From 3306162acd9e60e06c5574dc28d67df71a78cbad Mon Sep 17 00:00:00 2001
From: Fabian Ruffy <5960321+fruffy@users.noreply.github.com>
Date: Fri, 30 Aug 2024 13:44:43 +0200
Subject: [PATCH] Make isSystemFile() part of the parser options file. (#4888)

* Remove a stray print in the smith code. (#4891)

Signed-off-by: fruffy <fruffy@nyu.edu>

* Make isSystemFile part of the parser options.

Signed-off-by: fruffy <fruffy@nyu.edu>

* Review comments.

Signed-off-by: fruffy <fruffy@nyu.edu>

---------

Signed-off-by: fruffy <fruffy@nyu.edu>
---
 frontends/common/parser_options.cpp |  2 ++
 frontends/common/parser_options.h   |  3 +++
 frontends/p4/toP4/toP4.cpp          | 29 +++++++++++++----------------
 frontends/p4/toP4/toP4.h            |  8 +++++---
 4 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/frontends/common/parser_options.cpp b/frontends/common/parser_options.cpp
index 1a73dd1a470..d598987f0d4 100644
--- a/frontends/common/parser_options.cpp
+++ b/frontends/common/parser_options.cpp
@@ -48,6 +48,8 @@ const char *p4_14includePath = CONFIG_PKGDATADIR "/p4_14include";
 
 using namespace P4::literals;
 
+bool isSystemFile(cstring file) { return file.startsWith(p4includePath); }
+
 void ParserOptions::closeFile(FILE *file) {
     if (file == nullptr) {
         return;
diff --git a/frontends/common/parser_options.h b/frontends/common/parser_options.h
index d57cb0066f0..6ed4ebb159f 100644
--- a/frontends/common/parser_options.h
+++ b/frontends/common/parser_options.h
@@ -36,6 +36,9 @@ namespace P4 {
 extern const char *p4includePath;
 extern const char *p4_14includePath;
 
+/// Try to guess whether a file is a "system" file
+bool isSystemFile(cstring filename);
+
 /// Base class for compiler options.
 /// This class contains the options for the front-ends.
 /// Each back-end should subclass this file.
diff --git a/frontends/p4/toP4/toP4.cpp b/frontends/p4/toP4/toP4.cpp
index 6a8041f6f86..cad9e003b5f 100644
--- a/frontends/p4/toP4/toP4.cpp
+++ b/frontends/p4/toP4/toP4.cpp
@@ -46,18 +46,15 @@ void ToP4::end_apply(const IR::Node *) {
               "inconsistent vectorSeparator");
 }
 
-// Try to guess whether a file is a "system" file
-bool ToP4::isSystemFile(cstring file) {
-    if (noIncludes) return false;
-    if (file.startsWith(p4includePath)) return true;
-    return false;
-}
-
-cstring ToP4::ifSystemFile(const IR::Node *node) {
-    if (!node->srcInfo.isValid()) return nullptr;
+std::optional<cstring> ToP4::ifSystemFile(const IR::Node *node) {
+    if (!node->srcInfo.isValid() || noIncludes) {
+        return std::nullopt;
+    }
     auto sourceFile = node->srcInfo.getSourceFile();
-    if (isSystemFile(sourceFile)) return sourceFile;
-    return nullptr;
+    if (isSystemFile(sourceFile)) {
+        return sourceFile;
+    }
+    return std::nullopt;
 }
 
 namespace {
@@ -153,9 +150,9 @@ bool ToP4::preorder(const IR::P4Program *program) {
     dump(2);
     for (auto a : program->objects) {
         // Check where this declaration originates
-        cstring sourceFile = ifSystemFile(a);
-        if (!a->is<IR::Type_Error>() &&  // errors can come from multiple files
-            sourceFile != nullptr) {
+        auto sourceFileOpt = ifSystemFile(a);
+        // Errors can come from multiple files
+        if (!a->is<IR::Type_Error>() && sourceFileOpt.has_value()) {
             /* FIXME -- when including a user header file (sourceFile !=
              * mainFile), do we want to emit an #include of it or not?  Probably
              * not when translating from P4-14, as that would create a P4-16
@@ -163,7 +160,7 @@ bool ToP4::preorder(const IR::P4Program *program) {
              * allow converting headers independently (is that even possible?).
              * For now we ignore mainFile and don't emit #includes for any
              * non-system header */
-
+            auto sourceFile = sourceFileOpt.value();
             if (includesEmitted.find(sourceFile) == includesEmitted.end()) {
                 if (sourceFile.startsWith(p4includePath)) {
                     const char *p = sourceFile.c_str() + strlen(p4includePath);
@@ -691,7 +688,7 @@ bool ToP4::preorder(const IR::Type_Error *d) {
     dump(1);
     bool first = true;
     for (auto a : *d->getDeclarations()) {
-        if (ifSystemFile(a->getNode()))
+        if (ifSystemFile(a->getNode()).has_value())
             // only print if not from a system file
             continue;
         if (!first) {
diff --git a/frontends/p4/toP4/toP4.h b/frontends/p4/toP4/toP4.h
index f0a8e63bd7e..87e78e7771e 100644
--- a/frontends/p4/toP4/toP4.h
+++ b/frontends/p4/toP4/toP4.h
@@ -17,6 +17,8 @@ limitations under the License.
 #ifndef P4_TOP4_TOP4_H_
 #define P4_TOP4_TOP4_H_
 
+#include <optional>
+
 #include "frontends/common/resolveReferences/resolveReferences.h"
 #include "ir/ir.h"
 #include "ir/visitor.h"
@@ -72,9 +74,9 @@ class ToP4 : public Inspector, ResolutionContext {
         BUG_CHECK(!listTerminators.empty(), "Empty listTerminators");
         listTerminators.pop_back();
     }
-    bool isSystemFile(cstring file);
-    cstring ifSystemFile(const IR::Node *node);  // return file containing node if system file
-    // dump node IR tree up to depth - in the form of a comment
+    /// @returns the file that contains the node, if the node is part of a system file.
+    std::optional<cstring> ifSystemFile(const IR::Node *node);
+    /// dump node IR tree up to depth - in the form of a comment
     void dump(unsigned depth, const IR::Node *node = nullptr, unsigned adjDepth = 0);
     unsigned curDepth() const;