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llvm-mirror/tools/llvm-mc/AsmParser.cpp
Daniel Dunbar 1960440e70 llvm-mc: Emit parsed instructions to the MCStreamer. 
llvm-svn: 74594
2009-07-01 06:35:48 +00:00

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//===- AsmParser.cpp - Parser for Assembly Files --------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This class implements the parser for assembly files.
//
//===----------------------------------------------------------------------===//
#include "AsmParser.h"
#include "AsmExpr.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
void AsmParser::Warning(SMLoc L, const char *Msg) {
Lexer.PrintMessage(L, Msg, "warning");
}
bool AsmParser::Error(SMLoc L, const char *Msg) {
Lexer.PrintMessage(L, Msg, "error");
return true;
}
bool AsmParser::TokError(const char *Msg) {
Lexer.PrintMessage(Lexer.getLoc(), Msg, "error");
return true;
}
bool AsmParser::Run() {
// Prime the lexer.
Lexer.Lex();
while (Lexer.isNot(asmtok::Eof))
if (ParseStatement())
return true;
return false;
}
/// EatToEndOfStatement - Throw away the rest of the line for testing purposes.
void AsmParser::EatToEndOfStatement() {
while (Lexer.isNot(asmtok::EndOfStatement) &&
Lexer.isNot(asmtok::Eof))
Lexer.Lex();
// Eat EOL.
if (Lexer.is(asmtok::EndOfStatement))
Lexer.Lex();
}
/// ParseParenExpr - Parse a paren expression and return it.
/// NOTE: This assumes the leading '(' has already been consumed.
///
/// parenexpr ::= expr)
///
bool AsmParser::ParseParenExpr(AsmExpr *&Res) {
if (ParseExpression(Res)) return true;
if (Lexer.isNot(asmtok::RParen))
return TokError("expected ')' in parentheses expression");
Lexer.Lex();
return false;
}
/// ParsePrimaryExpr - Parse a primary expression and return it.
/// primaryexpr ::= (parenexpr
/// primaryexpr ::= symbol
/// primaryexpr ::= number
/// primaryexpr ::= ~,+,- primaryexpr
bool AsmParser::ParsePrimaryExpr(AsmExpr *&Res) {
switch (Lexer.getKind()) {
default:
return TokError("unknown token in expression");
case asmtok::Exclaim:
Lexer.Lex(); // Eat the operator.
if (ParsePrimaryExpr(Res))
return true;
Res = new AsmUnaryExpr(AsmUnaryExpr::LNot, Res);
return false;
case asmtok::Identifier: {
// This is a label, this should be parsed as part of an expression, to
// handle things like LFOO+4.
MCSymbol *Sym = Ctx.GetOrCreateSymbol(Lexer.getCurStrVal());
// If this is use of an undefined symbol then mark it external.
if (!Sym->getSection() && !Ctx.GetSymbolValue(Sym))
Sym->setExternal(true);
Res = new AsmSymbolRefExpr(Sym);
Lexer.Lex(); // Eat identifier.
return false;
}
case asmtok::IntVal:
Res = new AsmConstantExpr(Lexer.getCurIntVal());
Lexer.Lex(); // Eat identifier.
return false;
case asmtok::LParen:
Lexer.Lex(); // Eat the '('.
return ParseParenExpr(Res);
case asmtok::Minus:
Lexer.Lex(); // Eat the operator.
if (ParsePrimaryExpr(Res))
return true;
Res = new AsmUnaryExpr(AsmUnaryExpr::Minus, Res);
return false;
case asmtok::Plus:
Lexer.Lex(); // Eat the operator.
if (ParsePrimaryExpr(Res))
return true;
Res = new AsmUnaryExpr(AsmUnaryExpr::Plus, Res);
return false;
case asmtok::Tilde:
Lexer.Lex(); // Eat the operator.
if (ParsePrimaryExpr(Res))
return true;
Res = new AsmUnaryExpr(AsmUnaryExpr::Not, Res);
return false;
}
}
/// ParseExpression - Parse an expression and return it.
///
/// expr ::= expr +,- expr -> lowest.
/// expr ::= expr |,^,&,! expr -> middle.
/// expr ::= expr *,/,%,<<,>> expr -> highest.
