[LLVM-Tablegen] Pretty Printing Arguments in LLVM Intrinsics

This patch adds LLVM infrastructure to support pretty printing arguments of the intrinsics. The motivation is to increase the readability of LLVM intrinsics and facilitate easy modifications and debugging of LLVM IR.
This adds a property ArgInfo<ArgIndex, "argName", "functionName"> to the intrinsic arguments that enables printing self-explanatory inline comment for the arguments.
The addition of pretty print support can provide a simple, low-overhead feature that enhances usability of LLVM intrinsics without disrupting existing workflows.
Link to the RFC:
https://discourse.llvm.org/t/rfc-pretty-printing-immediate-arguments-in-llvm-intrinsics/88536

Signed-off-by: Dharuni R Acharya <[email protected]>

Author: DharuniRAcharya

llvm/include/llvm/IR/Intrinsics.h

@@ -30,6 +30,8 @@ class LLVMContext;
 class Module;
 class AttributeList;
 class AttributeSet;
+class raw_ostream;
+class Constant;
 
 /// This namespace contains an enum with a value for every intrinsic/builtin
 /// function known by LLVM. The enum values are returned by
@@ -81,6 +83,9 @@ namespace Intrinsic {
   /// Returns true if the intrinsic can be overloaded.
   LLVM_ABI bool isOverloaded(ID id);
 
+  /// Returns true if the intrinsic has pretty printed immediate arguments.
+  LLVM_ABI bool hasPrettyPrintedArgs(ID id);
+
   /// isTargetIntrinsic - Returns true if IID is an intrinsic specific to a
   /// certain target. If it is a generic intrinsic false is returned.
   LLVM_ABI bool isTargetIntrinsic(ID IID);
@@ -284,6 +289,10 @@ namespace Intrinsic {
   /// N.
   LLVM_ABI Intrinsic::ID getDeinterleaveIntrinsicID(unsigned Factor);
 
+  /// Print the argument info for the arguments with ArgInfo.
+  LLVM_ABI void printImmArg(ID IID, unsigned ArgIdx, raw_ostream &OS,
+                            const Constant *ImmArgVal);
+
   } // namespace Intrinsic
 
   } // namespace llvm

llvm/include/llvm/IR/Intrinsics.td

@@ -87,6 +87,14 @@ class NoUndef<AttrIndex idx> : IntrinsicProperty {
   int ArgNo = idx.Value;
 }
 
+// ArgInfo - The specified argument has an argument name and an optional argument printing
+// function for diagnostic output.
+class ArgInfo<AttrIndex idx, string argname, string funcname = ""> : IntrinsicProperty {
+  int ArgNo = idx.Value;
+  string ArgName = argname;
+  string FunctionName = funcname;
+}
+
 // NonNull - The return value or specified argument is not null.
 class NonNull<AttrIndex idx> : IntrinsicProperty {
   int ArgNo = idx.Value;

llvm/include/llvm/IR/IntrinsicsNVVM.td

@@ -2887,7 +2887,14 @@ foreach sp = [0, 1] in {
         defvar nargs = !size(args);
         defvar scale_d_imm = ArgIndex<!sub(nargs, 1)>;
         defvar scale_d_imm_range = [ImmArg<scale_d_imm>, Range<scale_d_imm, 0, 16>];
-        defvar intrinsic_properties = !listconcat(
+
+        // Check if this is the specific llvm.nvvm.tcgen05.mma.tensor intrinsic.
+        defvar is_target_intrinsic = !and(!eq(sp, 0), 
+                                          !eq(space, "tensor"), 
+                                          !eq(scale_d, 0), 
+                                          !eq(ashift, 0));
+
+        defvar base_properties = !listconcat(
           mma.common_intr_props,
           !if(!eq(scale_d, 1), scale_d_imm_range, []),
           [Range<ArgIndex<nargs>, 0, !if(!eq(scale_d, 1), 2, 4)>, // kind

llvm/include/llvm/IR/NVVMIntrinsicUtils.h

@@ -18,8 +18,11 @@
 #include <stdint.h>
 
 #include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/APInt.h"
+#include "llvm/IR/Constants.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/IntrinsicsNVPTX.h"
+#include "llvm/Support/raw_ostream.h"
 
 namespace llvm {
 namespace nvvm {
@@ -659,6 +662,51 @@ inline APFloat::roundingMode GetFMARoundingMode(Intrinsic::ID IntrinsicID) {
   llvm_unreachable("Invalid FP instrinsic rounding mode for NVVM fma");
 }
 
