[LLVMdev] automatically generating intrinsic declarations

Dan Gohman djg at cray.com
Tue Feb 6 06:41:28 PST 2007


On Mon, Feb 05, 2007 at 12:28:56PM -0800, Chris Lattner wrote:
> On Mon, 5 Feb 2007, Dan Gohman wrote:
> 
> > LLVM knows what all the types of the intrinsic functions are; I thought, 
> > why are users (including llvm-gcc...) required to duplicate all this 
> > information in order to use them? I mean in order to call 
> > getOrInsertFunction to get declarations for them.
> 
> That is an excellent question!  :)  In the bad old days, we used to allow 
> intrinsics with slightly different types (e.g. http://llvm.org/PR1093). 
> Because of this, we didn't know what type to create them as.
> 
> Fortunately however, this misguided past is all behind us now, and there 
> is no longer a reason to not have this facility.

It appears there is at least one more. The llvm.gcroot intrinsic is documented
as having generic argument types.

> > So I wrote this patch, which allows all this code to be generated
> > automatically. Is this a good approach?
> 
> This looks great, but appears to be missing the API that wraps the 
> generated piece of Intrinsics.gen.  If you send it as well, I'd be happy 
> to commit it for you.  Is there also a piece that switches llvm-gcc over 
> to use this? :)

Attached is a patch that includes the API bits.

I also noticed that my earlier patch didn't handle pointer types, so I fixed
that, and in doing so I noticed that the types for va_start, va_end, va_copy,
and dbg.declare were apparently wrong, so I fixed those too.

However, gcroot does currently come out as void @llvm.gcroot(i8**, i8*).

Dan

-- 
Dan Gohman, Cray Inc. <djg at cray.com>
-------------- next part --------------
Index: include/llvm/Intrinsics.h
===================================================================
RCS file: /var/cvs/llvm/llvm/include/llvm/Intrinsics.h,v
retrieving revision 1.40
diff -u -r1.40 Intrinsics.h
--- include/llvm/Intrinsics.h
+++ include/llvm/Intrinsics.h
@@ -18,6 +18,9 @@
 
 namespace llvm {
 
+class Constant;
+class Module;
+
 /// Intrinsic Namespace - This namespace contains an enum with a value for
 /// every intrinsic/builtin function known by LLVM.  These enum values are
 /// returned by Function::getIntrinsicID().
@@ -36,6 +39,10 @@
   /// Intrinsic::getName(ID) - Return the LLVM name for an intrinsic, such as
   /// "llvm.ppc.altivec.lvx".
   const char *getName(ID id);
+  
+  /// Intrinsic::getDeclaration(M, ID) - Create or insert an LLVM Function
+  /// declaration for an intrinsic, and return it.
+  Constant *getDeclaration(Module *M, ID id);
 } // End Intrinsic namespace
 
 } // End llvm namespace
Index: include/llvm/Intrinsics.td
===================================================================
RCS file: /var/cvs/llvm/llvm/include/llvm/Intrinsics.td,v
retrieving revision 1.41
diff -u -r1.41 Intrinsics.td
--- include/llvm/Intrinsics.td
+++ include/llvm/Intrinsics.td
@@ -68,6 +68,15 @@
   LLVMType ElTy = elty;
 } 
 
+class LLVMPointerType<LLVMType elty>
+  : LLVMType<iPTR, "Type::PointerTyID">{
+  LLVMType ElTy = elty;
+} 
+
+class LLVMEmptyStructType
+  : LLVMType<OtherVT, "Type::StructTyID">{
+} 
+
 def llvm_void_ty       : LLVMType<isVoid, "Type::VoidTyID">;
 def llvm_bool_ty       : LLVMIntegerType<i1, 1>;
 def llvm_i8_ty         : LLVMIntegerType<i8 , 8>;
@@ -76,9 +85,10 @@
 def llvm_i64_ty        : LLVMIntegerType<i64, 64>;
 def llvm_float_ty      : LLVMType<f32, "Type::FloatTyID">;
 def llvm_double_ty     : LLVMType<f64, "Type::DoubleTyID">;
-def llvm_ptr_ty        : LLVMType<iPTR, "Type::PointerTyID">;     // i8*
-def llvm_ptrptr_ty     : LLVMType<iPTR, "Type::PointerTyID">;     // i8**
-def llvm_descriptor_ty : LLVMType<iPTR, "Type::PointerTyID">;     // global*
+def llvm_ptr_ty        : LLVMPointerType<llvm_i8_ty>;             // i8*
+def llvm_ptrptr_ty     : LLVMPointerType<llvm_ptr_ty>;            // i8**
+def llvm_empty_ty      : LLVMEmptyStructType;                     // { }
+def llvm_descriptor_ty : LLVMPointerType<llvm_empty_ty>;          // { }*
 