/// expr ::= primaryexpr
///
bool AsmParser::ParseExpression(AsmExpr *&Res) {
Res = 0;
return ParsePrimaryExpr(Res) ||
ParseBinOpRHS(1, Res);
}
bool AsmParser::ParseAbsoluteExpression(int64_t &Res) {
AsmExpr *Expr;
SMLoc StartLoc = Lexer.getLoc();
if (ParseExpression(Expr))
return true;
if (!Expr->EvaluateAsAbsolute(Ctx, Res))
return Error(StartLoc, "expected absolute expression");
return false;
}
bool AsmParser::ParseRelocatableExpression(MCValue &Res) {
AsmExpr *Expr;
SMLoc StartLoc = Lexer.getLoc();
if (ParseExpression(Expr))
return true;
if (!Expr->EvaluateAsRelocatable(Ctx, Res))
return Error(StartLoc, "expected relocatable expression");
return false;
}
static unsigned getBinOpPrecedence(asmtok::TokKind K,
AsmBinaryExpr::Opcode &Kind) {
switch (K) {
default: return 0; // not a binop.
// Lowest Precedence: &&, ||
case asmtok::AmpAmp:
Kind = AsmBinaryExpr::LAnd;
return 1;
case asmtok::PipePipe:
Kind = AsmBinaryExpr::LOr;
return 1;
// Low Precedence: +, -, ==, !=, <>, <, <=, >, >=
case asmtok::Plus:
Kind = AsmBinaryExpr::Add;
return 2;
case asmtok::Minus:
Kind = AsmBinaryExpr::Sub;
return 2;
case asmtok::EqualEqual:
Kind = AsmBinaryExpr::EQ;
return 2;
case asmtok::ExclaimEqual:
case asmtok::LessGreater:
Kind = AsmBinaryExpr::NE;
return 2;
case asmtok::Less:
Kind = AsmBinaryExpr::LT;
return 2;
case asmtok::LessEqual:
Kind = AsmBinaryExpr::LTE;
return 2;
case asmtok::Greater:
Kind = AsmBinaryExpr::GT;
return 2;
case asmtok::GreaterEqual:
Kind = AsmBinaryExpr::GTE;
return 2;
// Intermediate Precedence: |, &, ^
//
// FIXME: gas seems to support '!' as an infix operator?
case asmtok::Pipe:
Kind = AsmBinaryExpr::Or;
return 3;
case asmtok::Caret:
Kind = AsmBinaryExpr::Xor;
return 3;
case asmtok::Amp:
Kind = AsmBinaryExpr::And;
return 3;
// Highest Precedence: *, /, %, <<, >>
case asmtok::Star:
Kind = AsmBinaryExpr::Mul;
return 4;
case asmtok::Slash:
Kind = AsmBinaryExpr::Div;
return 4;
case asmtok::Percent:
Kind = AsmBinaryExpr::Mod;
return 4;
case asmtok::LessLess:
Kind = AsmBinaryExpr::Shl;
return 4;
case asmtok::GreaterGreater:
Kind = AsmBinaryExpr::Shr;
return 4;
}
}
/// ParseBinOpRHS - Parse all binary operators with precedence >= 'Precedence'.
/// Res contains the LHS of the expression on input.
bool AsmParser::ParseBinOpRHS(unsigned Precedence, AsmExpr *&Res) {
while (1) {
AsmBinaryExpr::Opcode Kind = AsmBinaryExpr::Add;
unsigned TokPrec = getBinOpPrecedence(Lexer.getKind(), Kind);
// If the next token is lower precedence than we are allowed to eat, return
// successfully with what we ate already.
if (TokPrec < Precedence)
return false;
Lexer.Lex();
// Eat the next primary expression.
AsmExpr *RHS;
if (ParsePrimaryExpr(RHS)) return true;
// If BinOp binds less tightly with RHS than the operator after RHS, let
// the pending operator take RHS as its LHS.
AsmBinaryExpr::Opcode Dummy;
unsigned NextTokPrec = getBinOpPrecedence(Lexer.getKind(), Dummy);
if (TokPrec < NextTokPrec) {
if (ParseBinOpRHS(Precedence+1, RHS)) return true;
}
// Merge LHS and RHS according to operator.
Res = new AsmBinaryExpr(Kind, Res, RHS);
}
}
/// ParseStatement:
/// ::= EndOfStatement
/// ::= Label* Directive ...Operands... EndOfStatement
/// ::= Label* Identifier OperandList* EndOfStatement
bool AsmParser::ParseStatement() {
switch (Lexer.getKind()) {
default:
return TokError("unexpected token at start of statement");
case asmtok::EndOfStatement:
Lexer.Lex();
return false;
case asmtok::Identifier:
break;
// TODO: Recurse on local labels etc.
