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llvm-project/llvm/utils/TableGen/AsmMatcherEmitter.cpp

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//===- AsmMatcherEmitter.cpp - Generate an assembly matcher ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This tablegen backend emits a target specifier matcher for converting parsed
// assembly operands in the MCInst structures.
//
// The input to the target specific matcher is a list of literal tokens and
// operands. The target specific parser should generally eliminate any syntax
// which is not relevant for matching; for example, comma tokens should have
// already been consumed and eliminated by the parser. Most instructions will
// end up with a single literal token (the instruction name) and some number of
// operands.
//
// Some example inputs, for X86:
// 'addl' (immediate ...) (register ...)
// 'add' (immediate ...) (memory ...)
// 'call' '*' %epc
//
// The assembly matcher is responsible for converting this input into a precise
// machine instruction (i.e., an instruction with a well defined encoding). This
// mapping has several properties which complicate matching:
//
// - It may be ambiguous; many architectures can legally encode particular
// variants of an instruction in different ways (for example, using a smaller
// encoding for small immediates). Such ambiguities should never be
// arbitrarily resolved by the assembler, the assembler is always responsible
// for choosing the "best" available instruction.
//
// - It may depend on the subtarget or the assembler context. Instructions
// which are invalid for the current mode, but otherwise unambiguous (e.g.,
// an SSE instruction in a file being assembled for i486) should be accepted
// and rejected by the assembler front end. However, if the proper encoding
// for an instruction is dependent on the assembler context then the matcher
// is responsible for selecting the correct machine instruction for the
// current mode.
//
// The core matching algorithm attempts to exploit the regularity in most
// instruction sets to quickly determine the set of possibly matching
// instructions, and the simplify the generated code. Additionally, this helps
// to ensure that the ambiguities are intentionally resolved by the user.
//
// The matching is divided into two distinct phases:
//
// 1. Classification: Each operand is mapped to the unique set which (a)
// contains it, and (b) is the largest such subset for which a single
// instruction could match all members.
//
// For register classes, we can generate these subgroups automatically. For
// arbitrary operands, we expect the user to define the classes and their
// relations to one another (for example, 8-bit signed immediates as a
// subset of 32-bit immediates).
//
// By partitioning the operands in this way, we guarantee that for any
// tuple of classes, any single instruction must match either all or none
// of the sets of operands which could classify to that tuple.
//
// In addition, the subset relation amongst classes induces a partial order
// on such tuples, which we use to resolve ambiguities.
//
// FIXME: What do we do if a crazy case shows up where this is the wrong
// resolution?
//
// 2. The input can now be treated as a tuple of classes (static tokens are
// simple singleton sets). Each such tuple should generally map to a single
// instruction (we currently ignore cases where this isn't true, whee!!!),
// which we can emit a simple matcher for.
//
//===----------------------------------------------------------------------===//
#include "AsmMatcherEmitter.h"
#include "CodeGenTarget.h"
#include "Record.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include <list>
#include <map>
#include <set>
using namespace llvm;
namespace {
static cl::opt<std::string>
MatchPrefix("match-prefix", cl::init(""),
cl::desc("Only match instructions with the given prefix"));
}
/// FlattenVariants - Flatten an .td file assembly string by selecting the
/// variant at index \arg N.
static std::string FlattenVariants(const std::string &AsmString,
unsigned N) {
StringRef Cur = AsmString;
std::string Res = "";
for (;;) {
// Find the start of the next variant string.
size_t VariantsStart = 0;
for (size_t e = Cur.size(); VariantsStart != e; ++VariantsStart)
if (Cur[VariantsStart] == '{' &&
(VariantsStart == 0 || (Cur[VariantsStart-1] != '$' &&
Cur[VariantsStart-1] != '\\')))
break;
// Add the prefix to the result.
Res += Cur.slice(0, VariantsStart);
if (VariantsStart == Cur.size())
break;
++VariantsStart; // Skip the '{'.
// Scan to the end of the variants string.
size_t VariantsEnd = VariantsStart;
unsigned NestedBraces = 1;
for (size_t e = Cur.size(); VariantsEnd != e; ++VariantsEnd) {
if (Cur[VariantsEnd] == '}' && Cur[VariantsEnd-1] != '\\') {
if (--NestedBraces == 0)
break;
} else if (Cur[VariantsEnd] == '{')
++NestedBraces;
}
// Select the Nth variant (or empty).
