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llvm-project/clang/Sema/SemaExpr.cpp

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//===--- SemaExpr.cpp - Semantic Analysis for Expressions -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements semantic analysis for expressions.
//
//===----------------------------------------------------------------------===//
#include "Sema.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/Expr.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
using namespace llvm;
using namespace clang;
/// HexDigitValue - Return the value of the specified hex digit, or -1 if it's
/// not valid.
static int HexDigitValue(char C) {
if (C >= '0' && C <= '9') return C-'0';
if (C >= 'a' && C <= 'f') return C-'a'+10;
if (C >= 'A' && C <= 'F') return C-'A'+10;
return -1;
}
/// ParseStringExpr - The specified tokens were lexed as pasted string
/// fragments (e.g. "foo" "bar" L"baz"). The result string has to handle string
/// concatenation ([C99 5.1.1.2, translation phase #6]), so it may come from
/// multiple tokens. However, the common case is that StringToks points to one
/// string.
///
Action::ExprResult
Sema::ParseStringExpr(const LexerToken *StringToks, unsigned NumStringToks) {
assert(NumStringToks && "Must have at least one string!");
// Scan all of the string portions, remember the max individual token length,
// computing a bound on the concatenated string length, and see whether any
// piece is a wide-string. If any of the string portions is a wide-string
// literal, the result is a wide-string literal [C99 6.4.5p4].
unsigned MaxTokenLength = StringToks[0].getLength();
unsigned SizeBound = StringToks[0].getLength()-2; // -2 for "".
bool AnyWide = StringToks[0].getKind() == tok::wide_string_literal;
// The common case is that there is only one string fragment.
for (unsigned i = 1; i != NumStringToks; ++i) {
// The string could be shorter than this if it needs cleaning, but this is a
// reasonable bound, which is all we need.
SizeBound += StringToks[i].getLength()-2; // -2 for "".
// Remember maximum string piece length.
if (StringToks[i].getLength() > MaxTokenLength)
MaxTokenLength = StringToks[i].getLength();
// Remember if we see any wide strings.
AnyWide |= StringToks[i].getKind() == tok::wide_string_literal;
}
// Include space for the null terminator.
++SizeBound;
// TODO: K&R warning: "traditional C rejects string constant concatenation"
// Get the width in bytes of wchar_t. If no wchar_t strings are used, do not
// query the target. As such, wchar_tByteWidth is only valid if AnyWide=true.
unsigned wchar_tByteWidth = ~0U;
if (AnyWide)
wchar_tByteWidth =Context.Target.getWCharWidth(StringToks[0].getLocation());
// The output buffer size needs to be large enough to hold wide characters.
// This is a worst-case assumption which basically corresponds to L"" "long".
if (AnyWide)
SizeBound *= wchar_tByteWidth;
// Create a temporary buffer to hold the result string data.
SmallString<512> ResultBuf;
ResultBuf.resize(SizeBound);
// Likewise, but for each string piece.
SmallString<512> TokenBuf;
TokenBuf.resize(MaxTokenLength);
// Loop over all the strings, getting their spelling, and expanding them to
// wide strings as appropriate.
char *ResultPtr = &ResultBuf[0]; // Next byte to fill in.
for (unsigned i = 0, e = NumStringToks; i != e; ++i) {
const char *ThisTokBuf = &TokenBuf[0];
// Get the spelling of the token, which eliminates trigraphs, etc. We know
// that ThisTokBuf points to a buffer that is big enough for the whole token
// and 'spelled' tokens can only shrink.
unsigned ThisTokLen = Context.PP.getSpelling(StringToks[i], ThisTokBuf);
const char *ThisTokEnd = ThisTokBuf+ThisTokLen-1; // Skip end quote.
// TODO: Input character set mapping support.
// Skip L marker for wide strings.
if (ThisTokBuf[0] == 'L') ++ThisTokBuf;
assert(ThisTokBuf[0] == '"' && "Expected quote, lexer broken?");
++ThisTokBuf;
while (ThisTokBuf != ThisTokEnd) {
// Is this a span of non-escape characters?
if (ThisTokBuf[0] != '\\') {
const char *InStart = ThisTokBuf;
do {
++ThisTokBuf;
} while (ThisTokBuf != ThisTokEnd && ThisTokBuf[0] != '\\');
// Copy the character span over.
unsigned Len = ThisTokBuf-InStart;
if (!AnyWide) {
memcpy(ResultPtr, InStart, Len);
ResultPtr += Len;
} else {
// Note: our internal rep of wide char tokens is always little-endian.
for (; Len; --Len, ++InStart) {
*ResultPtr++ = InStart[0];
// Add zeros at the end.
for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i)
*ResultPtr++ = 0;
}
}
continue;
}
// Otherwise, this is an escape character. Skip the '\' char.