 def llvm_v16i8_ty      : LLVMPackedType<v16i8,16, llvm_i8_ty>;    // 16 x i8
 def llvm_v8i16_ty      : LLVMPackedType<v8i16, 8, llvm_i16_ty>;   //  8 x i16
@@ -121,10 +131,10 @@
 //===--------------- Variable Argument Handling Intrinsics ----------------===//
 //  
 
-def int_vastart : Intrinsic<[llvm_void_ty, llvm_ptrptr_ty], [], "llvm.va_start">;
-def int_vacopy  : Intrinsic<[llvm_void_ty, llvm_ptrptr_ty, llvm_ptrptr_ty], [],
+def int_vastart : Intrinsic<[llvm_void_ty, llvm_ptr_ty], [], "llvm.va_start">;
+def int_vacopy  : Intrinsic<[llvm_void_ty, llvm_ptr_ty, llvm_ptr_ty], [],
                             "llvm.va_copy">;
-def int_vaend   : Intrinsic<[llvm_void_ty, llvm_ptrptr_ty], [], "llvm.va_end">;
+def int_vaend   : Intrinsic<[llvm_void_ty, llvm_ptr_ty], [], "llvm.va_end">;
 
 //===------------------- Garbage Collection Intrinsics --------------------===//
 //  
@@ -214,7 +224,7 @@
 def int_dbg_region_start : Intrinsic<[llvm_void_ty, llvm_descriptor_ty]>;
 def int_dbg_region_end   : Intrinsic<[llvm_void_ty, llvm_descriptor_ty]>;
 def int_dbg_func_start   : Intrinsic<[llvm_void_ty, llvm_descriptor_ty]>;
-def int_dbg_declare      : Intrinsic<[llvm_void_ty, llvm_ptr_ty,
+def int_dbg_declare      : Intrinsic<[llvm_void_ty, llvm_descriptor_ty,
                                                     llvm_descriptor_ty]>;
 
 //===----------------------------------------------------------------------===//
Index: lib/VMCore/Function.cpp
===================================================================
RCS file: /var/cvs/llvm/llvm/lib/VMCore/Function.cpp,v
retrieving revision 1.111
diff -u -r1.111 Function.cpp
--- lib/VMCore/Function.cpp
+++ lib/VMCore/Function.cpp
@@ -183,6 +183,12 @@
   return Table[id];
 }
 
+Constant *Intrinsic::getDeclaration(Module *M, ID id) {
+#define GET_INTRINSIC_GENERATOR
+#include "llvm/Intrinsics.gen"
+#undef GET_INTRINSIC_GENERATOR
+}
+
 Value *IntrinsicInst::StripPointerCasts(Value *Ptr) {
   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr)) {
     if (CE->getOpcode() == Instruction::BitCast) {
Index: utils/TableGen/IntrinsicEmitter.cpp
===================================================================
RCS file: /var/cvs/llvm/llvm/utils/TableGen/IntrinsicEmitter.cpp,v
retrieving revision 1.22
diff -u -r1.22 IntrinsicEmitter.cpp
--- utils/TableGen/IntrinsicEmitter.cpp
+++ utils/TableGen/IntrinsicEmitter.cpp
@@ -38,6 +38,9 @@
   // Emit the intrinsic verifier.
   EmitVerifier(Ints, OS);
   
+  // Emit the intrinsic declaration generator.
+  EmitGenerator(Ints, OS);
+  
   // Emit mod/ref info for each function.
   EmitModRefInfo(Ints, OS);
   