StringRef Selection = Cur.slice(VariantsStart, VariantsEnd);
for (unsigned i = 0; i != N; ++i)
Selection = Selection.split('|').second;
Res += Selection.split('|').first;
assert(VariantsEnd != Cur.size() &&
"Unterminated variants in assembly string!");
Cur = Cur.substr(VariantsEnd + 1);
}
return Res;
}
/// TokenizeAsmString - Tokenize a simplified assembly string.
static void TokenizeAsmString(const StringRef &AsmString,
SmallVectorImpl<StringRef> &Tokens) {
unsigned Prev = 0;
bool InTok = true;
for (unsigned i = 0, e = AsmString.size(); i != e; ++i) {
switch (AsmString[i]) {
case '[':
case ']':
case '*':
case '!':
case ' ':
case '\t':
case ',':
if (InTok) {
Tokens.push_back(AsmString.slice(Prev, i));
InTok = false;
}
if (!isspace(AsmString[i]) && AsmString[i] != ',')
Tokens.push_back(AsmString.substr(i, 1));
Prev = i + 1;
break;
case '\\':
if (InTok) {
Tokens.push_back(AsmString.slice(Prev, i));
InTok = false;
}
++i;
assert(i != AsmString.size() && "Invalid quoted character");
Tokens.push_back(AsmString.substr(i, 1));
Prev = i + 1;
break;
case '$': {
// If this isn't "${", treat like a normal token.
if (i + 1 == AsmString.size() || AsmString[i + 1] != '{') {
if (InTok) {
Tokens.push_back(AsmString.slice(Prev, i));
InTok = false;
}
Prev = i;
break;
}
if (InTok) {
Tokens.push_back(AsmString.slice(Prev, i));
InTok = false;
}
StringRef::iterator End =
std::find(AsmString.begin() + i, AsmString.end(), '}');
assert(End != AsmString.end() && "Missing brace in operand reference!");
size_t EndPos = End - AsmString.begin();
Tokens.push_back(AsmString.slice(i, EndPos+1));
Prev = EndPos + 1;
i = EndPos;
break;
}
default:
InTok = true;
}
}
if (InTok && Prev != AsmString.size())
Tokens.push_back(AsmString.substr(Prev));
}
static bool IsAssemblerInstruction(const StringRef &Name,
const CodeGenInstruction &CGI,
const SmallVectorImpl<StringRef> &Tokens) {
// Ignore psuedo ops.
//
// FIXME: This is a hack.
if (const RecordVal *Form = CGI.TheDef->getValue("Form"))
if (Form->getValue()->getAsString() == "Pseudo")
return false;
// Ignore "PHI" node.
//
// FIXME: This is also a hack.
if (Name == "PHI")
return false;
// Ignore instructions with no .s string.
//
// FIXME: What are these?
if (CGI.AsmString.empty())
return false;
// FIXME: Hack; ignore any instructions with a newline in them.
if (std::find(CGI.AsmString.begin(),
CGI.AsmString.end(), '\n') != CGI.AsmString.end())
return false;
// Ignore instructions with attributes, these are always fake instructions for
// simplifying codegen.
//
// FIXME: Is this true?
//
// Also, we ignore instructions which reference the operand multiple times;
// this implies a constraint we would not currently honor. These are
// currently always fake instructions for simplifying codegen.
//
// FIXME: Encode this assumption in the .td, so we can error out here.
std::set<std::string> OperandNames;
for (unsigned i = 1, e = Tokens.size(); i < e; ++i) {
if (Tokens[i][0] == '$' &&
std::find(Tokens[i].begin(),
Tokens[i].end(), ':') != Tokens[i].end()) {
DEBUG({
errs() << "warning: '" << Name << "': "
<< "ignoring instruction; operand with attribute '"
<< Tokens[i] << "', \n";
});
return false;
}
if (Tokens[i][0] == '$' && !OperandNames.insert(Tokens[i]).second) {
DEBUG({
errs() << "warning: '" << Name << "': "
<< "ignoring instruction; tied operand '"
<< Tokens[i] << "'\n";
});
return false;
}
}
return true;
}
namespace {
/// ClassInfo - Helper class for storing the information about a particular
/// class of operands which can be matched.
struct ClassInfo {
enum ClassInfoKind {
Invalid = 0, ///< Invalid kind, for use as a sentinel value.
Token, ///< The class for a particular token.
Register, ///< A register class.
UserClass0 ///< The (first) user defined class, subsequent user defined
/// classes are UserClass0+1, and so on.
};
/// Kind - The class kind, which is either a predefined kind, or (UserClass0 +
/// N) for the Nth user defined class.
unsigned Kind;
/// SuperClassKind - The super class kind for user classes.
unsigned SuperClassKind;
/// SuperClass - The super class, or 0.
ClassInfo *SuperClass;
/// Name - The full class name, suitable for use in an enum.
std::string Name;
/// ClassName - The unadorned generic name for this class (e.g., Token).
std::string ClassName;
/// ValueName - The name of the value this class represents; for a token this
/// is the literal token string, for an operand it is the TableGen class (or
/// empty if this is a derived class).
std::string ValueName;
/// PredicateMethod - The name of the operand method to test whether the
/// operand matches this class; this is not valid for Token kinds.
std::string PredicateMethod;
/// RenderMethod - The name of the operand method to add this operand to an
/// MCInst; this is not valid for Token kinds.
std::string RenderMethod;
/// isUserClass() - Check if this is a user defined class.
bool isUserClass() const {
return Kind >= UserClass0;
}
/// getRootClass - Return the root class of this one.
const ClassInfo *getRootClass() const {
const ClassInfo *CI = this;
while (CI->SuperClass)
CI = CI->SuperClass;
return CI;
}
/// operator< - Compare two classes.
bool operator<(const ClassInfo &RHS) const {
// Incompatible kinds are comparable for classes in disjoint hierarchies.
if (Kind != RHS.Kind && getRootClass() != RHS.getRootClass())
return Kind < RHS.Kind;
switch (Kind) {
case Invalid:
assert(0 && "Invalid kind!");
case Token:
// Tokens are comparable by value.
