[llvm] 15de239 - [IR] Allow MDString in operand bundles (#110805)

via llvm-commits llvm-commits at lists.llvm.org
Thu Oct 10 22:09:14 PDT 2024


Author: Serge Pavlov
Date: 2024-10-11T12:09:10+07:00
New Revision: 15de239406bfc0a1dfbd0640490c4bd5d1e0ac33

URL: https://github.com/llvm/llvm-project/commit/15de239406bfc0a1dfbd0640490c4bd5d1e0ac33
DIFF: https://github.com/llvm/llvm-project/commit/15de239406bfc0a1dfbd0640490c4bd5d1e0ac33.diff

LOG: [IR] Allow MDString in operand bundles (#110805)

This change implements support of metadata strings in operand bundle
values. It makes possible calls like:

    call void @some_func(i32 %x) [ "foo"(i32 42, metadata !"abc") ]

It requires some extension of the bitcode serialization. As SSA values
and metadata are stored in different tables, there must be a way to
distinguish them during deserialization. It is implemented by putting a
special marker before the metadata index. The marker cannot be treated
as a reference to any SSA value, so it unambiguously identifies
metadata. It allows extending the bitcode serialization without breaking
compatibility.

Metadata as operand bundle values are intended to be used in
floating-point function calls. They would represent the same information
as now is passed by the constrained intrinsic arguments.

Added: 
    

Modified: 
    llvm/docs/LangRef.rst
    llvm/docs/ReleaseNotes.md
    llvm/include/llvm/Bitcode/LLVMBitCodes.h
    llvm/lib/AsmParser/LLParser.cpp
    llvm/lib/Bitcode/Reader/BitcodeReader.cpp
    llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
    llvm/test/Bitcode/compatibility.ll
    llvm/test/Bitcode/operand-bundles.ll

Removed: 
    


################################################################################
diff  --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 0c7279de06cd68..a330b804930326 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -2666,8 +2666,8 @@ are grouped into a single :ref:`attribute group <attrgrp>`.
 Operand Bundles
 ---------------
 
-Operand bundles are tagged sets of SSA values that can be associated
-with certain LLVM instructions (currently only ``call`` s and
+Operand bundles are tagged sets of SSA values or metadata strings that can be
+associated with certain LLVM instructions (currently only ``call`` s and
 ``invoke`` s).  In a way they are like metadata, but dropping them is
 incorrect and will change program semantics.
 
@@ -2675,7 +2675,7 @@ Syntax::
 
     operand bundle set ::= '[' operand bundle (, operand bundle )* ']'
     operand bundle ::= tag '(' [ bundle operand ] (, bundle operand )* ')'
-    bundle operand ::= SSA value
+    bundle operand ::= SSA value | metadata string
     tag ::= string constant
 
 Operand bundles are **not** part of a function's signature, and a

diff  --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index 8ac5900a7e532e..dcdd7a25c7fbee 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -88,6 +88,8 @@ Changes to the LLVM IR
   * `llvm.nvvm.ptr.shared.to.gen`
   * `llvm.nvvm.ptr.constant.to.gen`
   * `llvm.nvvm.ptr.local.to.gen`
+  
+* Operand bundle values can now be metadata strings.
 
 Changes to LLVM infrastructure
 ------------------------------

diff  --git a/llvm/include/llvm/Bitcode/LLVMBitCodes.h b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
index cbd92fd52fc75a..ba2efee9414218 100644
--- a/llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -529,6 +529,9 @@ enum PossiblyExactOperatorOptionalFlags { PEO_EXACT = 0 };
 /// PossiblyDisjointInst's SubclassOptionalData contents.
 enum PossiblyDisjointInstOptionalFlags { PDI_DISJOINT = 0 };
 
+/// Mark to distinguish metadata from value in an operator bundle.
+enum MetadataOperandBundleValueMarker { OB_METADATA = 0x80000000 };
+
 /// GetElementPtrOptionalFlags - Flags for serializing
 /// GEPOperator's SubclassOptionalData contents.
 enum GetElementPtrOptionalFlags {

diff  --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 9f2ef2e6a9311e..c3b4a8235ce637 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -3202,8 +3202,14 @@ bool LLParser::parseOptionalOperandBundles(
 
       Type *Ty = nullptr;
       Value *Input = nullptr;
-      if (parseType(Ty) || parseValue(Ty, Input, PFS))
+      if (parseType(Ty))
         return true;
+      if (Ty->isMetadataTy()) {
+        if (parseMetadataAsValue(Input, PFS))
+          return true;
+      } else if (parseValue(Ty, Input, PFS)) {
+        return true;
+      }
       Inputs.push_back(Input);
     }
 

diff  --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 6f997510b03609..8ee93253bc2447 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -792,6 +792,24 @@ class BitcodeReader : public BitcodeReaderBase, public GVMaterializer {
     return ResVal == nullptr;
   }
 
