AArch64: TableGenerate system instruction operands.

The way the named arguments for various system instructions are handled at the
moment has a few problems:

  - Large-scale duplication between AArch64BaseInfo.h and AArch64BaseInfo.cpp
  - That weird Mapping class that I have no idea what I was on when I thought
    it was a good idea.
  - Searches are performed linearly through the entire list.
  - We print absolutely all registers in upper-case, even though some are
    canonically mixed case (SPSel for example).
  - The ARM ARM specifies sysregs in terms of 5 fields, but those are relegated
    to comments in our implementation, with a slightly opaque hex value
    indicating the canonical encoding LLVM will use.

This adds a new TableGen backend to produce efficiently searchable tables, and
switches AArch64 over to using that infrastructure.

llvm-svn: 274576

4 files changed, 329 insertions, 1 deletions

diff --git a/llvm/utils/TableGen/CMakeLists.txt b/llvm/utils/TableGen/CMakeLists.txt
index eef1540424d..e8fe30f5ac7 100644
--- a/llvm/utils/TableGen/CMakeLists.txt
+++ b/llvm/utils/TableGen/CMakeLists.txt
@@ -27,6 +27,7 @@ add_tablegen(llvm-tblgen LLVM
   OptParserEmitter.cpp
   PseudoLoweringEmitter.cpp
   RegisterInfoEmitter.cpp
+  SearchableTableEmitter.cpp
   SubtargetEmitter.cpp
   TableGen.cpp
   X86DisassemblerTables.cpp
diff --git a/llvm/utils/TableGen/SearchableTableEmitter.cpp b/llvm/utils/TableGen/SearchableTableEmitter.cpp
new file mode 100644
index 00000000000..1b0e67f835f
--- /dev/null
+++ b/llvm/utils/TableGen/SearchableTableEmitter.cpp
@@ -0,0 +1,320 @@
+//===- SearchableTableEmitter.cpp - Generate efficiently searchable tables -==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This tablegen backend emits a generic array initialized by specified fields,
+// together with companion index tables and lookup functions (binary search,
+// currently).
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/TableGen/Error.h"
+#include "llvm/TableGen/Record.h"
+#include <algorithm>
+#include <sstream>
+#include <string>
+#include <vector>
+using namespace llvm;
+
+#define DEBUG_TYPE "searchable-table-emitter"
+
+namespace {
+
+class SearchableTableEmitter {
+  RecordKeeper &Records;
+
+public:
+  SearchableTableEmitter(RecordKeeper &R) : Records(R) {}
+
+  void run(raw_ostream &OS);
+
+private:
+  typedef std::pair<Init *, int> SearchTableEntry;
+
+  int getAsInt(BitsInit *B) {
+    return cast<IntInit>(B->convertInitializerTo(IntRecTy::get()))->getValue();
+  }
+  int getInt(Record *R, StringRef Field) {
+    return getAsInt(R->getValueAsBitsInit(Field));
+  }
+
+  std::string primaryRepresentation(Init *I) {
+    if (StringInit *SI = dyn_cast<StringInit>(I))
+      return SI->getAsString();
+    else if (BitsInit *BI = dyn_cast<BitsInit>(I))
+      return "0x" + utohexstr(getAsInt(BI));
+    else if (BitInit *BI = dyn_cast<BitInit>(I))
+      return BI->getValue() ? "true" : "false";
+    else if (CodeInit *CI = dyn_cast<CodeInit>(I)) {
+      return CI->getValue();
+    }
+    PrintFatalError(SMLoc(),
+                    "invalid field type, expected: string, bits, bit or code");
+  }
+
+  std::string searchRepresentation(Init *I) {
+    std::string PrimaryRep = primaryRepresentation(I);
+    if (!isa<StringInit>(I))
+      return PrimaryRep;
+    return StringRef(PrimaryRep).upper();
+  }
+
+  std::string searchableFieldType(Init *I) {
+    if (isa<StringInit>(I))
+      return "const char *";
+    else if (BitsInit *BI = dyn_cast<BitsInit>(I)) {
+      unsigned NumBits = BI->getNumBits();
+      if (NumBits <= 8)
+        NumBits = 8;
+      else if (NumBits <= 16)
+        NumBits = 16;
+      else if (NumBits <= 32)
+        NumBits = 32;
+      else if (NumBits <= 64)
+        NumBits = 64;
+      else
+        PrintFatalError(SMLoc(), "bitfield too large to search");
+      return "uint" + utostr(NumBits) + "_t";
+    }
+    PrintFatalError(SMLoc(), "Unknown type to search by");
+  }
+
+  void emitMapping(Record *MappingDesc, raw_ostream &OS);
+  void emitMappingEnum(std::vector<Record *> &Items, Record *InstanceClass,
+                       raw_ostream &OS);
+  void
+  emitPrimaryTable(StringRef Name, std::vector<std::string> &FieldNames,
+                   std::vector<std::string> &SearchFieldNames,
+                   std::vector<std::vector<SearchTableEntry>> &SearchTables,
+                   std::vector<Record *> &Items, raw_ostream &OS);