+inline void printTcgen05MMAKind(raw_ostream &OS, const Constant *ImmArgVal) {
+  if (const ConstantInt *CI = dyn_cast<ConstantInt>(ImmArgVal)) {
+    uint64_t Val = CI->getZExtValue();
+    switch (static_cast<Tcgen05MMAKind>(Val)) {
+    case Tcgen05MMAKind::F16:
+      OS << "f16";
+      return;
+    case Tcgen05MMAKind::TF32:
+      OS << "tf32";
+      return;
+    case Tcgen05MMAKind::F8F6F4:
+      OS << "f8f6f4";
+      return;
+    case Tcgen05MMAKind::I8:
+      OS << "i8";
+      return;
+    }
+  }
+  llvm_unreachable(
+      "printTcgen05MMAKind called with invalid value for immediate argument");
+}
+
+inline void printTcgen05CollectorUsageOp(raw_ostream &OS,
+                                         const Constant *ImmArgVal) {
+  if (const ConstantInt *CI = dyn_cast<ConstantInt>(ImmArgVal)) {
+    uint64_t Val = CI->getZExtValue();
+    switch (static_cast<Tcgen05CollectorUsageOp>(Val)) {
+    case Tcgen05CollectorUsageOp::DISCARD:
+      OS << "discard";
+      return;
+    case Tcgen05CollectorUsageOp::LASTUSE:
+      OS << "lastuse";
+      return;
+    case Tcgen05CollectorUsageOp::FILL:
+      OS << "fill";
+      return;
+    case Tcgen05CollectorUsageOp::USE:
+      OS << "use";
+      return;
+    }
+  }
+  llvm_unreachable("printTcgen05CollectorUsageOp called with invalid value for "
+                   "immediate argument");
+}
+
 } // namespace nvvm
 } // namespace llvm
 #endif // LLVM_IR_NVVMINTRINSICUTILS_H

llvm/lib/IR/AsmWriter.cpp

@@ -53,6 +53,7 @@
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
@@ -4580,12 +4581,38 @@ void AssemblyWriter::printInstruction(const Instruction &I) {
     Out << ' ';
     writeOperand(Operand, false);
     Out << '(';
+    bool HasPrettyPrintedArgs =
+        isa<IntrinsicInst>(CI) &&
+        Intrinsic::hasPrettyPrintedArgs(CI->getIntrinsicID());
+
     ListSeparator LS;
-    for (unsigned op = 0, Eop = CI->arg_size(); op < Eop; ++op) {
-      Out << LS;
-      writeParamOperand(CI->getArgOperand(op), PAL.getParamAttrs(op));
-    }
+    if (HasPrettyPrintedArgs) {
+      Function *CalledFunc = CI->getCalledFunction();
+      auto PrintArgComment = [&](unsigned ArgNo) {
+        const Constant *ConstArg = dyn_cast<Constant>(CI->getArgOperand(ArgNo));
+        if (!ConstArg)
+          return;
+        std::string ArgComment;
+        raw_string_ostream ArgCommentStream(ArgComment);
+        Intrinsic::ID IID = CalledFunc->getIntrinsicID();
+        Intrinsic::printImmArg(IID, ArgNo, ArgCommentStream, ConstArg);
+        if (ArgComment.empty())
+          return;
+        Out << "/* " << ArgComment << " */ ";
+      };
 
