Support table.apply().miss (#2051)

* Support table.apply().miss * Convert table.apply().miss to not table.apply.hit()
p4lang · Nov 6, 2019 · bd0308a · bd0308a
1 parent df500ee
commit bd0308a
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Showing 31 changed files with 497 additions and 16 deletions.
diff --git a/backends/bmv2/psa_switch/midend.cpp b/backends/bmv2/psa_switch/midend.cpp
@@ -39,6 +39,7 @@ limitations under the License.
 #include "midend/local_copyprop.h"
 #include "midend/nestedStructs.h"
 #include "midend/removeLeftSlices.h"
+#include "midend/removeMiss.h"
 #include "midend/removeParameters.h"
 #include "midend/removeUnusedParameters.h"
 #include "midend/simplifyKey.h"
@@ -93,6 +94,7 @@ PsaSwitchMidEnd::PsaSwitchMidEnd(CompilerOptions& options, std::ostream* outStre
     if (BMV2::PsaSwitchContext::get().options().loadIRFromJson == false) {
         std::initializer_list<Visitor *> midendPasses = {
             options.ndebug ? new P4::RemoveAssertAssume(&refMap, &typeMap) : nullptr,
+            new P4::RemoveMiss(&refMap, &typeMap),
             new P4::EliminateNewtype(&refMap, &typeMap),
             new P4::EliminateSerEnums(&refMap, &typeMap),
             new P4::RemoveActionParameters(&refMap, &typeMap),

diff --git a/backends/bmv2/simple_switch/midend.cpp b/backends/bmv2/simple_switch/midend.cpp
@@ -40,6 +40,7 @@ limitations under the License.
 #include "midend/local_copyprop.h"
 #include "midend/nestedStructs.h"
 #include "midend/removeLeftSlices.h"
+#include "midend/removeMiss.h"
 #include "midend/removeParameters.h"
 #include "midend/removeUnusedParameters.h"
 #include "midend/simplifyKey.h"
@@ -69,6 +70,7 @@ SimpleSwitchMidEnd::SimpleSwitchMidEnd(CompilerOptions& options, std::ostream* o
         std::initializer_list<Visitor *> midendPasses = {
             options.ndebug ? new P4::RemoveAssertAssume(&refMap, &typeMap) : nullptr,
             new P4::CheckTableSize(),
+            new P4::RemoveMiss(&refMap, &typeMap),
             new P4::EliminateNewtype(&refMap, &typeMap),
             new P4::EliminateSerEnums(&refMap, &typeMap),
             new P4::RemoveActionParameters(&refMap, &typeMap),

diff --git a/backends/ebpf/midend.cpp b/backends/ebpf/midend.cpp
@@ -37,6 +37,7 @@ limitations under the License.
 #include "midend/noMatch.h"
 #include "midend/removeExits.h"
 #include "midend/removeLeftSlices.h"
+#include "midend/removeMiss.h"
 #include "midend/removeParameters.h"
 #include "midend/removeSelectBooleans.h"
 #include "midend/simplifyKey.h"
@@ -76,6 +77,7 @@ const IR::ToplevelBlock* MidEnd::run(EbpfOptions& options,
     if (options.loadIRFromJson == false) {
         std::initializer_list<Visitor *> midendPasses = {
             new P4::ConvertEnums(&refMap, &typeMap, new EnumOn32Bits()),
+            new P4::RemoveMiss(&refMap, &typeMap),
             new P4::ClearTypeMap(&typeMap),
             new P4::EliminateNewtype(&refMap, &typeMap),
             new P4::SimplifyControlFlow(&refMap, &typeMap),