//
// FIXME: Compare by enum value.
return ValueName < RHS.ValueName;
default:
// This class preceeds the RHS if the RHS is a super class.
for (ClassInfo *Parent = SuperClass; Parent; Parent = Parent->SuperClass)
if (Parent == &RHS)
return true;
return false;
}
}
};
/// InstructionInfo - Helper class for storing the necessary information for an
/// instruction which is capable of being matched.
struct InstructionInfo {
struct Operand {
/// The unique class instance this operand should match.
ClassInfo *Class;
/// The original operand this corresponds to, if any.
const CodeGenInstruction::OperandInfo *OperandInfo;
};
/// InstrName - The target name for this instruction.
std::string InstrName;
/// Instr - The instruction this matches.
const CodeGenInstruction *Instr;
/// AsmString - The assembly string for this instruction (with variants
/// removed).
std::string AsmString;
/// Tokens - The tokenized assembly pattern that this instruction matches.
SmallVector<StringRef, 4> Tokens;
/// Operands - The operands that this instruction matches.
SmallVector<Operand, 4> Operands;
/// ConversionFnKind - The enum value which is passed to the generated
/// ConvertToMCInst to convert parsed operands into an MCInst for this
/// function.
std::string ConversionFnKind;
/// operator< - Compare two instructions.
bool operator<(const InstructionInfo &RHS) const {
if (Operands.size() != RHS.Operands.size())
return Operands.size() < RHS.Operands.size();
for (unsigned i = 0, e = Operands.size(); i != e; ++i)
if (*Operands[i].Class < *RHS.Operands[i].Class)
return true;
return false;
}
/// CouldMatchAmiguouslyWith - Check whether this instruction could
/// ambiguously match the same set of operands as \arg RHS (without being a
/// strictly superior match).
bool CouldMatchAmiguouslyWith(const InstructionInfo &RHS) {
// The number of operands is unambiguous.
if (Operands.size() != RHS.Operands.size())
return false;
// Tokens and operand kinds are unambiguous (assuming a correct target
// specific parser).
for (unsigned i = 0, e = Operands.size(); i != e; ++i)
if (Operands[i].Class->Kind != RHS.Operands[i].Class->Kind ||
Operands[i].Class->Kind == ClassInfo::Token)
if (*Operands[i].Class < *RHS.Operands[i].Class ||
*RHS.Operands[i].Class < *Operands[i].Class)
return false;
// Otherwise, this operand could commute if all operands are equivalent, or
// there is a pair of operands that compare less than and a pair that
// compare greater than.
bool HasLT = false, HasGT = false;
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
if (*Operands[i].Class < *RHS.Operands[i].Class)
HasLT = true;
if (*RHS.Operands[i].Class < *Operands[i].Class)
HasGT = true;
}
return !(HasLT ^ HasGT);
}
public:
void dump();
};
class AsmMatcherInfo {
public:
/// The classes which are needed for matching.
std::vector<ClassInfo*> Classes;
/// The information on the instruction to match.
std::vector<InstructionInfo*> Instructions;
private:
/// Map of token to class information which has already been constructed.
std::map<std::string, ClassInfo*> TokenClasses;
/// Map of operand name to class information which has already been
/// constructed.
std::map<std::string, ClassInfo*> OperandClasses;
/// Map of user class names to kind value.
std::map<std::string, unsigned> UserClasses;
private:
/// getTokenClass - Lookup or create the class for the given token.
ClassInfo *getTokenClass(const StringRef &Token);
/// getUserClassKind - Lookup or create the kind value for the given class
/// name.
unsigned getUserClassKind(const StringRef &Name);
/// getOperandClass - Lookup or create the class for the given operand.
ClassInfo *getOperandClass(const StringRef &Token,
const CodeGenInstruction::OperandInfo &OI);
public:
/// BuildInfo - Construct the various tables used during matching.