}
// If we have an identifier, handle it as the key symbol.
SMLoc IDLoc = Lexer.getLoc();
const char *IDVal = Lexer.getCurStrVal();
// Consume the identifier, see what is after it.
switch (Lexer.Lex()) {
case asmtok::Colon: {
// identifier ':' -> Label.
Lexer.Lex();
// Diagnose attempt to use a variable as a label.
//
// FIXME: Diagnostics. Note the location of the definition as a label.
// FIXME: This doesn't diagnose assignment to a symbol which has been
// implicitly marked as external.
MCSymbol *Sym = Ctx.GetOrCreateSymbol(IDVal);
if (Sym->getSection())
return Error(IDLoc, "invalid symbol redefinition");
if (Ctx.GetSymbolValue(Sym))
return Error(IDLoc, "symbol already used as assembler variable");
// Since we saw a label, create a symbol and emit it.
// FIXME: If the label starts with L it is an assembler temporary label.
// Why does the client of this api need to know this?
Out.EmitLabel(Sym);
return ParseStatement();
}
case asmtok::Equal:
// identifier '=' ... -> assignment statement
Lexer.Lex();
return ParseAssignment(IDVal, false);
default: // Normal instruction or directive.
break;
}
// Otherwise, we have a normal instruction or directive.
if (IDVal[0] == '.') {
// FIXME: This should be driven based on a hash lookup and callback.
if (!strcmp(IDVal, ".section"))
return ParseDirectiveDarwinSection();
if (!strcmp(IDVal, ".text"))
// FIXME: This changes behavior based on the -static flag to the
// assembler.
return ParseDirectiveSectionSwitch("__TEXT,__text",
"regular,pure_instructions");
if (!strcmp(IDVal, ".const"))
return ParseDirectiveSectionSwitch("__TEXT,__const");
if (!strcmp(IDVal, ".static_const"))
return ParseDirectiveSectionSwitch("__TEXT,__static_const");
if (!strcmp(IDVal, ".cstring"))
return ParseDirectiveSectionSwitch("__TEXT,__cstring",
"cstring_literals");
if (!strcmp(IDVal, ".literal4"))
return ParseDirectiveSectionSwitch("__TEXT,__literal4", "4byte_literals");
if (!strcmp(IDVal, ".literal8"))
return ParseDirectiveSectionSwitch("__TEXT,__literal8", "8byte_literals");
if (!strcmp(IDVal, ".literal16"))
return ParseDirectiveSectionSwitch("__TEXT,__literal16",
"16byte_literals");
if (!strcmp(IDVal, ".constructor"))
return ParseDirectiveSectionSwitch("__TEXT,__constructor");
if (!strcmp(IDVal, ".destructor"))
return ParseDirectiveSectionSwitch("__TEXT,__destructor");
if (!strcmp(IDVal, ".fvmlib_init0"))
return ParseDirectiveSectionSwitch("__TEXT,__fvmlib_init0");
if (!strcmp(IDVal, ".fvmlib_init1"))
return ParseDirectiveSectionSwitch("__TEXT,__fvmlib_init1");
if (!strcmp(IDVal, ".symbol_stub")) // FIXME: Different on PPC.
return ParseDirectiveSectionSwitch("__IMPORT,__jump_table,symbol_stubs",
"self_modifying_code+pure_instructions,5");
// FIXME: .picsymbol_stub on PPC.
if (!strcmp(IDVal, ".data"))
return ParseDirectiveSectionSwitch("__DATA,__data");
if (!strcmp(IDVal, ".static_data"))
return ParseDirectiveSectionSwitch("__DATA,__static_data");
if (!strcmp(IDVal, ".non_lazy_symbol_pointer"))
return ParseDirectiveSectionSwitch("__DATA,__nl_symbol_pointer",
"non_lazy_symbol_pointers");
if (!strcmp(IDVal, ".lazy_symbol_pointer"))
return ParseDirectiveSectionSwitch("__DATA,__la_symbol_pointer",
"lazy_symbol_pointers");
if (!strcmp(IDVal, ".dyld"))
return ParseDirectiveSectionSwitch("__DATA,__dyld");
if (!strcmp(IDVal, ".mod_init_func"))
return ParseDirectiveSectionSwitch("__DATA,__mod_init_func",
"mod_init_funcs");
if (!strcmp(IDVal, ".mod_term_func"))
return ParseDirectiveSectionSwitch("__DATA,__mod_term_func",
"mod_term_funcs");
if (!strcmp(IDVal, ".const_data"))
return ParseDirectiveSectionSwitch("__DATA,__const", "regular");
// FIXME: Verify attributes on sections.