diff --git a/backends/p4test/midend.cpp b/backends/p4test/midend.cpp
@@ -45,6 +45,7 @@ limitations under the License.
 #include "midend/parserUnroll.h"
 #include "midend/predication.h"
 #include "midend/removeExits.h"
+#include "midend/removeMiss.h"
 #include "midend/removeParameters.h"
 #include "midend/removeSelectBooleans.h"
 #include "midend/simplifyKey.h"
@@ -80,6 +81,7 @@ MidEnd::MidEnd(CompilerOptions& options) {
     // TODO: handle bit-slices as out arguments
     addPasses({
         options.ndebug ? new P4::RemoveAssertAssume(&refMap, &typeMap) : nullptr,
+        new P4::RemoveMiss(&refMap, &typeMap),
         new P4::EliminateNewtype(&refMap, &typeMap),
         new P4::EliminateSerEnums(&refMap, &typeMap),
         new P4::RemoveActionParameters(&refMap, &typeMap),

diff --git a/frontends/p4/def_use.cpp b/frontends/p4/def_use.cpp
@@ -527,6 +527,7 @@ bool ComputeWriteSet::preorder(const IR::Member* expression) {
     if (type->is<IR::Type_Method>())
         return false;
     if (TableApplySolver::isHit(expression, storageMap->refMap, storageMap->typeMap) ||
+        TableApplySolver::isMiss(expression, storageMap->refMap, storageMap->typeMap) ||
         TableApplySolver::isActionRun(expression, storageMap->refMap, storageMap->typeMap))
         return false;
     auto storage = getWrites(expression->expr);

diff --git a/frontends/p4/sideEffects.cpp b/frontends/p4/sideEffects.cpp
@@ -168,9 +168,10 @@ class DismantleExpression : public Transform {
             if (leftValue)
                 typeMap->setLeftValue(result->final);
 
-            // Special case for table.apply().hit, which is not dismantled by
+            // Special case for table.apply().hit/miss, which is not dismantled by
             // the MethodCallExpression.
-            if (TableApplySolver::isHit(expression, refMap, typeMap)) {
+            if (TableApplySolver::isHit(expression, refMap, typeMap) ||
+                TableApplySolver::isMiss(expression, refMap, typeMap)) {
                 BUG_CHECK(type->is<IR::Type_Boolean>(), "%1%: not boolean", type);
                 auto tmp = result->createTemporary(type);
                 auto path = new IR::PathExpression(IR::ID(tmp, nullptr));
@@ -479,7 +480,8 @@ class DismantleExpression : public Transform {
         if (auto mmbr = getParent<IR::Member>()) {
             auto tbl = TableApplySolver::isActionRun(mmbr, refMap, typeMap);
             auto tbl1 = TableApplySolver::isHit(mmbr, refMap, typeMap);
-            tbl_apply = tbl != nullptr || tbl1 != nullptr;
+            auto tbl2 = TableApplySolver::isMiss(mmbr, refMap, typeMap);
+            tbl_apply = tbl != nullptr || tbl1 != nullptr || tbl2 != nullptr;
         }
         // Simplified method call, with arguments substituted
         auto simplified = new IR::MethodCallExpression(

diff --git a/frontends/p4/tableApply.cpp b/frontends/p4/tableApply.cpp
@@ -41,6 +41,28 @@ TableApplySolver::isHit(const IR::Expression* expression,
     return am->object->to<IR::P4Table>();
 }
 
+const IR::P4Table*
+TableApplySolver::isMiss(const IR::Expression* expression,
+                         ReferenceMap* refMap,
+                         TypeMap* typeMap) {
+    if (!expression->is<IR::Member>())
+        return nullptr;
+    auto mem = expression->to<IR::Member>();
+    if (!mem->expr->is<IR::MethodCallExpression>())
+        return nullptr;
+    if (mem->member != IR::Type_Table::miss)
+        return nullptr;
+    auto mce = mem->expr->to<IR::MethodCallExpression>();
+    auto mi = P4::MethodInstance::resolve(mce, refMap, typeMap);
+    if (!mi->isApply())
+        return nullptr;
+
+    auto am = mi->to<P4::ApplyMethod>();
+    if (!am->object->is<IR::P4Table>())
+        return nullptr;
+    return am->object->to<IR::P4Table>();
+}
+
 const IR::P4Table*
 TableApplySolver::isActionRun(const IR::Expression* expression,
                               ReferenceMap* refMap,

diff --git a/frontends/p4/tableApply.h b/frontends/p4/tableApply.h
@@ -28,13 +28,16 @@ limitations under the License.
 namespace P4 {
 
