Add a pass which converts struct expressions with Type_Header to head…

…er expressions.
p4lang · Nov 15, 2023 · 6f91dae · 6f91dae
1 parent 6845c48
commit 6f91dae
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Showing 4 changed files with 51 additions and 1 deletion.
diff --git a/backends/p4tools/common/CMakeLists.txt b/backends/p4tools/common/CMakeLists.txt
@@ -12,6 +12,7 @@ set(
 
   compiler/compiler_target.cpp
   compiler/convert_hs_index.cpp
+  compiler/convert_struct_expr.cpp
   compiler/convert_varbits.cpp
   compiler/midend.cpp
   compiler/reachability.cpp

diff --git a/backends/p4tools/common/compiler/convert_struct_expr.cpp b/backends/p4tools/common/compiler/convert_struct_expr.cpp
@@ -0,0 +1,24 @@
+#include "backends/p4tools/common/compiler/convert_struct_expr.h"
+
+#include "ir/irutils.h"
+
+namespace P4Tools {
+
+const IR::Node *ConvertStructExpr::postorder(IR::StructExpression *expr) {
+    auto structType = expr->type;
+    if (structType->is<IR::Type_Name>()) {
+        structType = typeMap->getTypeType(structType, true);
+    }
+    if (structType->is<IR::Type_Header>()) {
+        auto structExpr = expr->to<IR::StructExpression>();
+        return new IR::HeaderExpression(structExpr->srcInfo, expr->type, expr->type,
+                                        structExpr->components, IR::getBoolLiteral(true));
+    }
+    return expr;
+}
+
+ConvertStructExpr::ConvertStructExpr(const P4::TypeMap *typeMap) : typeMap(typeMap) {
+    setName("ConvertStructExpr");
+    visitDagOnce = false;
+}
+}  // namespace P4Tools
diff --git a/backends/p4tools/common/compiler/convert_struct_expr.h b/backends/p4tools/common/compiler/convert_struct_expr.h
@@ -0,0 +1,23 @@
+#ifndef BACKENDS_P4TOOLS_COMMON_COMPILER_CONVERT_STRUCT_EXPR_H_
+#define BACKENDS_P4TOOLS_COMMON_COMPILER_CONVERT_STRUCT_EXPR_H_
+
+#include "frontends/p4/typeMap.h"
+#include "ir/ir.h"
+#include "ir/node.h"
+#include "ir/visitor.h"
+
+namespace P4Tools {
+
+class ConvertStructExpr : public Transform {
+ private:
+    const P4::TypeMap *typeMap;
+
+ public:
+    explicit ConvertStructExpr(const P4::TypeMap *typeMap);
+
+    const IR::Node *postorder(IR::StructExpression *expr) override;
+};
+
+}  // namespace P4Tools
+
+#endif /* BACKENDS_P4TOOLS_COMMON_COMPILER_CONVERT_STRUCT_EXPR_H_ */
diff --git a/backends/p4tools/common/compiler/midend.cpp b/backends/p4tools/common/compiler/midend.cpp
@@ -1,5 +1,6 @@
 #include "backends/p4tools/common/compiler/midend.h"
 
+#include "backends/p4tools/common/compiler/convert_struct_expr.h"
 #include "backends/p4tools/common/compiler/convert_varbits.h"
 #include "frontends/common/constantFolding.h"
 #include "frontends/common/options.h"
@@ -30,7 +31,6 @@
 #include "midend/orderArguments.h"
 #include "midend/parserUnroll.h"
 #include "midend/removeLeftSlices.h"
-#include "midend/removeMiss.h"
 #include "midend/removeSelectBooleans.h"
 #include "midend/replaceSelectRange.h"
 #include "midend/simplifyBitwise.h"
@@ -162,6 +162,8 @@ void MidEnd::addDefaultPasses() {
         new P4::HSIndexSimplifier(&refMap, &typeMap),
         // Convert Type_Varbits into a type that contains information about the assigned width.
         new ConvertVarbits(),
+        // Convert any StructExpressions with Type_Header into a HeaderExpression.
+        new ConvertStructExpr(&typeMap),
         // Cast all boolean table keys with a bit<1>.
         new P4::CastBooleanTableKeys(),
     });