+  void emitSearchTable(StringRef Name, StringRef Field,
+                       std::vector<SearchTableEntry> &SearchTable,
+                       raw_ostream &OS);
+  void emitLookupDeclaration(StringRef Name, StringRef Field, Init *I,
+                             raw_ostream &OS);
+  void emitLookupFunction(StringRef Name, StringRef Field, Init *I,
+                          raw_ostream &OS);
+};
+
+} // End anonymous namespace.
+
+/// Emit an enum providing symbolic access to some preferred field from
+/// C++.
+void SearchableTableEmitter::emitMappingEnum(std::vector<Record *> &Items,
+                                             Record *InstanceClass,
+                                             raw_ostream &OS) {
+  std::string EnumNameField = InstanceClass->getValueAsString("EnumNameField");
+  std::string EnumValueField;
+  if (!InstanceClass->isValueUnset("EnumValueField"))
+    EnumValueField = InstanceClass->getValueAsString("EnumValueField");
+
+  OS << "enum " << InstanceClass->getName() << "Values {\n";
+  for (auto Item : Items) {
+    OS << "  " << Item->getValueAsString(EnumNameField);
+    if (EnumValueField != StringRef())
+      OS << " = " << getInt(Item, EnumValueField);
+    OS << ",\n";
+  }
+  OS << "};\n\n";
+}
+
+void SearchableTableEmitter::emitPrimaryTable(
+    StringRef Name, std::vector<std::string> &FieldNames,
+    std::vector<std::string> &SearchFieldNames,
+    std::vector<std::vector<SearchTableEntry>> &SearchTables,
+    std::vector<Record *> &Items, raw_ostream &OS) {
+  OS << "const " << Name << " " << Name << "sList[] = {\n";
+
+  for (auto Item : Items) {
+    OS << "  { ";
+    for (unsigned i = 0; i < FieldNames.size(); ++i) {
+      OS << primaryRepresentation(Item->getValueInit(FieldNames[i]));
+      if (i != FieldNames.size() - 1)
+        OS << ", ";
+    }
+    OS << "},\n";
+  }
+  OS << "};\n\n";
+}
+
+void SearchableTableEmitter::emitSearchTable(
+    StringRef Name, StringRef Field, std::vector<SearchTableEntry> &SearchTable,
+    raw_ostream &OS) {
+  OS << "const std::pair<" << searchableFieldType(SearchTable[0].first)
+     << ", int> " << Name << "sBy" << Field << "[] = {\n";
+
+  if (isa<BitsInit>(SearchTable[0].first)) {
+    std::stable_sort(SearchTable.begin(), SearchTable.end(),
+                     [this](const SearchTableEntry &LHS,
+                            const SearchTableEntry &RHS) {
+                       return getAsInt(cast<BitsInit>(LHS.first)) <
+                              getAsInt(cast<BitsInit>(RHS.first));
+                     });
+  } else {
+    std::stable_sort(SearchTable.begin(), SearchTable.end(),
+                     [this](const SearchTableEntry &LHS,
+                            const SearchTableEntry &RHS) {
+                       return searchRepresentation(LHS.first) <
+                              searchRepresentation(RHS.first);
+                     });
+  }
+
+  for (auto Entry : SearchTable) {
+    OS << "  { " << searchRepresentation(Entry.first) << ", " << Entry.second
+       << " },\n";
+  }
+  OS << "};\n\n";
+}
+
+void SearchableTableEmitter::emitLookupFunction(StringRef Name, StringRef Field,
+                                                Init *I, raw_ostream &OS) {
+  bool IsIntegral = isa<BitsInit>(I);
+  std::string FieldType = searchableFieldType(I);
+  std::string PairType = "std::pair<" + FieldType + ", int>";
+
+  // const SysRegs *lookupSysRegByName(const char *Name) {
+  OS << "const " << Name << " *"
+     << "lookup" << Name << "By" << Field;
+  OS << "(" << (IsIntegral ? FieldType : "StringRef") << " " << Field
+     << ") {\n";
+
+  if (IsIntegral) {
+    OS << "  auto CanonicalVal = " << Field << ";\n";
+    OS << " " << PairType << " Val = {CanonicalVal, 0};\n";
+  } else {
+    // Make sure the result is null terminated because it's going via "char *".
+    OS << "  std::string CanonicalVal = " << Field << ".upper();\n";
+    OS << "  " << PairType << " Val = {CanonicalVal.data(), 0};\n";
+  }
+
+  OS << "  ArrayRef<" << PairType << "> Table(" << Name << "sBy" << Field
+     << ");\n";
+  OS << "  auto Idx = std::lower_bound(Table.begin(), Table.end(), Val";
+
+  if (IsIntegral)
+    OS << ");\n";
+  else {
+    OS << ",\n                              ";
+    OS << "[](const " << PairType << " &LHS, const " << PairType
+       << " &RHS) {\n";
+    OS << "    return StringRef(LHS.first) < StringRef(RHS.first);\n";
