Front-end support for unions; partial fix for p4lang#561

testdata/p4_16_errors/issue561-1.p4

@@ -0,0 +1,33 @@
+/*
+Copyright 2017 VMware, Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+header H1 { bit<32> f; }
+header H2 { bit<32> g; }
+
+header_union U {
+    H1 h1;
+    H2 h2;
+}
+
+control ct();
+package top(ct _ct);
+
+control c() {
+    apply {
+        U u = { { 10 }, { 20 } };  // illegal to initialize unions
+        u.setValid(); // no such method
+    }
+}
+top(c()) main;

testdata/p4_16_errors_outputs/issue561-1.p4

@@ -0,0 +1,23 @@
+header H1 {
+    bit<32> f;
+}
+
+header H2 {
+    bit<32> g;
+}
+
+header_union U {
+    H1 h1;
+    H2 h2;
+}
+
+control ct();
+package top(ct _ct);
+control c() {
+    apply {
+        U u = { { 10 }, { 20 } };
+        u.setValid();
+    }
+}
+
+top(c()) main;

testdata/p4_16_errors_outputs/issue561-1.p4-stderr

@@ -0,0 +1,18 @@
+../testdata/p4_16_errors/issue561-1.p4(29): error: u: Cannot unify Tuple(2) to header_union U
+        U u = { { 10 }, { 20 } }; // illegal to initialize unions
+        ^^^^^^^^^^^^^^^^^^^^^^^^^
+../testdata/p4_16_errors/issue561-1.p4(29)
+        U u = { { 10 }, { 20 } }; // illegal to initialize unions
+              ^^^^^^^^^^^^^^^^^^
+../testdata/p4_16_errors/issue561-1.p4(19)
+header_union U {
+             ^
+../testdata/p4_16_errors/issue561-1.p4(19): error: Structure header_union U does not have a field setValid
+header_union U {
+             ^
+../testdata/p4_16_errors/issue561-1.p4(30)
+        u.setValid(); // no such method
+          ^^^^^^^^
+../testdata/p4_16_errors/issue561-1.p4(30): error: Could not find type of u.setValid
+        u.setValid(); // no such method
+        ^^^^^^^^^^

testdata/p4_16_samples/issue561.p4

@@ -0,0 +1,48 @@
+/*
+Copyright 2017 VMware, Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+header H1 { bit<32> f; }
+header H2 { bit<32> g; }
+
+header_union U {
+    H1 h1;
+    H2 h2;
+}
+
+control ct(out bit<32> b);
+package top(ct _ct);
+
+control c(out bit<32> x) {
+    apply {
+        U u;
+        U[2] u2;
+
+        bool b = u.isValid();
+        b = b || u.h1.isValid();
+
+        x = u.h1.f + u.h2.g;
+        u.h1.setValid();
+        u.h1.f = 0;
+        x = x + u.h1.f;
+
+        u.h2.g = 0;
+        x = x + u.h2.g;
+
+        u2[0].h1.setValid();
+        u2[0].h1.f = 2;
+        x = x + u2[1].h2.g + u2[0].h1.f;
+    }
+}
+top(c()) main;

testdata/p4_16_samples_outputs/issue561-first.p4

@@ -0,0 +1,34 @@
+header H1 {
+    bit<32> f;
+}
+
+header H2 {
+    bit<32> g;
+}
+
+header_union U {
+    H1 h1;
+    H2 h2;
+}
+
+control ct(out bit<32> b);
+package top(ct _ct);
+control c(out bit<32> x) {
+    apply {
+        U u;
+        U[2] u2;
+        bool b = u.isValid();
+        b = b || u.h1.isValid();
+        x = u.h1.f + u.h2.g;
+        u.h1.setValid();
+        u.h1.f = 32w0;
+        x = x + u.h1.f;
+        u.h2.g = 32w0;
+        x = x + u.h2.g;
+        u2[0].h1.setValid();
+        u2[0].h1.f = 32w2;
+        x = x + u2[1].h2.g + u2[0].h1.f;
+    }
+}
+
+top(c()) main;