+      for (unsigned ArgNo = 0, NumArgs = CI->arg_size(); ArgNo < NumArgs;
+           ++ArgNo) {
+        Out << LS;
+        PrintArgComment(ArgNo);
+        writeParamOperand(CI->getArgOperand(ArgNo), PAL.getParamAttrs(ArgNo));
+      }
+    } else {
+      for (unsigned op = 0, Eop = CI->arg_size(); op < Eop; ++op) {
+        Out << LS;
+        writeParamOperand(CI->getArgOperand(op), PAL.getParamAttrs(op));
+      }
+    }
     // Emit an ellipsis if this is a musttail call in a vararg function.  This
     // is only to aid readability, musttail calls forward varargs by default.
     if (CI->isMustTailCall() && CI->getParent() &&
@@ -5009,12 +5036,10 @@ void AssemblyWriter::printUseLists(const Function *F) {
 //===----------------------------------------------------------------------===//
 
 void Function::print(raw_ostream &ROS, AssemblyAnnotationWriter *AAW,
-                     bool ShouldPreserveUseListOrder,
-                     bool IsForDebug) const {
+                     bool ShouldPreserveUseListOrder, bool IsForDebug) const {
   SlotTracker SlotTable(this->getParent());
   formatted_raw_ostream OS(ROS);
-  AssemblyWriter W(OS, SlotTable, this->getParent(), AAW,
-                   IsForDebug,
+  AssemblyWriter W(OS, SlotTable, this->getParent(), AAW, IsForDebug,
                    ShouldPreserveUseListOrder);
   W.printFunction(this);
 }

llvm/lib/IR/Intrinsics.cpp

@@ -32,6 +32,7 @@
 #include "llvm/IR/IntrinsicsX86.h"
 #include "llvm/IR/IntrinsicsXCore.h"
 #include "llvm/IR/Module.h"
+#include "llvm/IR/NVVMIntrinsicUtils.h"
 #include "llvm/IR/Type.h"
 
 using namespace llvm;
@@ -601,6 +602,12 @@ bool Intrinsic::isOverloaded(ID id) {
 #undef GET_INTRINSIC_OVERLOAD_TABLE
 }
 
+bool Intrinsic::hasPrettyPrintedArgs(ID id){
+#define GET_INTRINSIC_PRETTY_PRINT_TABLE
+#include "llvm/IR/IntrinsicImpl.inc"
+#undef GET_INTRINSIC_PRETTY_PRINT_TABLE
+}
+
 /// Table of per-target intrinsic name tables.
 #define GET_INTRINSIC_TARGET_DATA
 #include "llvm/IR/IntrinsicImpl.inc"
@@ -1142,3 +1149,7 @@ Intrinsic::ID Intrinsic::getDeinterleaveIntrinsicID(unsigned Factor) {
   assert(Factor >= 2 && Factor <= 8 && "Unexpected factor");
   return InterleaveIntrinsics[Factor - 2].Deinterleave;
 }
+
+#define GET_INTRINSIC_PRETTY_PRINT_ARGUMENTS
+#include "llvm/IR/IntrinsicImpl.inc"
+#undef GET_INTRINSIC_PRETTY_PRINT_ARGUMENTS