void BuildInfo(CodeGenTarget &Target);
};
}
void InstructionInfo::dump() {
errs() << InstrName << " -- " << "flattened:\"" << AsmString << '\"'
<< ", tokens:[";
for (unsigned i = 0, e = Tokens.size(); i != e; ++i) {
errs() << Tokens[i];
if (i + 1 != e)
errs() << ", ";
}
errs() << "]\n";
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
Operand &Op = Operands[i];
errs() << " op[" << i << "] = " << Op.Class->ClassName << " - ";
if (Op.Class->Kind == ClassInfo::Token) {
errs() << '\"' << Tokens[i] << "\"\n";
continue;
}
const CodeGenInstruction::OperandInfo &OI = *Op.OperandInfo;
errs() << OI.Name << " " << OI.Rec->getName()
<< " (" << OI.MIOperandNo << ", " << OI.MINumOperands << ")\n";
}
}
static std::string getEnumNameForToken(const StringRef &Str) {
std::string Res;
for (StringRef::iterator it = Str.begin(), ie = Str.end(); it != ie; ++it) {
switch (*it) {
case '*': Res += "_STAR_"; break;
case '%': Res += "_PCT_"; break;
case ':': Res += "_COLON_"; break;
default:
if (isalnum(*it)) {
Res += *it;
} else {
Res += "_" + utostr((unsigned) *it) + "_";
}
}
}
return Res;
}
ClassInfo *AsmMatcherInfo::getTokenClass(const StringRef &Token) {
ClassInfo *&Entry = TokenClasses[Token];
if (!Entry) {
Entry = new ClassInfo();
Entry->Kind = ClassInfo::Token;
Entry->ClassName = "Token";
Entry->Name = "MCK_" + getEnumNameForToken(Token);
Entry->ValueName = Token;
Entry->PredicateMethod = "<invalid>";
Entry->RenderMethod = "<invalid>";
Classes.push_back(Entry);
}
return Entry;
}
unsigned AsmMatcherInfo::getUserClassKind(const StringRef &Name) {
unsigned &Entry = UserClasses[Name];
if (!Entry)
Entry = ClassInfo::UserClass0 + UserClasses.size() - 1;
return Entry;
}
ClassInfo *
AsmMatcherInfo::getOperandClass(const StringRef &Token,
const CodeGenInstruction::OperandInfo &OI) {
unsigned SuperClass = ClassInfo::Invalid;
std::string ClassName;
if (OI.Rec->isSubClassOf("RegisterClass")) {
ClassName = "Reg";
} else {
try {
ClassName = OI.Rec->getValueAsString("ParserMatchClass");
assert(ClassName != "Reg" && "'Reg' class name is reserved!");
} catch(...) {
PrintError(OI.Rec->getLoc(), "operand has no match class!");
ClassName = "Invalid";
}
// Determine the super class.
try {
std::string SuperClassName =
OI.Rec->getValueAsString("ParserMatchSuperClass");
SuperClass = getUserClassKind(SuperClassName);
} catch(...) { }
}
ClassInfo *&Entry = OperandClasses[ClassName];
if (!Entry) {
Entry = new ClassInfo();
if (ClassName == "Reg") {
Entry->Kind = ClassInfo::Register;
} else {
Entry->Kind = getUserClassKind(ClassName);
Entry->SuperClassKind = SuperClass;
}
Entry->ClassName = ClassName;
Entry->Name = "MCK_" + ClassName;
Entry->ValueName = OI.Rec->getName();
Entry->PredicateMethod = "is" + ClassName;
Entry->RenderMethod = "add" + ClassName + "Operands";
Classes.push_back(Entry);
}
return Entry;
}
void AsmMatcherInfo::BuildInfo(CodeGenTarget &Target) {
for (std::map<std::string, CodeGenInstruction>::const_iterator
it = Target.getInstructions().begin(),
ie = Target.getInstructions().end();
it != ie; ++it) {
const CodeGenInstruction &CGI = it->second;
if (!StringRef(it->first).startswith(MatchPrefix))
continue;
OwningPtr<InstructionInfo> II(new InstructionInfo);
II->InstrName = it->first;
II->Instr = &it->second;
II->AsmString = FlattenVariants(CGI.AsmString, 0);
TokenizeAsmString(II->AsmString, II->Tokens);
// Ignore instructions which shouldn't be matched.
if (!IsAssemblerInstruction(it->first, CGI, II->Tokens))
continue;
for (unsigned i = 0, e = II->Tokens.size(); i != e; ++i) {
StringRef Token = II->Tokens[i];
// Check for simple tokens.
if (Token[0] != '$') {
InstructionInfo::Operand Op;
Op.Class = getTokenClass(Token);
Op.OperandInfo = 0;
II->Operands.push_back(Op);
continue;
}
// Otherwise this is an operand reference.
StringRef OperandName;
if (Token[1] == '{')
OperandName = Token.substr(2, Token.size() - 3);
else
OperandName = Token.substr(1);
// Map this token to an operand. FIXME: Move elsewhere.
unsigned Idx;
try {
Idx = CGI.getOperandNamed(OperandName);
} catch(...) {
errs() << "error: unable to find operand: '" << OperandName << "'!\n";
break;
}
const CodeGenInstruction::OperandInfo &OI = CGI.OperandList[Idx];
InstructionInfo::Operand Op;
Op.Class = getOperandClass(Token, OI);
Op.OperandInfo = &OI;
II->Operands.push_back(Op);
}
// If we broke out, ignore the instruction.
if (II->Operands.size() != II->Tokens.size())
continue;
Instructions.push_back(II.take());
}
// Bind user super classes.
