Check if 'match_kind.exact' is defined when expanding switch statements

midend/eliminateSwitch.cpp

@@ -19,6 +19,21 @@ limitations under the License.
 
 namespace P4 {
 
+const IR::Node* DoEliminateSwitch::postorder(IR::P4Program* program) {
+    if (!exactNeeded)
+        return program;
+    for (auto *obj : program->objects) {
+        if (auto *match_kind = obj->to<IR::Declaration_MatchKind>()) {
+            if (match_kind->getDeclByName(P4CoreLibrary::instance.exactMatch.Id()))
+                return program;
+        }
+    }
+    ::error(ErrorType::ERR_NOT_FOUND,
+            "Could not find declaration for 'match_kind.exact', which is needed to implement "
+            "switch statements; did you include core.p4?");
+    return program;
+}
+
 const IR::Node* DoEliminateSwitch::postorder(IR::P4Control* control) {
     for (auto a : toInsert)
         control->controlLocals.push_back(a);
@@ -54,6 +69,7 @@ const IR::Node* DoEliminateSwitch::postorder(IR::SwitchStatement* statement) {
     auto tableKeyEl = new IR::KeyElement(
         src, new IR::PathExpression(key),
         new IR::PathExpression(P4CoreLibrary::instance.exactMatch.Id()));
+    exactNeeded = true;
     IR::IndexedVector<IR::ActionListElement> actionsList;
     IR::IndexedVector<IR::Property> properties;
     IR::Vector<IR::SwitchCase> cases;

midend/eliminateSwitch.h

@@ -79,11 +79,14 @@ class DoEliminateSwitch final : public Transform {
     const TypeMap* typeMap;
     std::vector<const IR::Declaration*> toInsert;
  public:
-    explicit DoEliminateSwitch(ReferenceMap* refMap, const TypeMap* typeMap):
+    bool exactNeeded = false;
+
+    DoEliminateSwitch(ReferenceMap* refMap, const TypeMap* typeMap):
             refMap(refMap), typeMap(typeMap)
     { setName("DoEliminateSwitch"); CHECK_NULL(refMap); CHECK_NULL(typeMap); }
     const IR::Node* postorder(IR::SwitchStatement* statement) override;
     const IR::Node* postorder(IR::P4Control* control) override;
+    const IR::Node* postorder(IR::P4Program* program) override;
 };
 
 class EliminateSwitch final : public PassManager {

testdata/p4_16_errors/issue3613.p4

@@ -0,0 +1,11 @@
+control c(in bit<4> a)
+{
+  apply {
+    switch (a) {
+      4w0: {}
+    }
+  }
+}
+control ct(in bit<4> a);
+package pt(ct t);
+pt(c()) main;

testdata/p4_16_errors_outputs/issue3613-first.p4

@@ -0,0 +1,12 @@
+control c(in bit<4> a) {
+    apply {
+        switch (a) {
+            4w0: {
+            }
+        }
+    }
+}
+
+control ct(in bit<4> a);
+package pt(ct t);
+pt(c()) main;

testdata/p4_16_errors_outputs/issue3613-frontend.p4

@@ -0,0 +1,12 @@
+control c(in bit<4> a) {
+    apply {
+        switch (a) {
+            4w0: {
+            }
+        }
+    }
+}
+
+control ct(in bit<4> a);
+package pt(ct t);
+pt(c()) main;

testdata/p4_16_errors_outputs/issue3613.p4

@@ -0,0 +1,12 @@
+control c(in bit<4> a) {
+    apply {
+        switch (a) {
+            4w0: {
+            }
+        }
+    }
+}
+
+control ct(in bit<4> a);
+package pt(ct t);
+pt(c()) main;

testdata/p4_16_errors_outputs/issue3613.p4-stderr

@@ -0,0 +1 @@
+[--Werror=not-found] error: Could not find declaration for 'match_kind.exact', which is needed to implement switch statements; did you include core.p4?