if (!strcmp(IDVal, ".objc_class"))
return ParseDirectiveSectionSwitch("__OBJC,__class");
if (!strcmp(IDVal, ".objc_meta_class"))
return ParseDirectiveSectionSwitch("__OBJC,__meta_class");
if (!strcmp(IDVal, ".objc_cat_cls_meth"))
return ParseDirectiveSectionSwitch("__OBJC,__cat_cls_meth");
if (!strcmp(IDVal, ".objc_cat_inst_meth"))
return ParseDirectiveSectionSwitch("__OBJC,__cat_inst_meth");
if (!strcmp(IDVal, ".objc_protocol"))
return ParseDirectiveSectionSwitch("__OBJC,__protocol");
if (!strcmp(IDVal, ".objc_string_object"))
return ParseDirectiveSectionSwitch("__OBJC,__string_object");
if (!strcmp(IDVal, ".objc_cls_meth"))
return ParseDirectiveSectionSwitch("__OBJC,__cls_meth");
if (!strcmp(IDVal, ".objc_inst_meth"))
return ParseDirectiveSectionSwitch("__OBJC,__inst_meth");
if (!strcmp(IDVal, ".objc_cls_refs"))
return ParseDirectiveSectionSwitch("__OBJC,__cls_refs");
if (!strcmp(IDVal, ".objc_message_refs"))
return ParseDirectiveSectionSwitch("__OBJC,__message_refs");
if (!strcmp(IDVal, ".objc_symbols"))
return ParseDirectiveSectionSwitch("__OBJC,__symbols");
if (!strcmp(IDVal, ".objc_category"))
return ParseDirectiveSectionSwitch("__OBJC,__category");
if (!strcmp(IDVal, ".objc_class_vars"))
return ParseDirectiveSectionSwitch("__OBJC,__class_vars");
if (!strcmp(IDVal, ".objc_instance_vars"))
return ParseDirectiveSectionSwitch("__OBJC,__instance_vars");
if (!strcmp(IDVal, ".objc_module_info"))
return ParseDirectiveSectionSwitch("__OBJC,__module_info");
if (!strcmp(IDVal, ".objc_class_names"))
return ParseDirectiveSectionSwitch("__TEXT,__cstring","cstring_literals");
if (!strcmp(IDVal, ".objc_meth_var_types"))
return ParseDirectiveSectionSwitch("__TEXT,__cstring","cstring_literals");
if (!strcmp(IDVal, ".objc_meth_var_names"))
return ParseDirectiveSectionSwitch("__TEXT,__cstring","cstring_literals");
if (!strcmp(IDVal, ".objc_selector_strs"))
return ParseDirectiveSectionSwitch("__OBJC,__selector_strs");
// Assembler features
if (!strcmp(IDVal, ".set"))
return ParseDirectiveSet();
// Data directives
if (!strcmp(IDVal, ".ascii"))
return ParseDirectiveAscii(false);
if (!strcmp(IDVal, ".asciz"))
return ParseDirectiveAscii(true);
// FIXME: Target hooks for size? Also for "word", "hword".
if (!strcmp(IDVal, ".byte"))
return ParseDirectiveValue(1);
if (!strcmp(IDVal, ".short"))
return ParseDirectiveValue(2);
if (!strcmp(IDVal, ".long"))
return ParseDirectiveValue(4);
if (!strcmp(IDVal, ".quad"))
return ParseDirectiveValue(8);
// FIXME: Target hooks for IsPow2.