llvm/test/CodeGen/NVPTX/tcgen05-mma-tensor-formatted.ll

@@ -0,0 +1,41 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
+; NOTE: This sample test demonstrates the pretty print feature for NVPTX intrinsics
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+
+target triple = "nvptx64-nvidia-cuda"
+
+define void @tcgen05_mma_fp16_cta1(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d) {
+  ; CHECK-LABEL: define void @tcgen05_mma_fp16_cta1(
+  ; CHECK: call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, /* kind=f16 */ i32 0, /* cta_group= */ i32 1, /* collector=discard */ i32 0)
+  call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, i32 0, i32 1, i32 0)
+
+  ; CHECK: call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, /* kind=f16 */ i32 0, /* cta_group= */ i32 1, /* collector=lastuse */ i32 1)
+  call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, i32 0, i32 1, i32 1)
+
+  ; CHECK: call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, /* kind=f16 */ i32 0, /* cta_group= */ i32 1, /* collector=fill */ i32 2)
+  call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, i32 0, i32 1, i32 2)
+
+  ; CHECK: call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, /* kind=f16 */ i32 0, /* cta_group= */ i32 1, /* collector=use */ i32 3)
+  call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, i32 0, i32 1, i32 3)
+
+  ret void
+}
+
+define void @tcgen05_mma_f8f6f4_cta2(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d) {
+  ; CHECK-LABEL: define void @tcgen05_mma_f8f6f4_cta2(
+  ; CHECK: call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, /* kind=f8f6f4 */ i32 2, /* cta_group= */ i32 2, /* collector=discard */ i32 0)
+  call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, i32 2, i32 2, i32 0)
+
+  ; CHECK: call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, /* kind=f8f6f4 */ i32 2, /* cta_group= */ i32 2, /* collector=lastuse */ i32 1)
+  call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, i32 2, i32 2, i32 1)
+
+  ; CHECK: call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, /* kind=f8f6f4 */ i32 2, /* cta_group= */ i32 2, /* collector=fill */ i32 2)
+  call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, i32 2, i32 2, i32 2)
+
+  ; CHECK: call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, /* kind=f8f6f4 */ i32 2, /* cta_group= */ i32 2, /* collector=use */ i32 3)
+  call void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6) %dtmem, ptr addrspace(6) %atensor, i64 %b, i32 %idesc, i1 %enable_inp_d, i32 2, i32 2, i32 3)
+
+  ret void
+}
+
+declare void @llvm.nvvm.tcgen05.mma.tensor(ptr addrspace(6), ptr addrspace(6), i64, i32, i1, i32, i32, i32)

llvm/test/TableGen/intrinsic-arginfo.td

@@ -0,0 +1,71 @@
+// RUN: llvm-tblgen -gen-intrinsic-impl -I %p/../../include %s | FileCheck %s
+
+// Test ArgInfo property for pretty-printing intrinsic arguments.
+// This test verifies that TableGen generates the correct pretty-printing code
+// for intrinsics that use the ArgInfo property.
+
+include "llvm/IR/Intrinsics.td"
+
+// Simple intrinsic with two arguments that have ArgInfo.
+def int_dummy_foo_bar : DefaultAttrsIntrinsic<
+    [llvm_i32_ty],
+    [llvm_i32_ty,      // data
+     llvm_i32_ty,      // mode
+     llvm_i32_ty],     // stride
+    [IntrNoMem,
+     ImmArg<ArgIndex<1>>,
+     ArgInfo<ArgIndex<1>, "mode", "printDummyMode">,
+     ArgInfo<ArgIndex<2>, "stride">]>;
+
+// A custom floating point add with rounding and sat mode.
+def int_my_fadd_f32 : DefaultAttrsIntrinsic<
+    [llvm_float_ty],
+    [llvm_float_ty,    // a
+     llvm_float_ty,    // b
+     llvm_i32_ty,      // rounding_mode
+     llvm_i1_ty],      // saturation_mode
+    [IntrNoMem,
+     ImmArg<ArgIndex<2>>,
+     ImmArg<ArgIndex<3>>,
+     ArgInfo<ArgIndex<2>, "rounding_mode", "printRoundingMode">,
+     ArgInfo<ArgIndex<3>, "saturation_mode">]>;
+
+// CHECK: #ifdef GET_INTRINSIC_PRETTY_PRINT_TABLE
+// CHECK-NEXT: static constexpr uint8_t PPTable[] = {
+
+// CHECK: #endif // GET_INTRINSIC_PRETTY_PRINT_TABLE
+
+// CHECK: #ifdef GET_INTRINSIC_PRETTY_PRINT_ARGUMENTS
+// CHECK: void Intrinsic::printImmArg(ID IID, unsigned ArgIdx, raw_ostream &OS, const Constant *ImmArgVal) {
+
+// CHECK: case dummy_foo_bar:
+// CHECK-NEXT: switch (ArgIdx) {
+
+// CHECK-NEXT: case 1:
+// CHECK-NEXT: OS << "mode=";
+// CHECK-NEXT: printDummyMode(OS, ImmArgVal);
+// CHECK-NEXT: return;
+
+// CHECK-NEXT: case 2:
+// CHECK-NEXT: OS << "stride=";
+// CHECK-NEXT: return;
+
+// CHECK-NEXT: }
+// CHECK-NEXT: break;
+
+// CHECK: case my_fadd_f32:
+// CHECK-NEXT: switch (ArgIdx) {
+
+// CHECK-NEXT: case 2:
+// CHECK-NEXT: OS << "rounding_mode=";
+// CHECK-NEXT: printRoundingMode(OS, ImmArgVal);
+// CHECK-NEXT: return;
+
+// CHECK-NEXT: case 3:
+// CHECK-NEXT: OS << "saturation_mode=";
+// CHECK-NEXT: return;
+
+// CHECK-NEXT: }
+// CHECK-NEXT: break;
+
+// CHECK: #endif // GET_INTRINSIC_PRETTY_PRINT_ARGUMENTS