+    OS << "  });\n\n";
+  }
+
+  OS << "  if (Idx == Table.end() || CanonicalVal != Idx->first)\n";
+  OS << "    return nullptr;\n";
+
+  OS << "  return &" << Name << "sList[Idx->second];\n";
+  OS << "}\n\n";
+}
+
+void SearchableTableEmitter::emitLookupDeclaration(StringRef Name,
+                                                   StringRef Field, Init *I,
+                                                   raw_ostream &OS) {
+  bool IsIntegral = isa<BitsInit>(I);
+  std::string FieldType = searchableFieldType(I);
+  OS << "const " << Name << " *"
+     << "lookup" << Name << "By" << Field;
+  OS << "(" << (IsIntegral ? FieldType : "StringRef") << " " << Field
+     << ");\n\n";
+}
+
+void SearchableTableEmitter::emitMapping(Record *InstanceClass,
+                                         raw_ostream &OS) {
+  std::string TableName = InstanceClass->getName();
+  std::vector<Record *> Items = Records.getAllDerivedDefinitions(TableName);
+
+  // Gather all the records we're going to need for this particular mapping.
+  std::vector<std::vector<SearchTableEntry>> SearchTables;
+  std::vector<std::string> SearchFieldNames;
+
+  std::vector<std::string> FieldNames;
+  for (const RecordVal &Field : InstanceClass->getValues()) {
+    std::string FieldName = Field.getName();
+
+    // Skip uninteresting fields: either built-in, special to us, or injected
+    // template parameters (if they contain a ':').
+    if (FieldName.find(':') != std::string::npos || FieldName == "NAME" ||
+        FieldName == "SearchableFields" || FieldName == "EnumNameField" ||
+        FieldName == "EnumValueField")
+      continue;
+
+    FieldNames.push_back(FieldName);
+  }
+
+  for (auto *Field : *InstanceClass->getValueAsListInit("SearchableFields")) {
+    SearchTables.emplace_back();
+    SearchFieldNames.push_back(Field->getAsUnquotedString());
+  }
+
+  int Idx = 0;
+  for (Record *Item : Items) {
+    for (unsigned i = 0; i < SearchFieldNames.size(); ++i) {
+      Init *SearchVal = Item->getValueInit(SearchFieldNames[i]);
+      SearchTables[i].emplace_back(SearchVal, Idx);
+    }
+    ++Idx;
+  }
+
+  OS << "#ifdef GET_" << StringRef(TableName).upper() << "_DECL\n";
+  OS << "#undef GET_" << StringRef(TableName).upper() << "_DECL\n";
+
+  // Next emit the enum containing the top-level names for use in C++ code if
+  // requested
+  if (!InstanceClass->isValueUnset("EnumNameField")) {
+    emitMappingEnum(Items, InstanceClass, OS);
+  }
+
+  // And the declarations for the functions that will perform lookup.
+  for (unsigned i = 0; i < SearchFieldNames.size(); ++i)
+    emitLookupDeclaration(TableName, SearchFieldNames[i],
+                          SearchTables[i][0].first, OS);
+
+  OS << "#endif\n\n";
+
+  OS << "#ifdef GET_" << StringRef(TableName).upper() << "_IMPL\n";
+  OS << "#undef GET_" << StringRef(TableName).upper() << "_IMPL\n";
+
+  // The primary data table contains all the fields defined for this map.
+  emitPrimaryTable(TableName, FieldNames, SearchFieldNames, SearchTables, Items,
+                   OS);
+
+  // Indexes are sorted "{ Thing, PrimaryIdx }" arrays, so that a binary
+  // search can be performed by "Thing".
+  for (unsigned i = 0; i < SearchTables.size(); ++i) {
+    emitSearchTable(TableName, SearchFieldNames[i], SearchTables[i], OS);
+    emitLookupFunction(TableName, SearchFieldNames[i], SearchTables[i][0].first,
+                       OS);
+  }
+
+  OS << "#endif\n";
+}
+
+void SearchableTableEmitter::run(raw_ostream &OS) {
+  // Tables are defined to be the direct descendents of "SearchableEntry".
+  Record *SearchableTable = Records.getClass("SearchableTable");
+  for (auto &NameRec : Records.getClasses()) {
+    Record *Class = NameRec.second.get();
+    if (Class->getSuperClasses().size() != 1 ||
+        !Class->isSubClassOf(SearchableTable))
+      continue;
+    emitMapping(Class, OS);
+  }
+}
+
+namespace llvm {
+
+void EmitSearchableTables(RecordKeeper &RK, raw_ostream &OS) {
+  SearchableTableEmitter(RK).run(OS);
+}
+
+} // End llvm namespace.
diff --git a/llvm/utils/TableGen/TableGen.cpp b/llvm/utils/TableGen/TableGen.cpp
index cf751235535..24dbe5d3a28 100644
--- a/llvm/utils/TableGen/TableGen.cpp
+++ b/llvm/utils/TableGen/TableGen.cpp
@@ -43,7 +43,8 @@ enum ActionType {
   PrintSets,
   GenOptParserDefs,
   GenCTags,
-  GenAttributes
+  GenAttributes,
+  GenSearchableTables,
 };
 