std::map<unsigned, ClassInfo*> UserClasses;
for (unsigned i = 0, e = Classes.size(); i != e; ++i) {
ClassInfo &CI = *Classes[i];
if (CI.isUserClass())
UserClasses[CI.Kind] = &CI;
}
for (unsigned i = 0, e = Classes.size(); i != e; ++i) {
ClassInfo &CI = *Classes[i];
if (CI.isUserClass() && CI.SuperClassKind != ClassInfo::Invalid) {
CI.SuperClass = UserClasses[CI.SuperClassKind];
assert(CI.SuperClass && "Missing super class definition!");
} else {
CI.SuperClass = 0;
}
}
// Reorder classes so that classes preceed super classes.
std::sort(Classes.begin(), Classes.end(), less_ptr<ClassInfo>());
}
static void EmitConvertToMCInst(CodeGenTarget &Target,
std::vector<InstructionInfo*> &Infos,
raw_ostream &OS) {
// Write the convert function to a separate stream, so we can drop it after
// the enum.
std::string ConvertFnBody;
raw_string_ostream CvtOS(ConvertFnBody);
// Function we have already generated.
std::set<std::string> GeneratedFns;
// Start the unified conversion function.
CvtOS << "static bool ConvertToMCInst(ConversionKind Kind, MCInst &Inst, "
<< "unsigned Opcode,\n"
<< " SmallVectorImpl<"
<< Target.getName() << "Operand> &Operands) {\n";
CvtOS << " Inst.setOpcode(Opcode);\n";
CvtOS << " switch (Kind) {\n";
CvtOS << " default:\n";
// Start the enum, which we will generate inline.
OS << "// Unified function for converting operants to MCInst instances.\n\n";
OS << "enum ConversionKind {\n";
for (std::vector<InstructionInfo*>::const_iterator it = Infos.begin(),
ie = Infos.end(); it != ie; ++it) {
InstructionInfo &II = **it;
// Order the (class) operands by the order to convert them into an MCInst.
SmallVector<std::pair<unsigned, unsigned>, 4> MIOperandList;
for (unsigned i = 0, e = II.Operands.size(); i != e; ++i) {
InstructionInfo::Operand &Op = II.Operands[i];
if (Op.OperandInfo)
MIOperandList.push_back(std::make_pair(Op.OperandInfo->MIOperandNo, i));
}
std::sort(MIOperandList.begin(), MIOperandList.end());
// Compute the total number of operands.
unsigned NumMIOperands = 0;
for (unsigned i = 0, e = II.Instr->OperandList.size(); i != e; ++i) {
const CodeGenInstruction::OperandInfo &OI = II.Instr->OperandList[i];
NumMIOperands = std::max(NumMIOperands,
OI.MIOperandNo + OI.MINumOperands);
}
// Build the conversion function signature.
std::string Signature = "Convert";
unsigned CurIndex = 0;
for (unsigned i = 0, e = MIOperandList.size(); i != e; ++i) {
InstructionInfo::Operand &Op = II.Operands[MIOperandList[i].second];
assert(CurIndex <= Op.OperandInfo->MIOperandNo &&
"Duplicate match for instruction operand!");
Signature += "_";
// Skip operands which weren't matched by anything, this occurs when the
// .td file encodes "implicit" operands as explicit ones.
//
// FIXME: This should be removed from the MCInst structure.
for (; CurIndex != Op.OperandInfo->MIOperandNo; ++CurIndex)
Signature += "Imp";
Signature += Op.Class->ClassName;
Signature += utostr(Op.OperandInfo->MINumOperands);
Signature += "_" + utostr(MIOperandList[i].second);
CurIndex += Op.OperandInfo->MINumOperands;
}
// Add any trailing implicit operands.
for (; CurIndex != NumMIOperands; ++CurIndex)
Signature += "Imp";
II.ConversionFnKind = Signature;
// Check if we have already generated this signature.
if (!GeneratedFns.insert(Signature).second)
continue;
// If not, emit it now.
// Add to the enum list.
OS << " " << Signature << ",\n";
// And to the convert function.
CvtOS << " case " << Signature << ":\n";
CurIndex = 0;
for (unsigned i = 0, e = MIOperandList.size(); i != e; ++i) {
InstructionInfo::Operand &Op = II.Operands[MIOperandList[i].second];
// Add the implicit operands.
for (; CurIndex != Op.OperandInfo->MIOperandNo; ++CurIndex)
CvtOS << " Inst.addOperand(MCOperand::CreateReg(0));\n";
CvtOS << " Operands[" << MIOperandList[i].second
<< "]." << Op.Class->RenderMethod
<< "(Inst, " << Op.OperandInfo->MINumOperands << ");\n";
CurIndex += Op.OperandInfo->MINumOperands;
}
// And add trailing implicit operands.
for (; CurIndex != NumMIOperands; ++CurIndex)
CvtOS << " Inst.addOperand(MCOperand::CreateReg(0));\n";
CvtOS << " break;\n";
}
// Finish the convert function.
CvtOS << " }\n";
CvtOS << " return false;\n";
CvtOS << "}\n\n";
// Finish the enum, and drop the convert function after it.
