[llvm] [IR] Allow MDString in operand bundles (PR #110805)
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Wed Oct 2 01:53:50 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-ir
Author: Serge Pavlov (spavloff)
<details>
<summary>Changes</summary>
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.
---
Full diff: https://github.com/llvm/llvm-project/pull/110805.diff
8 Files Affected:
- (modified) llvm/docs/LangRef.rst (+3-3)
- (modified) llvm/docs/ReleaseNotes.md (+2)
- (modified) llvm/include/llvm/AsmParser/LLParser.h (+1)
- (modified) llvm/include/llvm/Bitcode/LLVMBitCodes.h (+3)
- (modified) llvm/lib/AsmParser/LLParser.cpp (+14)
- (modified) llvm/lib/Bitcode/Reader/BitcodeReader.cpp (+19-2)
- (modified) llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (+16-1)
- (modified) llvm/test/Bitcode/operand-bundles.ll (+24)
``````````diff
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 3f39d58b322a4f..8f5cad8a530053 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -2665,8 +2665,8 @@ 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.
@@ -2674,7 +2674,7 @@ 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 f44d636a203374..de836b7a50b893 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -86,6 +86,8 @@ 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/AsmParser/LLParser.h b/llvm/include/llvm/AsmParser/LLParser.h
index 9576b935198dd4..ccb5c4450b76c7 100644
--- a/llvm/include/llvm/AsmParser/LLParser.h
+++ b/llvm/include/llvm/AsmParser/LLParser.h
@@ -66,6 +66,7 @@ namespace llvm {
t_EmptyArray, // No value: []
t_Constant, // Value in ConstantVal.
t_ConstantSplat, // Value in ConstantVal.
+ t_MDString, // Value in StrVal.
t_InlineAsm, // Value in FTy/StrVal/StrVal2/UIntVal.
t_ConstantStruct, // Value in ConstantStructElts.
t_PackedConstantStruct // Value in ConstantStructElts.
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 d84521d2e6e10d..5553850d31f5a8 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -3941,6 +3941,15 @@ bool LLParser::parseValID(ValID &ID, PerFunctionState *PFS, Type *ExpectedTy) {
ID.Kind = ValID::t_Constant;
return false;
+ case lltok::exclaim: {
+ Lex.Lex();
+ ID.StrVal = Lex.getStrVal();
+ if (parseToken(lltok::StringConstant, "expected string"))
+ return true;
+ ID.Kind = ValID::t_MDString;
+ return false;
+ }
+
case lltok::kw_asm: {
// ValID ::= 'asm' SideEffect? AlignStack? IntelDialect? STRINGCONSTANT ','
// STRINGCONSTANT
@@ -6216,6 +6225,11 @@ bool LLParser::convertValIDToValue(Type *Ty, ValID &ID, Value *&V,
V = ConstantVector::getSplat(cast<VectorType>(Ty)->getElementCount(),
ID.ConstantVal);
return false;
+ case ValID::t_MDString:
+ if (!Ty->isMetadataTy())
+ return error(ID.Loc, "invalid type for metadata string");
+ V = MetadataAsValue::get(Context, MDString::get(Context, ID.StrVal));
+ return false;
case ValID::t_ConstantStruct:
case ValID::t_PackedConstantStruct:
if (StructType *ST = dyn_cast<StructType>(Ty)) {
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/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
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/110805
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