 namespace {
@@ -89,6 +90,8 @@ namespace {
                                "Generate ctags-compatible index"),
                     clEnumValN(GenAttributes, "gen-attrs",
                                "Generate attributes"),
+                    clEnumValN(GenSearchableTables, "gen-searchable-tables",
+                               "Generate generic binary-searchable table"),
                     clEnumValEnd));
 
   cl::opt<std::string>
@@ -172,6 +175,9 @@ bool LLVMTableGenMain(raw_ostream &OS, RecordKeeper &Records) {
   case GenAttributes:
     EmitAttributes(Records, OS);
     break;
+  case GenSearchableTables:
+    EmitSearchableTables(Records, OS);
+    break;
   }
 
   return false;
diff --git a/llvm/utils/TableGen/TableGenBackends.h b/llvm/utils/TableGen/TableGenBackends.h
index d9dd3d15769..51e017fe659 100644
--- a/llvm/utils/TableGen/TableGenBackends.h
+++ b/llvm/utils/TableGen/TableGenBackends.h
@@ -79,6 +79,7 @@ void EmitMapTable(RecordKeeper &RK, raw_ostream &OS);
 void EmitOptParser(RecordKeeper &RK, raw_ostream &OS);
 void EmitCTags(RecordKeeper &RK, raw_ostream &OS);
 void EmitAttributes(RecordKeeper &RK, raw_ostream &OS);
+void EmitSearchableTables(RecordKeeper &RK, raw_ostream &OS);
 
 } // End llvm namespace