llvm/utils/TableGen/Basic/CodeGenIntrinsics.cpp

@@ -447,6 +447,14 @@ void CodeGenIntrinsic::setProperty(const Record *R) {
     int64_t Lower = R->getValueAsInt("Lower");
     int64_t Upper = R->getValueAsInt("Upper");
     addArgAttribute(ArgNo, Range, Lower, Upper);
+  } else if (R->isSubClassOf("ArgInfo")) {
+    unsigned ArgNo = R->getValueAsInt("ArgNo");
+    if (ArgNo < 1)
+      PrintFatalError(R->getLoc(),
+                      "ArgInfo requires ArgNo >= 1 (0 is return value)");
+    StringRef ArgName = R->getValueAsString("ArgName");
+    StringRef FuncName = R->getValueAsString("FunctionName");
+    addPrettyPrintFunction(ArgNo - 1, ArgName, FuncName);
   } else {
     llvm_unreachable("Unknown property!");
   }
@@ -474,3 +482,18 @@ void CodeGenIntrinsic::addArgAttribute(unsigned Idx, ArgAttrKind AK, uint64_t V,
     ArgumentAttributes.resize(Idx + 1);
   ArgumentAttributes[Idx].emplace_back(AK, V, V2);
 }
+
+void CodeGenIntrinsic::addPrettyPrintFunction(unsigned ArgIdx,
+                                              StringRef ArgName,
+                                              StringRef FuncName) {
+  auto It = llvm::find_if(PrettyPrintFunctions, [ArgIdx](const auto &Info) {
+    return Info.ArgIdx == ArgIdx;
+  });
+  if (It != PrettyPrintFunctions.end()) {
+    PrintFatalError(TheDef->getLoc(), "ArgInfo for argument " + Twine(ArgIdx) +
+                                          " is already defined as '" +
+                                          It->FuncName + "'");
+    return;
+  }
+  PrettyPrintFunctions.emplace_back(ArgIdx, ArgName, FuncName);
+}

llvm/utils/TableGen/Basic/CodeGenIntrinsics.h

@@ -149,6 +149,22 @@ struct CodeGenIntrinsic {
   void addArgAttribute(unsigned Idx, ArgAttrKind AK, uint64_t V = 0,
                        uint64_t V2 = 0);
 
+  /// Structure to store pretty print and argument information.
+  struct PrettyPrintArgInfo {
+    unsigned ArgIdx;
+    StringRef ArgName;
+    StringRef FuncName;
+
+    PrettyPrintArgInfo(unsigned Idx, StringRef Name, StringRef Func)
+        : ArgIdx(Idx), ArgName(Name), FuncName(Func) {}
+  };
+
+  /// Vector that stores ArgInfo (ArgIndex, ArgName, FunctionName).
+  SmallVector<PrettyPrintArgInfo> PrettyPrintFunctions;
+
+  void addPrettyPrintFunction(unsigned ArgIdx, StringRef ArgName,
+                              StringRef FuncName);
+
   bool hasProperty(enum SDNP Prop) const { return Properties & (1 << Prop); }
 
   /// Goes through all IntrProperties that have IsDefault value set and sets