Initial cut at an asm writer emitter. So far, this only handles emission of

instructions, and only instructions that take no operands at that!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15386 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 99 insertions, 3 deletions

diff --git a/utils/TableGen/AsmWriterEmitter.cpp b/utils/TableGen/AsmWriterEmitter.cpp
new file mode 100644
index 0000000000..b2cf1072b9
--- /dev/null
+++ b/utils/TableGen/AsmWriterEmitter.cpp
@@ -0,0 +1,48 @@
+//===- AsmWriterEmitter.cpp - Generate an assembly writer -----------------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This tablegen backend is emits an assembly printer for the current target.
+// Note that this is currently fairly skeletal, but will grow over time.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AsmWriterEmitter.h"
+#include "CodeGenTarget.h"
+#include <ostream>
+using namespace llvm;
+
+void AsmWriterEmitter::run(std::ostream &O) {
+  EmitSourceFileHeader("Assembly Writer Source Fragment", O);
+
+  CodeGenTarget Target;
+  O <<
+  "/// printInstruction - This method is automatically generated by tablegen\n"
+  "/// from the instruction set description.  This method returns true if the\n"
+  "/// machine instruction was sufficiently described to print it, otherwise\n"
+  "/// it returns false.\n"
+    "bool " << Target.getName()
+            << "AsmPrinter::printInstruction(const MachineInstr *MI) {\n";
+  O << "  switch (MI->getOpcode()) {\n"
+       "  default: return false;\n";
+
+  std::string Namespace = Target.inst_begin()->second.Namespace;
+
+  for (CodeGenTarget::inst_iterator I = Target.inst_begin(),
+         E = Target.inst_end(); I != E; ++I)
+    if (!I->second.AsmString.empty()) {
+      const std::string &AsmString = I->second.AsmString;
+      O << "  case " << Namespace << "::" << I->first << ": O << \""
+        << AsmString << "\" << '\\n'; break;\n";
+    }
+
+  O << "  }\n"
+       "  return true;\n"
+       "}\n";
+  EmitSourceFileTail(O);
+}
diff --git a/utils/TableGen/AsmWriterEmitter.h b/utils/TableGen/AsmWriterEmitter.h
new file mode 100644
index 0000000000..42d070ec75
--- /dev/null
+++ b/utils/TableGen/AsmWriterEmitter.h
@@ -0,0 +1,31 @@
+//===- AsmWriterEmitter.h - Generate an assembly writer ---------*- C++ -*-===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This tablegen backend is responsible for emitting an assembly printer for the
+// code generator.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ASMWRITER_EMITTER_H
+#define ASMWRITER_EMITTER_H
+
+#include "TableGenBackend.h"
+
+namespace llvm {
+
+  class AsmWriterEmitter : public TableGenBackend {
+    RecordKeeper &Records;
+  public:
+    AsmWriterEmitter(RecordKeeper &R) : Records(R) {}
+    
+    // run - Output the asmwriter, returning true on failure.
+    void run(std::ostream &o);
+  };
+}
+#endif
diff --git a/utils/TableGen/CodeGenTarget.cpp b/utils/TableGen/CodeGenTarget.cpp
index 026119d8d0..422e8d0b4f 100644
--- a/utils/TableGen/CodeGenTarget.cpp
+++ b/utils/TableGen/CodeGenTarget.cpp
@@ -122,14 +122,23 @@ CodeGenInstruction::CodeGenInstruction(Record *R) : TheDef(R) {
   Namespace = R->getValueAsString("Namespace");
   AsmString = R->getValueAsString("AsmString");
 
-  //TODO: Parse OperandList
-  
   isReturn     = R->getValueAsBit("isReturn");
   isBranch     = R->getValueAsBit("isBranch");
   isBarrier    = R->getValueAsBit("isBarrier");
   isCall       = R->getValueAsBit("isCall");
   isTwoAddress = R->getValueAsBit("isTwoAddress");
   isTerminator = R->getValueAsBit("isTerminator");
+
+
+  //TODO: Parse OperandList
+  try {
+    DagInit *DI = R->getValueAsDag("OperandList");
+
+    // Cannot handle instructions with operands yet.
+    if (DI->getNumArgs())
+      AsmString.clear();
+  } catch (...) {
+  }
 }
 
 
diff --git a/utils/TableGen/TableGen.cpp b/utils/TableGen/TableGen.cpp
index 7bd52b37cf..dc980a60a8 100644
--- a/utils/TableGen/TableGen.cpp
+++ b/utils/TableGen/TableGen.cpp
@@ -22,6 +22,7 @@
 #include "CodeEmitterGen.h"
 #include "RegisterInfoEmitter.h"
 #include "InstrInfoEmitter.h"
+#include "AsmWriterEmitter.h"
 #include "InstrSelectorEmitter.h"
 #include <algorithm>
 #include <cstdio>
@@ -32,7 +33,7 @@ enum ActionType {
   PrintRecords,
   GenEmitter,
   GenRegisterEnums, GenRegister, GenRegisterHeader,
-  GenInstrEnums, GenInstrs, GenInstrSelector,
+  GenInstrEnums, GenInstrs, GenAsmWriter, GenInstrSelector,
   PrintEnums,
   Parse
 };
@@ -54,6 +55,8 @@ namespace {
                                "Generate enum values for instructions"),
                     clEnumValN(GenInstrs, "gen-instr-desc",
                                "Generate instruction descriptions"),
+                    clEnumValN(GenAsmWriter, "gen-asm-writer",
+                               "Generate assembly writer"),
                     clEnumValN(GenInstrSelector, "gen-instr-selector",
                                "Generate an instruction selector"),
                     clEnumValN(PrintEnums, "print-enums",
@@ -454,6 +457,11 @@ int main(int argc, char **argv) {
     case GenInstrs:
       InstrInfoEmitter(Records).run(*Out);
       break;
+
+    case GenAsmWriter:
+      AsmWriterEmitter(Records).run(*Out);
+      break;
+
     case GenInstrSelector:
       InstrSelectorEmitter(Records).run(*Out);
       break;