compiler: support flags as int first argument

This commit adds support for the following syntax:

    int_flags = 1, 5, 8, 9
    int32[int_flags]

which is equivalent to:

    int_flags = 1, 5, 8, 9
    flags[int_flags, int32]

The second int type argument, align, is not allowed if the first
argument is a flag. The compiler will also error if the first argument
appears to be a flag (is ident and has no colon), but can't be found in
the map of flags.

Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/pkg/compiler/consts.go b/pkg/compiler/consts.go
index e9f7227e7..6fe3e7bc0 100644
--- a/pkg/compiler/consts.go
+++ b/pkg/compiler/consts.go
@@ -123,6 +123,13 @@ func (comp *compiler) addConst(infos map[string]*constInfo, pos ast.Pos, name st
 	if _, builtin := comp.builtinConsts[name]; builtin {
 		return
 	}
+	// In case of intN[identA], identA may refer to a constant or to a set of
+	// flags. To avoid marking all flags as constants, we must check here
+	// whether identA refers to a flag. We have a check in the compiler to
+	// ensure an identifier can never refer to both a constant and flags.
+	if _, isFlag := comp.intFlags[name]; isFlag {
+		return
+	}
 	info := getConstInfo(infos, pos)
 	info.consts[name] = &Const{
 		Pos:  pos,
@@ -297,6 +304,11 @@ func (comp *compiler) patchConst(val *uint64, id *string, consts map[string]uint
 		*val = v
 		return true
 	}
+	// This check is necessary because in intN[identA], identA may be a
+	// constant or a set of flags.
+	if _, isFlag := comp.intFlags[*id]; isFlag {
+		return true
+	}
 	if missing != nil && *missing == "" {
 		*missing = *id
 	}