testdata/p4_16_samples_outputs/issue561-frontend.p4

@@ -0,0 +1,35 @@
+header H1 {
+    bit<32> f;
+}
+
+header H2 {
+    bit<32> g;
+}
+
+header_union U {
+    H1 h1;
+    H2 h2;
+}
+
+control ct(out bit<32> b);
+package top(ct _ct);
+control c(out bit<32> x) {
+    U u_0;
+    U[2] u2_0;
+    bool b_0;
+    apply {
+        b_0 = u_0.isValid();
+        u_0.h1.isValid();
+        x = u_0.h1.f + u_0.h2.g;
+        u_0.h1.setValid();
+        u_0.h1.f = 32w0;
+        x = x + u_0.h1.f;
+        u_0.h2.g = 32w0;
+        x = x + u_0.h2.g;
+        u2_0[0].h1.setValid();
+        u2_0[0].h1.f = 32w2;
+        x = x + u2_0[1].h2.g + u2_0[0].h1.f;
+    }
+}
+
+top(c()) main;

testdata/p4_16_samples_outputs/issue561-midend.p4

@@ -0,0 +1,42 @@
+header H1 {
+    bit<32> f;
+}
+
+header H2 {
+    bit<32> g;
+}
+
+header_union U {
+    H1 h1;
+    H2 h2;
+}
+
+control ct(out bit<32> b);
+package top(ct _ct);
+control c(out bit<32> x) {
+    U u;
+    U[2] u2;
+    @hidden action act() {
+        u.h1.isValid();
+        x = u.h1.f + u.h2.g;
+        u.h1.setValid();
+        u.h1.f = 32w0;
+        x = x + u.h1.f;
+        u.h2.g = 32w0;
+        x = x + u.h2.g;
+        u2[0].h1.setValid();
+        u2[0].h1.f = 32w2;
+        x = x + u2[1].h2.g + u2[0].h1.f;
+    }
+    @hidden table tbl_act {
+        actions = {
+            act();
+        }
+        const default_action = act();
+    }
+    apply {
+        tbl_act.apply();
+    }
+}
+
+top(c()) main;

testdata/p4_16_samples_outputs/issue561.p4

@@ -0,0 +1,34 @@
+header H1 {
+    bit<32> f;
+}
+
+header H2 {
+    bit<32> g;
+}
+
+header_union U {
+    H1 h1;
+    H2 h2;
+}
+
+control ct(out bit<32> b);
+package top(ct _ct);
+control c(out bit<32> x) {
+    apply {
+        U u;
+        U[2] u2;
+        bool b = u.isValid();
+        b = b || u.h1.isValid();
+        x = u.h1.f + u.h2.g;
+        u.h1.setValid();
+        u.h1.f = 0;
+        x = x + u.h1.f;
+        u.h2.g = 0;
+        x = x + u.h2.g;
+        u2[0].h1.setValid();
+        u2[0].h1.f = 2;
+        x = x + u2[1].h2.g + u2[0].h1.f;
+    }
+}
+
+top(c()) main;

testdata/p4_16_samples_outputs/issue561.p4-stderr

@@ -0,0 +1,9 @@
+../testdata/p4_16_samples/issue561.p4(35): warning: u.h1.f may be uninitialized
+        x = u.h1.f + u.h2.g;
+            ^^^^^^
+../testdata/p4_16_samples/issue561.p4(35): warning: u.h2.g may be uninitialized
+        x = u.h1.f + u.h2.g;
+                     ^^^^^^
+../testdata/p4_16_samples/issue561.p4(45): warning: [].h2.g may be uninitialized
+        x = x + u2[1].h2.g + u2[0].h1.f;
+                ^^^^^^^^^^

testdata/p4_16_samples_outputs/struct-first.p4

@@ -13,9 +13,13 @@ struct S {
     T s2;
 }
 
+struct Empty {
+}
+
 const T t = { 32s10, 32s20 };
 const S s = { { 32s15, 32s25 }, { 32s10, 32s20 } };
 const int<32> x = 32s10;
 const int<32> y = 32s25;
 const int<32> w = 32s10;
 const T t1 = { 32s15, 32s25 };
+const Empty e = {  };

testdata/p4_16_samples_outputs/struct-frontend.p4

@@ -13,3 +13,6 @@ struct S {
     T s2;
 }
 
+struct Empty {
+}
+

testdata/p4_16_samples_outputs/struct.p4

@@ -13,9 +13,13 @@ struct S {
     T s2;
 }
 
+struct Empty {
+}
+
 const T t = { 32s10, 32s20 };
 const S s = { { 32s15, 32s25 }, t };
 const int<32> x = t.t1;
 const int<32> y = s.s1.t2;
 const int<32> w = .t.t1;
 const T t1 = s.s1;
+const Empty e = {  };