if (!strcmp(IDVal, ".align"))
return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/1);
if (!strcmp(IDVal, ".align32"))
return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/4);
if (!strcmp(IDVal, ".balign"))
return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/1);
if (!strcmp(IDVal, ".balignw"))
return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/2);
if (!strcmp(IDVal, ".balignl"))
return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/4);
if (!strcmp(IDVal, ".p2align"))
return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/1);
if (!strcmp(IDVal, ".p2alignw"))
return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/2);
if (!strcmp(IDVal, ".p2alignl"))
return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/4);
if (!strcmp(IDVal, ".org"))
return ParseDirectiveOrg();
if (!strcmp(IDVal, ".fill"))
return ParseDirectiveFill();
if (!strcmp(IDVal, ".space"))
return ParseDirectiveSpace();
// Symbol attribute directives
if (!strcmp(IDVal, ".globl") || !strcmp(IDVal, ".global"))
return ParseDirectiveSymbolAttribute(MCStreamer::Global);
if (!strcmp(IDVal, ".hidden"))
return ParseDirectiveSymbolAttribute(MCStreamer::Hidden);
if (!strcmp(IDVal, ".indirect_symbol"))
return ParseDirectiveSymbolAttribute(MCStreamer::IndirectSymbol);
if (!strcmp(IDVal, ".internal"))
return ParseDirectiveSymbolAttribute(MCStreamer::Internal);
if (!strcmp(IDVal, ".lazy_reference"))
return ParseDirectiveSymbolAttribute(MCStreamer::LazyReference);
if (!strcmp(IDVal, ".no_dead_strip"))
return ParseDirectiveSymbolAttribute(MCStreamer::NoDeadStrip);
if (!strcmp(IDVal, ".private_extern"))
return ParseDirectiveSymbolAttribute(MCStreamer::PrivateExtern);
if (!strcmp(IDVal, ".protected"))
return ParseDirectiveSymbolAttribute(MCStreamer::Protected);
if (!strcmp(IDVal, ".reference"))
return ParseDirectiveSymbolAttribute(MCStreamer::Reference);
if (!strcmp(IDVal, ".weak"))
return ParseDirectiveSymbolAttribute(MCStreamer::Weak);
if (!strcmp(IDVal, ".weak_definition"))
return ParseDirectiveSymbolAttribute(MCStreamer::WeakDefinition);
if (!strcmp(IDVal, ".weak_reference"))
return ParseDirectiveSymbolAttribute(MCStreamer::WeakReference);
Warning(IDLoc, "ignoring directive for now");
EatToEndOfStatement();
return false;
}
MCInst Inst;
if (ParseX86InstOperands(IDVal, Inst))
return true;
if (Lexer.isNot(asmtok::EndOfStatement))
return TokError("unexpected token in argument list");
// Eat the end of statement marker.
Lexer.Lex();
// Instruction is good, process it.
Out.EmitInstruction(Inst);
// Skip to end of line for now.
return false;
}
bool AsmParser::ParseAssignment(const char *Name, bool IsDotSet) {
// FIXME: Use better location, we should use proper tokens.
SMLoc EqualLoc = Lexer.getLoc();
MCValue Value;
if (ParseRelocatableExpression(Value))
return true;
if (Lexer.isNot(asmtok::EndOfStatement))
return TokError("unexpected token in assignment");
// Eat the end of statement marker.
Lexer.Lex();
// Diagnose assignment to a label.
//
// FIXME: Diagnostics. Note the location of the definition as a label.
// FIXME: This doesn't diagnose assignment to a symbol which has been
// implicitly marked as external.
// FIXME: Handle '.'.
// FIXME: Diagnose assignment to protected identifier (e.g., register name).
MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name);
if (Sym->getSection())
return Error(EqualLoc, "invalid assignment to symbol emitted as a label");
if (Sym->isExternal())
return Error(EqualLoc, "invalid assignment to external symbol");
// Do the assignment.
Out.EmitAssignment(Sym, Value, IsDotSet);
return false;
}
/// ParseDirectiveSet:
/// ::= .set identifier ',' expression
bool AsmParser::ParseDirectiveSet() {
if (Lexer.isNot(asmtok::Identifier))
return TokError("expected identifier after '.set' directive");
const char *Name = Lexer.getCurStrVal();
if (Lexer.Lex() != asmtok::Comma)
return TokError("unexpected token in '.set'");
Lexer.Lex();
return ParseAssignment(Name, true);
}
/// ParseDirectiveSection:
/// ::= .section identifier (',' identifier)*
/// FIXME: This should actually parse out the segment, section, attributes and
/// sizeof_stub fields.
bool AsmParser::ParseDirectiveDarwinSection() {
if (Lexer.isNot(asmtok::Identifier))
return TokError("expected identifier after '.section' directive");
std::string Section = Lexer.getCurStrVal();
Lexer.Lex();
// Accept a comma separated list of modifiers.