OS << " NumConversionVariants\n";
OS << "};\n\n";
OS << CvtOS.str();
}
/// EmitMatchClassEnumeration - Emit the enumeration for match class kinds.
static void EmitMatchClassEnumeration(CodeGenTarget &Target,
std::vector<ClassInfo*> &Infos,
raw_ostream &OS) {
OS << "namespace {\n\n";
OS << "/// MatchClassKind - The kinds of classes which participate in\n"
<< "/// instruction matching.\n";
OS << "enum MatchClassKind {\n";
OS << " InvalidMatchClass = 0,\n";
for (std::vector<ClassInfo*>::iterator it = Infos.begin(),
ie = Infos.end(); it != ie; ++it) {
ClassInfo &CI = **it;
OS << " " << CI.Name << ", // ";
if (CI.Kind == ClassInfo::Token) {
OS << "'" << CI.ValueName << "'\n";
} else if (CI.Kind == ClassInfo::Register) {
if (!CI.ValueName.empty())
OS << "register class '" << CI.ValueName << "'\n";
else
OS << "derived register class\n";
} else {
OS << "user defined class '" << CI.ValueName << "'\n";
}
}
OS << " NumMatchClassKinds\n";
OS << "};\n\n";
OS << "}\n\n";
}
/// EmitClassifyOperand - Emit the function to classify an operand.
static void EmitClassifyOperand(CodeGenTarget &Target,
std::vector<ClassInfo*> &Infos,
raw_ostream &OS) {
OS << "static MatchClassKind ClassifyOperand("
<< Target.getName() << "Operand &Operand) {\n";
OS << " if (Operand.isToken())\n";
OS << " return MatchTokenString(Operand.getToken());\n\n";
for (std::vector<ClassInfo*>::iterator it = Infos.begin(),
ie = Infos.end(); it != ie; ++it) {
ClassInfo &CI = **it;
if (CI.Kind != ClassInfo::Token) {
OS << " // '" << CI.ClassName << "' class";
if (CI.SuperClass) {
OS << ", subclass of '" << CI.SuperClass->ClassName << "'";
assert(CI < *CI.SuperClass && "Invalid class relation!");
}
OS << "\n";
OS << " if (Operand." << CI.PredicateMethod << "()) {\n";
// Validate subclass relationships.
if (CI.SuperClass)
OS << " assert(Operand." << CI.SuperClass->PredicateMethod
<< "() && \"Invalid class relationship!\");\n";
OS << " return " << CI.Name << ";\n\n";
OS << " }";
}
}
OS << " return InvalidMatchClass;\n";
OS << "}\n\n";
}
typedef std::pair<std::string, std::string> StringPair;
/// FindFirstNonCommonLetter - Find the first character in the keys of the
/// string pairs that is not shared across the whole set of strings. All
/// strings are assumed to have the same length.
static unsigned
FindFirstNonCommonLetter(const std::vector<const StringPair*> &Matches) {
assert(!Matches.empty());
for (unsigned i = 0, e = Matches[0]->first.size(); i != e; ++i) {
// Check to see if letter i is the same across the set.
char Letter = Matches[0]->first[i];
for (unsigned str = 0, e = Matches.size(); str != e; ++str)
if (Matches[str]->first[i] != Letter)
return i;
}
return Matches[0]->first.size();
}
/// EmitStringMatcherForChar - Given a set of strings that are known to be the
/// same length and whose characters leading up to CharNo are the same, emit
/// code to verify that CharNo and later are the same.
///
/// \return - True if control can leave the emitted code fragment.
static bool EmitStringMatcherForChar(const std::string &StrVariableName,
const std::vector<const StringPair*> &Matches,
unsigned CharNo, unsigned IndentCount,
raw_ostream &OS) {
assert(!Matches.empty() && "Must have at least one string to match!");
std::string Indent(IndentCount*2+4, ' ');
// If we have verified that the entire string matches, we're done: output the
// matching code.
if (CharNo == Matches[0]->first.size()) {
assert(Matches.size() == 1 && "Had duplicate keys to match on");
// FIXME: If Matches[0].first has embeded \n, this will be bad.
OS << Indent << Matches[0]->second << "\t // \"" << Matches[0]->first
<< "\"\n";
return false;
}
// Bucket the matches by the character we are comparing.
std::map<char, std::vector<const StringPair*> > MatchesByLetter;
for (unsigned i = 0, e = Matches.size(); i != e; ++i)
MatchesByLetter[Matches[i]->first[CharNo]].push_back(Matches[i]);
// If we have exactly one bucket to match, see how many characters are common
// across the whole set and match all of them at once.
if (MatchesByLetter.size() == 1) {
unsigned FirstNonCommonLetter = FindFirstNonCommonLetter(Matches);
unsigned NumChars = FirstNonCommonLetter-CharNo;
// Emit code to break out if the prefix doesn't match.
if (NumChars == 1) {
// Do the comparison with if (Str[1] != 'f')
// FIXME: Need to escape general characters.