 // These are used to figure out whether an expression has the form:
-// table.apply().hit
+// table.apply().hit,
+// table.apply().miss,
 // or
 // table.apply().action_run
 class TableApplySolver {
  public:
     static const IR::P4Table* isHit(const IR::Expression* expression,
                                     ReferenceMap* refMap, TypeMap* typeMap);
+    static const IR::P4Table* isMiss(const IR::Expression* expression,
+                                     ReferenceMap* refMap, TypeMap* typeMap);
     static const IR::P4Table* isActionRun(const IR::Expression* expression,
                                           ReferenceMap* refMap, TypeMap* typeMap);
 };

diff --git a/ir/ir.cpp b/ir/ir.cpp
@@ -180,8 +180,9 @@ P4Table::getApplyMethodType() const {
             actions);
     auto alv = actions->value->to<IR::ActionList>();
     auto hit = new IR::StructField(IR::Type_Table::hit, IR::Type_Boolean::get());
+    auto miss = new IR::StructField(IR::Type_Table::miss, IR::Type_Boolean::get());
     auto label = new IR::StructField(IR::Type_Table::action_run, new IR::Type_ActionEnum(alv));
-    auto rettype = new IR::Type_Struct(ID(name), { hit, label });
+    auto rettype = new IR::Type_Struct(ID(name), { hit, miss, label });
     auto applyMethod = new IR::Type_Method(rettype, new IR::ParameterList());
     return applyMethod;
 }

diff --git a/ir/type.cpp b/ir/type.cpp
@@ -32,6 +32,7 @@ const cstring IR::Type_StructLike::minSizeInBits = "minSizeInBits";
 const cstring IR::Type_StructLike::minSizeInBytes = "minSizeInBytes";
 
 const IR::ID IR::Type_Table::hit = ID("hit");
+const IR::ID IR::Type_Table::miss = ID("miss");
 const IR::ID IR::Type_Table::action_run = ID("action_run");
 
 const cstring IR::Annotation::nameAnnotation = "name";

diff --git a/ir/type.def b/ir/type.def
@@ -446,6 +446,7 @@ class Type_Table : Type, IApply {
     /// names for the fields of the struct returned
     /// by applying a table
     static const ID hit;
+    static const ID miss;
     static const ID action_run;
     const IR::Type* getP4Type() const override { return nullptr; }
     dbprint { out << table->name; }

diff --git a/midend/CMakeLists.txt b/midend/CMakeLists.txt
@@ -17,11 +17,12 @@ set (MIDEND_SRCS
   complexComparison.cpp
   convertEnums.cpp
   copyStructures.cpp
-  eliminateTuples.cpp
   eliminateNewtype.cpp
   eliminateSerEnums.cpp
+  eliminateTuples.cpp
   expandEmit.cpp
   expandLookahead.cpp
+  fillEnumMap.cpp
   flattenHeaders.cpp
   flattenInterfaceStructs.cpp
   interpreter.cpp
@@ -31,8 +32,10 @@ set (MIDEND_SRCS
   orderArguments.cpp
   parserUnroll.cpp
   predication.cpp
+  removeAssertAssume.cpp
   removeExits.cpp
   removeLeftSlices.cpp
+  removeMiss.cpp
   removeParameters.cpp
   removeSelectBooleans.cpp
   removeUnusedParameters.cpp
@@ -43,8 +46,6 @@ set (MIDEND_SRCS
   singleArgumentSelect.cpp
   tableHit.cpp
   validateProperties.cpp
-  fillEnumMap.cpp
-  removeAssertAssume.cpp
   )
 