+  bool getValueOrMetadata(const SmallVectorImpl<uint64_t> &Record,
+                          unsigned &Slot, unsigned InstNum, Value *&ResVal,
+                          BasicBlock *ConstExprInsertBB) {
+    if (Slot == Record.size())
+      return true;
+    unsigned ValID = Record[Slot++];
+    if (ValID != bitc::OB_METADATA) {
+      unsigned TypeId;
+      return getValueTypePair(Record, --Slot, InstNum, ResVal, TypeId,
+                              ConstExprInsertBB);
+    }
+    if (Slot == Record.size())
+      return true;
+    unsigned ValNo = InstNum - (unsigned)Record[Slot++];
+    ResVal = MetadataAsValue::get(Context, getFnMetadataByID(ValNo));
+    return false;
+  }
+
   /// Read a value out of the specified record from slot 'Slot'. Increment Slot
   /// past the number of slots used by the value in the record. Return true if
   /// there is an error.
@@ -6767,8 +6785,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
       unsigned OpNum = 1;
       while (OpNum != Record.size()) {
         Value *Op;
-        unsigned OpTypeID;
-        if (getValueTypePair(Record, OpNum, NextValueNo, Op, OpTypeID, CurBB))
+        if (getValueOrMetadata(Record, OpNum, NextValueNo, Op, CurBB))
           return error("Invalid record");
         Inputs.push_back(Op);
       }

diff  --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index d9086bfebbd2a9..bec0caef58afa8 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -395,6 +395,8 @@ class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
   void writeModuleConstants();
   bool pushValueAndType(const Value *V, unsigned InstID,
                         SmallVectorImpl<unsigned> &Vals);
+  bool pushValueOrMetadata(const Value *V, unsigned InstID,
+                           SmallVectorImpl<unsigned> &Vals);
   void writeOperandBundles(const CallBase &CB, unsigned InstID);
   void pushValue(const Value *V, unsigned InstID,
                  SmallVectorImpl<unsigned> &Vals);
@@ -2931,6 +2933,19 @@ bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
   return false;
 }
 
+bool ModuleBitcodeWriter::pushValueOrMetadata(const Value *V, unsigned InstID,
+                                              SmallVectorImpl<unsigned> &Vals) {
+  bool IsMetadata = V->getType()->isMetadataTy();
+  if (IsMetadata) {
+    Vals.push_back(bitc::OB_METADATA);
+    Metadata *MD = cast<MetadataAsValue>(V)->getMetadata();
+    unsigned ValID = VE.getMetadataID(MD);
+    Vals.push_back(InstID - ValID);
+    return false;
+  }
+  return pushValueAndType(V, InstID, Vals);
+}
+
 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
                                               unsigned InstID) {
   SmallVector<unsigned, 64> Record;
@@ -2941,7 +2956,7 @@ void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
 
     for (auto &Input : Bundle.Inputs)
-      pushValueAndType(Input, InstID, Record);
+      pushValueOrMetadata(Input, InstID, Record);
 
     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
     Record.clear();

diff  --git a/llvm/test/Bitcode/compatibility.ll b/llvm/test/Bitcode/compatibility.ll
index a1b2370a87b821..280c3a99d7535f 100644
--- a/llvm/test/Bitcode/compatibility.ll
+++ b/llvm/test/Bitcode/compatibility.ll
@@ -1327,6 +1327,14 @@ continue:
   ret i32 0
 }
 
+declare void @instructions.bundles.callee(i32)
+define void @instructions.bundles.metadata(i32 %x) {
+entry:
+  call void @instructions.bundles.callee(i32 %x) [ "foo"(i32 42, metadata !"abc"), "bar"(metadata !"abcde", metadata !"qwerty") ]
+; CHECK: call void @instructions.bundles.callee(i32 %x) [ "foo"(i32 42, metadata !"abc"), "bar"(metadata !"abcde", metadata !"qwerty") ]
+  ret void
+}
+
 ; Instructions -- Unary Operations
 define void @instructions.unops(double %op1) {
   fneg double %op1

diff  --git a/llvm/test/Bitcode/operand-bundles.ll b/llvm/test/Bitcode/operand-bundles.ll
index ab28cffd84aa29..a8e086f784c6cf 100644
--- a/llvm/test/Bitcode/operand-bundles.ll
+++ b/llvm/test/Bitcode/operand-bundles.ll
@@ -56,6 +56,13 @@ define void @f4(i32* %ptr) {
   ret void
 }
 
+define void @f5(i32 %x) {
+entry:
+  call void @callee1(i32 10, i32 %x) [ "foo"(i32 42, metadata !"abc"), "bar"(metadata !"abcde", metadata !"qwerty") ]
+; CHECK: call void @callee1(i32 10, i32 %x) [ "foo"(i32 42, metadata !"abc"), "bar"(metadata !"abcde", metadata !"qwerty") ]
+  ret void
+}
+
 ; Invoke versions of the above tests:
 
 
@@ -150,3 +157,20 @@ exception:
 normal:
   ret void
 }
+
+define void @g5(ptr %ptr) personality i8 3 {
+entry:
+  %l = load i32, ptr %ptr, align 4
+  %x = add i32 42, 1
+  invoke void @callee1(i32 10, i32 %x) [ "foo"(i32 42, metadata !"abc"), "bar"(metadata !"abcde", metadata !"qwerty") ]
+          to label %normal unwind label %exception
+; CHECK:   invoke void @callee1(i32 10, i32 %x) [ "foo"(i32 42, metadata !"abc"), "bar"(metadata !"abcde", metadata !"qwerty") ]
+
+exception:                                        ; preds = %entry
+  %cleanup = landingpad i8
+          cleanup
+  br label %normal
+
+normal:                                           ; preds = %exception, %entry
+  ret void
+}


        


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