while (Lexer.is(asmtok::Comma)) {
Lexer.Lex();
if (Lexer.isNot(asmtok::Identifier))
return TokError("expected identifier in '.section' directive");
Section += ',';
Section += Lexer.getCurStrVal();
Lexer.Lex();
}
if (Lexer.isNot(asmtok::EndOfStatement))
return TokError("unexpected token in '.section' directive");
Lexer.Lex();
Out.SwitchSection(Ctx.GetSection(Section.c_str()));
return false;
}
bool AsmParser::ParseDirectiveSectionSwitch(const char *Section,
const char *Directives) {
if (Lexer.isNot(asmtok::EndOfStatement))
return TokError("unexpected token in section switching directive");
Lexer.Lex();
std::string SectionStr = Section;
if (Directives && Directives[0]) {
SectionStr += ",";
SectionStr += Directives;
}
Out.SwitchSection(Ctx.GetSection(Section));
return false;
}
/// ParseDirectiveAscii:
/// ::= ( .ascii | .asciz ) [ "string" ( , "string" )* ]
bool AsmParser::ParseDirectiveAscii(bool ZeroTerminated) {
if (Lexer.isNot(asmtok::EndOfStatement)) {
for (;;) {
if (Lexer.isNot(asmtok::String))
return TokError("expected string in '.ascii' or '.asciz' directive");
// FIXME: This shouldn't use a const char* + strlen, the string could have
// embedded nulls.
// FIXME: Should have accessor for getting string contents.
const char *Str = Lexer.getCurStrVal();
Out.EmitBytes(Str + 1, strlen(Str) - 2);
if (ZeroTerminated)
Out.EmitBytes("\0", 1);
Lexer.Lex();
if (Lexer.is(asmtok::EndOfStatement))
break;
if (Lexer.isNot(asmtok::Comma))
return TokError("unexpected token in '.ascii' or '.asciz' directive");
Lexer.Lex();
}
}
Lexer.Lex();
return false;
}
/// ParseDirectiveValue
/// ::= (.byte | .short | ... ) [ expression (, expression)* ]
bool AsmParser::ParseDirectiveValue(unsigned Size) {
if (Lexer.isNot(asmtok::EndOfStatement)) {
for (;;) {
MCValue Expr;
if (ParseRelocatableExpression(Expr))
return true;
Out.EmitValue(Expr, Size);
if (Lexer.is(asmtok::EndOfStatement))
break;
// FIXME: Improve diagnostic.
if (Lexer.isNot(asmtok::Comma))
return TokError("unexpected token in directive");
Lexer.Lex();
}
}
Lexer.Lex();
return false;
}
/// ParseDirectiveSpace
/// ::= .space expression [ , expression ]
bool AsmParser::ParseDirectiveSpace() {
int64_t NumBytes;
if (ParseAbsoluteExpression(NumBytes))
return true;
int64_t FillExpr = 0;
bool HasFillExpr = false;
if (Lexer.isNot(asmtok::EndOfStatement)) {
if (Lexer.isNot(asmtok::Comma))
return TokError("unexpected token in '.space' directive");
Lexer.Lex();
if (ParseAbsoluteExpression(FillExpr))
return true;
HasFillExpr = true;
if (Lexer.isNot(asmtok::EndOfStatement))
return TokError("unexpected token in '.space' directive");
}
Lexer.Lex();
if (NumBytes <= 0)
return TokError("invalid number of bytes in '.space' directive");
// FIXME: Sometimes the fill expr is 'nop' if it isn't supplied, instead of 0.
for (uint64_t i = 0, e = NumBytes; i != e; ++i)
Out.EmitValue(MCValue::get(FillExpr), 1);
return false;
}
/// ParseDirectiveFill
/// ::= .fill expression , expression , expression
bool AsmParser::ParseDirectiveFill() {
int64_t NumValues;
if (ParseAbsoluteExpression(NumValues))
return true;
if (Lexer.isNot(asmtok::Comma))
return TokError("unexpected token in '.fill' directive");
Lexer.Lex();
int64_t FillSize;
if (ParseAbsoluteExpression(FillSize))
return true;
if (Lexer.isNot(asmtok::Comma))
return TokError("unexpected token in '.fill' directive");
Lexer.Lex();
int64_t FillExpr;
if (ParseAbsoluteExpression(FillExpr))
return true;
if (Lexer.isNot(asmtok::EndOfStatement))
return TokError("unexpected token in '.fill' directive");
Lexer.Lex();
if (FillSize != 1 && FillSize != 2 && FillSize != 4)
return TokError("invalid '.fill' size, expected 1, 2, or 4");
for (uint64_t i = 0, e = NumValues; i != e; ++i)
Out.EmitValue(MCValue::get(FillExpr), FillSize);
return false;
}
/// ParseDirectiveOrg
/// ::= .org expression [ , expression ]
bool AsmParser::ParseDirectiveOrg() {
MCValue Offset;
if (ParseRelocatableExpression(Offset))
return true;
// Parse optional fill expression.