 set (MIDEND_HDRS
@@ -54,14 +55,15 @@ set (MIDEND_HDRS
   complexComparison.h
   convertEnums.h
   copyStructures.h
-  eliminateTuples.h
   eliminateNewtype.h
   eliminateSerEnums.h
+  eliminateTuples.h
   expandEmit.h
   expandLookahead.h
   expr_uses.h
-  flattenInterfaceStructs.h
+  fillEnumMap.h
   flattenHeaders.h
+  flattenInterfaceStructs.h
   has_side_effects.h
   interpreter.h
   local_copyprop.h
@@ -71,8 +73,10 @@ set (MIDEND_HDRS
   orderArguments.h
   parserUnroll.h
   predication.h
+  removeAssertAssume.h
   removeExits.h
   removeLeftSlices.h
+  removeMiss.h
   removeParameters.h
   removeSelectBooleans.h
   removeUnusedParameters.h
@@ -83,8 +87,6 @@ set (MIDEND_HDRS
   singleArgumentSelect.h
   tableHit.h
   validateProperties.h
-  fillEnumMap.h
-  removeAssertAssume.h
   )
 
 add_cpplint_files (${CMAKE_CURRENT_SOURCE_DIR} "${MIDEND_SRCS};${MIDEND_HDRS}")

diff --git a/midend/removeMiss.cpp b/midend/removeMiss.cpp
@@ -0,0 +1,29 @@
+/*
+Copyright 2019 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.
+*/
+
+#include "removeMiss.h"
+#include "frontends/p4/tableApply.h"
+
+namespace P4 {
+
+const IR::Node* DoRemoveMiss::preorder(IR::Member* expression) {
+    if (!TableApplySolver::isMiss(expression, refMap, typeMap))
+        return expression;
+    auto hit = new IR::Member(expression->expr, IR::Type_Table::hit);
+    return new IR::LNot(hit);
+}
+
+}  // namespace P4
diff --git a/midend/removeMiss.h b/midend/removeMiss.h
@@ -0,0 +1,54 @@
+/*
+Copyright 2019 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.
+*/
+
+#ifndef _MIDEND_REMOVEMISS_H_
+#define _MIDEND_REMOVEMISS_H_
+
+#include "ir/ir.h"
+#include "frontends/p4/typeChecking/typeChecker.h"
+#include "frontends/common/resolveReferences/referenceMap.h"
+#include "frontends/p4/typeMap.h"
+
+namespace P4 {
+
+/**
+ *  This visitor converts table.apply().miss into !table.apply().hit.
+ */
+class DoRemoveMiss : public Transform {
+    ReferenceMap* refMap;
+    TypeMap* typeMap;
+ public:
+    DoRemoveMiss(ReferenceMap* refMap, TypeMap* typeMap) :
+            refMap(refMap), typeMap(typeMap)
+    { visitDagOnce = false; CHECK_NULL(typeMap); setName("DoRemoveMiss"); }
+    const IR::Node* preorder(IR::Member* expression) override;
+};
+
+class RemoveMiss : public PassManager {
+ public:
+    RemoveMiss(ReferenceMap* refMap, TypeMap* typeMap,
+               TypeChecking* typeChecking = nullptr) {
+        if (!typeChecking)
+            typeChecking = new TypeChecking(refMap, typeMap);
+        passes.push_back(typeChecking);
+        passes.push_back(new DoRemoveMiss(refMap, typeMap));
+        setName("RemoveMiss");
+    }
+};
+
+}  // namespace P4
+
+#endif /* _MIDEND_REMOVEMISS_H_ */
diff --git a/midend/tableHit.cpp b/midend/tableHit.cpp
@@ -21,16 +21,25 @@ namespace P4 {
 
 const IR::Node* DoTableHit::postorder(IR::AssignmentStatement* statement) {
     LOG3("Visiting " << getOriginal());
-    if (!TableApplySolver::isHit(statement->right, refMap, typeMap))
+    auto right = statement->right;
+    bool negated = false;
+    if (auto neg = right->to<IR::LNot>()) {
+        // We handle !hit, which may have been created by the removal of miss
+        negated = true;
+        right = neg->expr;
+    }
+
+    if (!TableApplySolver::isHit(right, refMap, typeMap))
         return statement;
 
     auto tstat = new IR::AssignmentStatement(
         statement->left->clone(), new IR::BoolLiteral(true));
     auto fstat = new IR::AssignmentStatement(
         statement->left->clone(), new IR::BoolLiteral(false));
-    auto ifStatement = new IR::IfStatement(
-        statement->right, tstat, fstat);
-    return ifStatement;
+    if (negated)
+        return new IR::IfStatement(right, fstat, tstat);
+    else
+        return new IR::IfStatement(right, tstat, fstat);
 }
 