OS << Indent << "if (" << StrVariableName << "[" << CharNo << "] != '"
<< Matches[0]->first[CharNo] << "')\n";
OS << Indent << " break;\n";
} else {
// Do the comparison with if (Str.substr(1,3) != "foo").
// FIXME: Need to escape general strings.
OS << Indent << "if (" << StrVariableName << ".substr(" << CharNo << ","
<< NumChars << ") != \"";
OS << Matches[0]->first.substr(CharNo, NumChars) << "\")\n";
OS << Indent << " break;\n";
}
return EmitStringMatcherForChar(StrVariableName, Matches,
FirstNonCommonLetter, IndentCount, OS);
}
// Otherwise, we have multiple possible things, emit a switch on the
// character.
OS << Indent << "switch (" << StrVariableName << "[" << CharNo << "]) {\n";
OS << Indent << "default: break;\n";
for (std::map<char, std::vector<const StringPair*> >::iterator LI =
MatchesByLetter.begin(), E = MatchesByLetter.end(); LI != E; ++LI) {
// TODO: escape hard stuff (like \n) if we ever care about it.
OS << Indent << "case '" << LI->first << "':\t // "
<< LI->second.size() << " strings to match.\n";
if (EmitStringMatcherForChar(StrVariableName, LI->second, CharNo+1,
IndentCount+1, OS))
OS << Indent << " break;\n";
}
OS << Indent << "}\n";
return true;
}
/// EmitStringMatcher - Given a list of strings and code to execute when they
/// match, output a simple switch tree to classify the input string.
///
/// If a match is found, the code in Vals[i].second is executed; control must
/// not exit this code fragment. If nothing matches, execution falls through.
///
/// \param StrVariableName - The name of the variable to test.
static void EmitStringMatcher(const std::string &StrVariableName,
const std::vector<StringPair> &Matches,
raw_ostream &OS) {
// First level categorization: group strings by length.
std::map<unsigned, std::vector<const StringPair*> > MatchesByLength;
for (unsigned i = 0, e = Matches.size(); i != e; ++i)
MatchesByLength[Matches[i].first.size()].push_back(&Matches[i]);
// Output a switch statement on length and categorize the elements within each
// bin.
OS << " switch (" << StrVariableName << ".size()) {\n";
OS << " default: break;\n";
for (std::map<unsigned, std::vector<const StringPair*> >::iterator LI =
MatchesByLength.begin(), E = MatchesByLength.end(); LI != E; ++LI) {
OS << " case " << LI->first << ":\t // " << LI->second.size()
<< " strings to match.\n";
if (EmitStringMatcherForChar(StrVariableName, LI->second, 0, 0, OS))
OS << " break;\n";
}
OS << " }\n";
}
/// EmitMatchTokenString - Emit the function to match a token string to the
/// appropriate match class value.
static void EmitMatchTokenString(CodeGenTarget &Target,
std::vector<ClassInfo*> &Infos,
raw_ostream &OS) {
// Construct the match list.
std::vector<StringPair> Matches;
for (std::vector<ClassInfo*>::iterator it = Infos.begin(),
ie = Infos.end(); it != ie; ++it) {
ClassInfo &CI = **it;
if (CI.Kind == ClassInfo::Token)
Matches.push_back(StringPair(CI.ValueName, "return " + CI.Name + ";"));
}
OS << "static MatchClassKind MatchTokenString(const StringRef &Name) {\n";
EmitStringMatcher("Name", Matches, OS);
OS << " return InvalidMatchClass;\n";
OS << "}\n\n";
}
/// EmitMatchRegisterName - Emit the function to match a string to the target
/// specific register enum.
static void EmitMatchRegisterName(CodeGenTarget &Target, Record *AsmParser,
raw_ostream &OS) {
// Construct the match list.
std::vector<StringPair> Matches;
for (unsigned i = 0, e = Target.getRegisters().size(); i != e; ++i) {
const CodeGenRegister &Reg = Target.getRegisters()[i];
if (Reg.TheDef->getValueAsString("AsmName").empty())
continue;
Matches.push_back(StringPair(Reg.TheDef->getValueAsString("AsmName"),
"return " + utostr(i + 1) + ";"));
}
OS << "unsigned " << Target.getName()
<< AsmParser->getValueAsString("AsmParserClassName")
<< "::MatchRegisterName(const StringRef &Name) {\n";
EmitStringMatcher("Name", Matches, OS);
OS << " return 0;\n";
OS << "}\n\n";
}
void AsmMatcherEmitter::run(raw_ostream &OS) {
CodeGenTarget Target;
Record *AsmParser = Target.getAsmParser();
std::string ClassName = AsmParser->getValueAsString("AsmParserClassName");
EmitSourceFileHeader("Assembly Matcher Source Fragment", OS);
// Emit the function to match a register name to number.
EmitMatchRegisterName(Target, AsmParser, OS);
// Compute the information on the instructions to match.