@@ -121,6 +124,25 @@
   }
 }
 
+static void EmitTypeGenerate(std::ostream &OS, Record *ArgType) {
+  if (ArgType->isSubClassOf("LLVMIntegerType")) {
+    OS << "IntegerType::get(" << ArgType->getValueAsInt("Width") << ")";
+  } else if (ArgType->isSubClassOf("LLVMPackedType")) {
+    OS << "PackedType::get(";
+    EmitTypeGenerate(OS, ArgType->getValueAsDef("ElTy"));
+    OS << ", " << ArgType->getValueAsInt("NumElts") << ")";
+  } else if (ArgType->isSubClassOf("LLVMPointerType")) {
+    OS << "PointerType::get(";
+    EmitTypeGenerate(OS, ArgType->getValueAsDef("ElTy"));
+    OS << ")";
+  } else if (ArgType->isSubClassOf("LLVMEmptyStructType")) {
+    OS << "StructType::get(std::vector<const Type *>())";
+  } else {
+    OS << "Type::getPrimitiveType(";
+    OS << ArgType->getValueAsString("TypeVal") << ")";
+  }
+}
+
 /// RecordListComparator - Provide a determinstic comparator for lists of
 /// records.
 namespace {
@@ -176,6 +198,43 @@
   OS << "#endif\n\n";
 }
 
+void IntrinsicEmitter::EmitGenerator(const std::vector<CodeGenIntrinsic> &Ints, 
+                                     std::ostream &OS) {
+  OS << "// Code for generating Intrinsic function declarations.\n";
+  OS << "#ifdef GET_INTRINSIC_GENERATOR\n";
+  OS << "  switch (id) {\n";
+  OS << "  default: assert(0 && \"Invalid intrinsic!\");\n";
+  
+  // Similar to GET_INTRINSIC_VERIFIER, batch up cases that have identical
+  // types.
+  typedef std::map<std::vector<Record*>, std::vector<unsigned>, 
+    RecordListComparator> MapTy;
+  MapTy UniqueArgInfos;
+  
+  // Compute the unique argument type info.
+  for (unsigned i = 0, e = Ints.size(); i != e; ++i)
+    UniqueArgInfos[Ints[i].ArgTypeDefs].push_back(i);
+
+  // Loop through the array, emitting one generator for each batch.
+  for (MapTy::iterator I = UniqueArgInfos.begin(),
+       E = UniqueArgInfos.end(); I != E; ++I) {
+    for (unsigned i = 0, e = I->second.size(); i != e; ++i) {
+      OS << "  case Intrinsic::" << Ints[I->second[i]].EnumName << ":\t\t// "
+         << Ints[I->second[i]].Name << "\n";
+    }
+    
+    const std::vector<Record*> &ArgTypes = I->first;
+    OS << "    return M->getOrInsertFunction(Intrinsic::getName(id), ";
+    for (unsigned j = 0; j != ArgTypes.size(); ++j) {
+      EmitTypeGenerate(OS, ArgTypes[j]);
+      OS << ", ";
+    }
+    OS << "NULL);\n";
+  }
+  OS << "  }\n";
+  OS << "#endif\n\n";
+}
+
 void IntrinsicEmitter::EmitModRefInfo(const std::vector<CodeGenIntrinsic> &Ints,
                                       std::ostream &OS) {
   OS << "// BasicAliasAnalysis code.\n";
Index: utils/TableGen/IntrinsicEmitter.h
===================================================================
RCS file: /var/cvs/llvm/llvm/utils/TableGen/IntrinsicEmitter.h,v
retrieving revision 1.9
diff -u -r1.9 IntrinsicEmitter.h
--- utils/TableGen/IntrinsicEmitter.h
+++ utils/TableGen/IntrinsicEmitter.h
@@ -35,6 +35,8 @@
                                   std::ostream &OS);
     void EmitVerifier(const std::vector<CodeGenIntrinsic> &Ints, 
                       std::ostream &OS);
+    void EmitGenerator(const std::vector<CodeGenIntrinsic> &Ints, 
+                       std::ostream &OS);
     void EmitModRefInfo(const std::vector<CodeGenIntrinsic> &Ints, 
                         std::ostream &OS);
     void EmitNoMemoryInfo(const std::vector<CodeGenIntrinsic> &Ints, 


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