog/any.go
index a9ecdb489..f8593395a 100644
--- a/prog/any.go
+++ b/prog/any.go
@@ -28,8 +28,6 @@ type anyTypes struct {
 // resource ANYRES64[int64]: 0xffffffffffffffff, 0
 // ANY [
 // 	bin	array[int8]
-// 	ptr	ptr[in, array[ANY], opt]
-// 	ptr64	ptr64[in, array[ANY], opt]
 // 	res16	ANYRES16
 // 	res32	ANYRES32
 // 	res64	ANYRES64
@@ -106,8 +104,6 @@ func initAnyTypes(target *Target) {
 		},
 		Fields: []Type{
 			target.any.blob,
-			target.any.ptrPtr,
-			target.any.ptr64,
 			target.any.res16,
 			target.any.res32,
 			target.any.res64,
@@ -160,26 +156,23 @@ func (target *Target) isComplexPtr(arg *PointerArg) bool {
 	if target.isAnyPtr(arg.Type()) {
 		return true
 	}
-	res := false
+	complex, hasPtr := false, false
 	ForeachSubArg(arg.Res, func(a1 Arg, ctx *ArgCtx) {
 		switch typ := a1.Type().(type) {
 		case *StructType:
 			if typ.Varlen() {
-				res = true
-				ctx.Stop = true
+				complex = true
 			}
 		case *UnionType:
 			if typ.Varlen() && len(typ.Fields) > 5 {
-				res = true
-				ctx.Stop = true
+				complex = true
 			}
 		case *PtrType:
-			if a1 != arg {
-				ctx.Stop = true
-			}
+			hasPtr = true
+			ctx.Stop = true
 		}
 	})
-	return res
+	return complex && !hasPtr
 }
 
 func (target *Target) CallContainsAny(c *Call) (res bool) {
@@ -231,18 +224,6 @@ func (target *Target) squashPtrImpl(a Arg, elems *[]Arg) {
 		target.squashConst(arg, elems)
 	case *ResultArg:
 		target.squashResult(arg, elems)
-	case *PointerArg:
-		if arg.Res != nil {
-			target.squashPtr(arg, false)
-			*elems = append(*elems, MakeUnionArg(target.any.union, arg))
-		} else {
-			elem := target.ensureDataElem(elems)
-			addr := target.PhysicalAddr(arg)
-			for i := uint64(0); i < arg.Size(); i++ {
-				elem.data = append(elem.Data(), byte(addr))
-				addr >>= 8
-			}
-		}
 	case *UnionArg:
 		if !arg.Type().Varlen() {
 			pad = arg.Size() - arg.Option.Size()
diff --git a/prog/any_test.go b/prog/any_test.go
index eaa5bddf6..968d1624a 100644
--- a/prog/any_test.go
+++ b/prog/any_test.go
@@ -44,8 +44,8 @@ func TestSquash(t *testing.T) {
 		squashed string
 	}{
 		{
-			`foo$any0(&(0x7f0000000000)={0x11, 0x11223344, 0x2233, 0x1122334455667788, {0x1, 0x7, 0x1, 0x1, 0x1bc, 0x4}, [{0x0, @res32=0x0, 0x0, @i8=0x44, "aabb"}, {0x0, @res64=0x1, 0x0, @i32=0x11223344, "1122334455667788"}]})`,
-			`foo$any0(&(0x7f0000000000)=ANY=[@ANYBLOB="1100000044332211223300000000000088776655443322117d00bc110000000000000000", @ANYRES32=0x0, @ANYBLOB="00000000000000000000000044aabb000000000000000000", @ANYRES64=0x1, @ANYBLOB="000000000000000044332211112233445566778800000000"])`,
+			`foo$any0(&(0x7f0000000000)={0x11, 0x11223344, 0x2233, 0x1122334455667788, {0x1, 0x7, 0x1, 0x1, 0x1bc, 0x4}, [{@res32=0x0, @i8=0x44, "aabb"}, {@res64=0x1, @i32=0x11223344, "1122334455667788"}]})`,
+			`foo$any0(&(0x7f0000000000)=ANY=[@ANYBLOB="1100000044332211223300000000000088776655443322117d00bc11", @ANYRES32=0x0, @ANYBLOB="0000000044aabb00", @ANYRES64=0x1, @ANYBLOB="44332211112233445566778800000000"])`,
 		},
 	}
 	for i, test := range tests {
diff --git a/sys/test/any.txt b/sys/test/any.txt
index cc71f9940..060992c3f 100644
--- a/sys/test/any.txt
+++ b/sys/test/any.txt
@@ -18,11 +18,9 @@ any0 {
 } [align[8]]
 
 any1 {
-	f1	ptr[in, int8, opt]
-	f2	anyunion0
-	f3	ptr64[in, int8, opt]
-	f4	anyunion1
-	f5	array[int8]
+	f1	anyunion0
+	f2	anyunion1
+	f3	array[int8]
 } [packed, align[2]]
 
 anyunion0 [
-- 
cgit mrf-deployment