 }  // namespace P4
diff --git a/testdata/p4_16_samples/hit-expr.p4 → testdata/p4_16_samples/hit-expr-bmv2.p4 b/testdata/p4_16_samples/hit-expr.p4 → testdata/p4_16_samples/hit-expr-bmv2.p4
diff --git a/testdata/p4_16_samples/issue2044-bmv2.p4 b/testdata/p4_16_samples/issue2044-bmv2.p4
@@ -0,0 +1,42 @@
+#include <core.p4>
+#include <v1model.p4>
+
+header hdr {
+    bit<32> b;
+}
+
+struct Headers {
+    hdr h;
+}
+
+struct Meta {}
+
+parser p(packet_in b, out Headers h, inout Meta m, inout standard_metadata_t sm) {
+    state start {
+        transition accept;
+    }
+}
+
+control vrfy(inout Headers h, inout Meta m) { apply {} }
+control update(inout Headers h, inout Meta m) { apply {} }
+
+control egress(inout Headers h, inout Meta m, inout standard_metadata_t sm) { apply {} }
+
+control deparser(packet_out b, in Headers h) {
+    apply { b.emit(h); }
+}
+
+control ingress(inout Headers h, inout Meta m, inout standard_metadata_t sm) {
+    table t {
+        key = { h.h.b : exact; }
+        actions = { NoAction; }
+        default_action = NoAction;
+    }
+    apply {
+        if (t.apply().miss) {
+            h.h.setInvalid();
+        }
+    }
+}
+
+V1Switch(p(), vrfy(), ingress(), egress(), update(), deparser()) main;
diff --git a/...a/p4_16_samples_outputs/hit-expr-first.p4 → ...16_samples_outputs/hit-expr-bmv2-first.p4 b/...a/p4_16_samples_outputs/hit-expr-first.p4 → ...16_samples_outputs/hit-expr-bmv2-first.p4
diff --git a/...4_16_samples_outputs/hit-expr-frontend.p4 → ...samples_outputs/hit-expr-bmv2-frontend.p4 b/...4_16_samples_outputs/hit-expr-frontend.p4 → ...samples_outputs/hit-expr-bmv2-frontend.p4
diff --git a/.../p4_16_samples_outputs/hit-expr-midend.p4 → ...6_samples_outputs/hit-expr-bmv2-midend.p4 b/.../p4_16_samples_outputs/hit-expr-midend.p4 → ...6_samples_outputs/hit-expr-bmv2-midend.p4
diff --git a/testdata/p4_16_samples_outputs/hit-expr.p4 → ...ta/p4_16_samples_outputs/hit-expr-bmv2.p4 b/testdata/p4_16_samples_outputs/hit-expr.p4 → ...ta/p4_16_samples_outputs/hit-expr-bmv2.p4
diff --git a/.../p4_16_samples_outputs/hit-expr.p4-stderr → ...6_samples_outputs/hit-expr-bmv2.p4-stderr b/.../p4_16_samples_outputs/hit-expr.p4-stderr → ...6_samples_outputs/hit-expr-bmv2.p4-stderr
diff --git a/...6_samples_outputs/hit-expr.p4.entries.txt → ...ples_outputs/hit-expr-bmv2.p4.entries.txt b/...6_samples_outputs/hit-expr.p4.entries.txt → ...ples_outputs/hit-expr-bmv2.p4.entries.txt
diff --git a/...16_samples_outputs/hit-expr.p4.p4info.txt → ...mples_outputs/hit-expr-bmv2.p4.p4info.txt b/...16_samples_outputs/hit-expr.p4.p4info.txt → ...mples_outputs/hit-expr-bmv2.p4.p4info.txt