AsmMatcherInfo Info;
Info.BuildInfo(Target);
// Sort the instruction table using the partial order on classes.
std::sort(Info.Instructions.begin(), Info.Instructions.end(),
less_ptr<InstructionInfo>());
DEBUG_WITH_TYPE("instruction_info", {
for (std::vector<InstructionInfo*>::iterator
it = Info.Instructions.begin(), ie = Info.Instructions.end();
it != ie; ++it)
(*it)->dump();
});
// Check for ambiguous instructions.
unsigned NumAmbiguous = 0;
for (unsigned i = 0, e = Info.Instructions.size(); i != e; ++i) {
for (unsigned j = i + 1; j != e; ++j) {
InstructionInfo &A = *Info.Instructions[i];
InstructionInfo &B = *Info.Instructions[j];
if (A.CouldMatchAmiguouslyWith(B)) {
DEBUG_WITH_TYPE("ambiguous_instrs", {
errs() << "warning: ambiguous instruction match:\n";
A.dump();
errs() << "\nis incomparable with:\n";
B.dump();
errs() << "\n\n";
});
++NumAmbiguous;
}
}
}
if (NumAmbiguous)
DEBUG_WITH_TYPE("ambiguous_instrs", {
errs() << "warning: " << NumAmbiguous
<< " ambiguous instructions!\n";
});
// Generate the unified function to convert operands into an MCInst.
EmitConvertToMCInst(Target, Info.Instructions, OS);
// Emit the enumeration for classes which participate in matching.
EmitMatchClassEnumeration(Target, Info.Classes, OS);
// Emit the routine to match token strings to their match class.
EmitMatchTokenString(Target, Info.Classes, OS);
// Emit the routine to classify an operand.
EmitClassifyOperand(Target, Info.Classes, OS);
// Finally, build the match function.
size_t MaxNumOperands = 0;
for (std::vector<InstructionInfo*>::const_iterator it =
Info.Instructions.begin(), ie = Info.Instructions.end();
it != ie; ++it)
MaxNumOperands = std::max(MaxNumOperands, (*it)->Operands.size());
OS << "bool " << Target.getName() << ClassName
<< "::MatchInstruction("
<< "SmallVectorImpl<" << Target.getName() << "Operand> &Operands, "
<< "MCInst &Inst) {\n";
// Emit the static match table; unused classes get initalized to 0 which is
// guaranteed to be InvalidMatchClass.
//
// FIXME: We can reduce the size of this table very easily. First, we change
// it so that store the kinds in separate bit-fields for each index, which
// only needs to be the max width used for classes at that index (we also need
// to reject based on this during classification). If we then make sure to
// order the match kinds appropriately (putting mnemonics last), then we
// should only end up using a few bits for each class, especially the ones
// following the mnemonic.
OS << " static const struct MatchEntry {\n";
OS << " unsigned Opcode;\n";
OS << " ConversionKind ConvertFn;\n";
OS << " MatchClassKind Classes[" << MaxNumOperands << "];\n";
OS << " } MatchTable[" << Info.Instructions.size() << "] = {\n";
for (std::vector<InstructionInfo*>::const_iterator it =
Info.Instructions.begin(), ie = Info.Instructions.end();
it != ie; ++it) {
InstructionInfo &II = **it;
OS << " { " << Target.getName() << "::" << II.InstrName
<< ", " << II.ConversionFnKind << ", { ";
for (unsigned i = 0, e = II.Operands.size(); i != e; ++i) {
InstructionInfo::Operand &Op = II.Operands[i];
if (i) OS << ", ";
OS << Op.Class->Name;
}
OS << " } },\n";
}
OS << " };\n\n";
// Emit code to compute the class list for this operand vector.
OS << " // Eliminate obvious mismatches.\n";
OS << " if (Operands.size() > " << MaxNumOperands << ")\n";
OS << " return true;\n\n";
OS << " // Compute the class list for this operand vector.\n";
OS << " MatchClassKind Classes[" << MaxNumOperands << "];\n";
OS << " for (unsigned i = 0, e = Operands.size(); i != e; ++i) {\n";
OS << " Classes[i] = ClassifyOperand(Operands[i]);\n\n";
OS << " // Check for invalid operands before matching.\n";
OS << " if (Classes[i] == InvalidMatchClass)\n";
OS << " return true;\n";
OS << " }\n\n";
OS << " // Mark unused classes.\n";
OS << " for (unsigned i = Operands.size(), e = " << MaxNumOperands << "; "
<< "i != e; ++i)\n";
OS << " Classes[i] = InvalidMatchClass;\n\n";
// Emit code to search the table.
OS << " // Search the table.\n";
OS << " for (const MatchEntry *it = MatchTable, "
<< "*ie = MatchTable + " << Info.Instructions.size()
<< "; it != ie; ++it) {\n";
for (unsigned i = 0; i != MaxNumOperands; ++i) {
OS << " if (Classes[" << i << "] != it->Classes[" << i << "])\n";
OS << " continue;\n";
}
OS << "\n";
OS << " return ConvertToMCInst(it->ConvertFn, Inst, "
<< "it->Opcode, Operands);\n";
OS << " }\n\n";
OS << " return true;\n";
OS << "}\n\n";
}
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