Add library functions instead of checking for file names.

p4lang · Apr 30, 2024 · 4986811 · 4986811
1 parent 54d0981
commit 4986811
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Showing 4 changed files with 32 additions and 9 deletions.
diff --git a/backends/ebpf/ebpfProgram.cpp b/backends/ebpf/ebpfProgram.cpp
@@ -197,15 +197,13 @@ void EBPFProgram::emitTypes(CodeBuilder *builder) {
             builder->newline();
         }
         if (const auto *method = d->to<IR::Method>()) {
-            if (method->srcInfo.isValid()) {
+            if (!method->srcInfo.isValid()) {
                 continue;
             }
             // Ignore methods originating from core.p4 and ubpf_model.p4 because they are already
             // defined.
-            // TODO: Is there a more portable way to do this? Currently we check for a specific
-            // filename as the source of a method.
-            auto sourceName = std::filesystem::path(method->srcInfo.getSourceFile().c_str());
-            if (sourceName.filename() == "core.p4" || sourceName.filename() == "ubpf_model.p4") {
+            // TODO: Maybe we should still generate declarations for these methods?
+            if (isLibraryMethod(method->controlPlaneName())) {
                 continue;
             }
             EBPFMethodDeclaration methodInstance(method);
@@ -348,4 +346,17 @@ void EBPFProgram::emitPipeline(CodeBuilder *builder) {
     }
 }
 
+bool EBPFProgram::isLibraryMethod(cstring methodName) {
+    static std::set<cstring> DEFAULT_METHODS = {"static_assert", "verify"};
+    if (DEFAULT_METHODS.find(methodName) != DEFAULT_METHODS.end() && options.target != "xdp") {
+        return true;
+    }
+
+    static std::set<cstring> XDP_METHODS = {
+        "ebpf_ipv4_checksum",    "csum_replace2",    "csum_replace4",
+        "BPF_PERF_EVENT_OUTPUT", "BPF_KTIME_GET_NS",
+    };
+    return XDP_METHODS.find(methodName) != XDP_METHODS.end();
+}
+
 }  // namespace EBPF
diff --git a/backends/ebpf/ebpfProgram.h b/backends/ebpf/ebpfProgram.h
@@ -95,6 +95,11 @@ class EBPFProgram : public EBPFObject {
     virtual void emitLocalVariables(CodeBuilder *builder);
     virtual void emitPipeline(CodeBuilder *builder);
 
+    /// Checks whether a method name is considered to be part of the standard library, e.g., defined
+    /// in core.p4 or ebpf_model.p4.
+    /// TODO: Should we also distinguish overloaded methods?
+    virtual bool isLibraryMethod(cstring methodName);
+
  public:
     virtual void emitCommonPreamble(CodeBuilder *builder);
     virtual void emitGeneratedComment(CodeBuilder *builder);

diff --git a/backends/ubpf/ubpfProgram.cpp b/backends/ubpf/ubpfProgram.cpp
@@ -175,10 +175,8 @@ void UBPFProgram::emitTypes(EBPF::CodeBuilder *builder) {
             }
             // Ignore methods originating from core.p4 and ubpf_model.p4 because they are already
             // defined.
-            // TODO: Is there a more portable way to do this? Currently we check for a specific
-            // filename as the source of a method.
-            auto sourceName = std::filesystem::path(method->srcInfo.getSourceFile().c_str());
-            if (sourceName.filename() == "core.p4" || sourceName.filename() == "ubpf_model.p4") {
+            // TODO: Maybe we should still generate declarations for these methods?
+            if (isLibraryMethod(method->controlPlaneName())) {
                 continue;
             }
             EBPF::EBPFMethodDeclaration methodInstance(method);

diff --git a/backends/ubpf/ubpfProgram.h b/backends/ubpf/ubpfProgram.h
@@ -73,6 +73,15 @@ class UBPFProgram : public EBPF::EBPFProgram {
     void emitMetadataInstance(EBPF::CodeBuilder *builder) const;
     void emitLocalVariables(EBPF::CodeBuilder *builder) override;
     void emitPipeline(EBPF::CodeBuilder *builder) override;
+
+    bool isLibraryMethod(cstring methodName) override {
+        static std::set<cstring> DEFAULT_METHODS = {
+            "mark_to_drop", "mark_to_pass",  "ubpf_time_get_ns", "truncate",
+            "hash",         "csum_replace2", "csum_replace4",
+        };
+        return DEFAULT_METHODS.find(methodName) != DEFAULT_METHODS.end() ||
+               EBPFProgram::isLibraryMethod(methodName);
+    }
 };
 
 }  // namespace UBPF