int64_t FillExpr = 0;
if (Lexer.isNot(asmtok::EndOfStatement)) {
if (Lexer.isNot(asmtok::Comma))
return TokError("unexpected token in '.org' directive");
Lexer.Lex();
if (ParseAbsoluteExpression(FillExpr))
return true;
if (Lexer.isNot(asmtok::EndOfStatement))
return TokError("unexpected token in '.org' directive");
}
Lexer.Lex();
// FIXME: Only limited forms of relocatable expressions are accepted here, it
// has to be relative to the current section.
Out.EmitValueToOffset(Offset, FillExpr);
return false;
}
/// ParseDirectiveAlign
/// ::= {.align, ...} expression [ , expression [ , expression ]]
bool AsmParser::ParseDirectiveAlign(bool IsPow2, unsigned ValueSize) {
int64_t Alignment;
if (ParseAbsoluteExpression(Alignment))
return true;
SMLoc MaxBytesLoc;
bool HasFillExpr = false;
int64_t FillExpr = 0;
int64_t MaxBytesToFill = 0;
if (Lexer.isNot(asmtok::EndOfStatement)) {
if (Lexer.isNot(asmtok::Comma))
return TokError("unexpected token in directive");
Lexer.Lex();
// The fill expression can be omitted while specifying a maximum number of
// alignment bytes, e.g:
// .align 3,,4
if (Lexer.isNot(asmtok::Comma)) {
HasFillExpr = true;
if (ParseAbsoluteExpression(FillExpr))
return true;
}
if (Lexer.isNot(asmtok::EndOfStatement)) {
if (Lexer.isNot(asmtok::Comma))
return TokError("unexpected token in directive");
Lexer.Lex();
MaxBytesLoc = Lexer.getLoc();
if (ParseAbsoluteExpression(MaxBytesToFill))
return true;
if (Lexer.isNot(asmtok::EndOfStatement))
return TokError("unexpected token in directive");
}
}
Lexer.Lex();
if (!HasFillExpr) {
// FIXME: Sometimes fill with nop.
FillExpr = 0;
}
// Compute alignment in bytes.
if (IsPow2) {
// FIXME: Diagnose overflow.
Alignment = 1 << Alignment;
}
// Diagnose non-sensical max bytes to fill.
if (MaxBytesLoc.isValid()) {
if (MaxBytesToFill < 1) {
Warning(MaxBytesLoc, "alignment directive can never be satisfied in this "
"many bytes, ignoring");
return false;
}
if (MaxBytesToFill >= Alignment) {
Warning(MaxBytesLoc, "maximum bytes expression exceeds alignment and "
"has no effect");
MaxBytesToFill = 0;
}
}
// FIXME: Target specific behavior about how the "extra" bytes are filled.
Out.EmitValueToAlignment(Alignment, FillExpr, ValueSize, MaxBytesToFill);
return false;
}
/// ParseDirectiveSymbolAttribute
/// ::= { ".globl", ".weak", ... } [ identifier ( , identifier )* ]
bool AsmParser::ParseDirectiveSymbolAttribute(MCStreamer::SymbolAttr Attr) {
if (Lexer.isNot(asmtok::EndOfStatement)) {
for (;;) {
if (Lexer.isNot(asmtok::Identifier))
return TokError("expected identifier in directive");
MCSymbol *Sym = Ctx.GetOrCreateSymbol(Lexer.getCurStrVal());
Lexer.Lex();
// If this is use of an undefined symbol then mark it external.
if (!Sym->getSection() && !Ctx.GetSymbolValue(Sym))
Sym->setExternal(true);
Out.EmitSymbolAttribute(Sym, Attr);
if (Lexer.is(asmtok::EndOfStatement))
break;
if (Lexer.isNot(asmtok::Comma))
return TokError("unexpected token in directive");
Lexer.Lex();
}
}
Lexer.Lex();
return false;
}
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