++ThisTokBuf;
// We know that this character can't be off the end of the buffer, because
// that would have been \", which would not have been the end of string.
unsigned ResultChar = *ThisTokBuf++;
switch (ResultChar) {
// These map to themselves.
case '\\': case '\'': case '"': case '?': break;
// These have fixed mappings.
case 'a':
// TODO: K&R: the meaning of '\\a' is different in traditional C
ResultChar = 7;
break;
case 'b':
ResultChar = 8;
break;
case 'e':
Diag(StringToks[i].getLocation(), diag::ext_nonstandard_escape, "e");
ResultChar = 27;
break;
case 'f':
ResultChar = 12;
break;
case 'n':
ResultChar = 10;
break;
case 'r':
ResultChar = 13;
break;
case 't':
ResultChar = 9;
break;
case 'v':
ResultChar = 11;
break;
//case 'u': case 'U': // FIXME: UCNs.
case 'x': // Hex escape.
if (ThisTokBuf == ThisTokEnd ||
(ResultChar = HexDigitValue(*ThisTokBuf)) == ~0U) {
Diag(StringToks[i].getLocation(), diag::err_hex_escape_no_digits);
ResultChar = 0;
break;
}
++ThisTokBuf; // Consumed one hex digit.
assert(0 && "hex escape: unimp!");
break;
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
// Octal escapes.
assert(0 && "octal escape: unimp!");
break;
// Otherwise, these are not valid escapes.
case '(': case '{': case '[': case '%':
// GCC accepts these as extensions. We warn about them as such though.
if (!Context.PP.getLangOptions().NoExtensions) {
Diag(StringToks[i].getLocation(), diag::ext_nonstandard_escape,
std::string()+(char)ResultChar);
break;
}
// FALL THROUGH.
default:
if (isgraph(ThisTokBuf[0])) {
Diag(StringToks[i].getLocation(), diag::ext_unknown_escape,
std::string()+(char)ResultChar);
} else {
Diag(StringToks[i].getLocation(), diag::ext_unknown_escape,
"x"+utohexstr(ResultChar));
}
}
// Note: our internal rep of wide char tokens is always little-endian.
*ResultPtr++ = ResultChar & 0xFF;
if (AnyWide) {
for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i)
*ResultPtr++ = ResultChar >> i*8;
}
}
}
// Add zero terminator.
*ResultPtr = 0;
if (AnyWide) {
for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i)
*ResultPtr++ = 0;
}
SmallVector<SourceLocation, 4> StringTokLocs;
for (unsigned i = 0; i != NumStringToks; ++i)
StringTokLocs.push_back(StringToks[i].getLocation());
// FIXME: use factory.
// Pass &StringTokLocs[0], StringTokLocs.size() to factory!
return new StringExpr(&ResultBuf[0], ResultPtr-&ResultBuf[0], AnyWide);
}
/// ParseIdentifierExpr - The parser read an identifier in expression context,
/// validate it per-C99 6.5.1. HasTrailingLParen indicates whether this
/// identifier is used in an function call context.
Sema::ExprResult Sema::ParseIdentifierExpr(Scope *S, SourceLocation Loc,
IdentifierInfo &II,
bool HasTrailingLParen) {
// Could be enum-constant or decl.
Decl *D = II.getFETokenInfo<Decl>();
if (D == 0) {
// FIXME: check to see if this is a use of a builtin. By handling builtins
// here, we can avoid having to preload tons of decls for functions.
// Otherwise, this is an imlicitly declared function reference (legal in
// C90, extension in C99).
if (HasTrailingLParen &&
// Not in C++.
!getLangOptions().CPlusPlus) {
D = ImplicitlyDefineFunction(Loc, II, S);
} else {
// If this name wasn't predeclared and if this is not a function call,
// diagnose the problem.
Diag(Loc, diag::err_undeclared_var_use, II.getName());
return true;
}
}
if (isa<TypeDecl>(D)) {
Diag(Loc, diag::err_unexpected_typedef, II.getName());
return true;
}
return new DeclRefExpr(D);
}
Sema::ExprResult Sema::ParseSimplePrimaryExpr(SourceLocation Loc,
tok::TokenKind Kind) {
switch (Kind) {
default:
assert(0 && "Unknown simple primary expr!");
case tok::char_constant: // constant: character-constant
// TODO: MOVE this to be some other callback.
case tok::kw___func__: // primary-expression: __func__ [C99 6.4.2.2]
case tok::kw___FUNCTION__: // primary-expression: __FUNCTION__ [GNU]
case tok::kw___PRETTY_FUNCTION__: // primary-expression: __P..Y_F..N__ [GNU]
return 0;
}
}
Sema::ExprResult Sema::ParseIntegerConstant(SourceLocation Loc) {
return new IntegerConstant();
}
Sema::ExprResult Sema::ParseFloatingConstant(SourceLocation Loc) {
return new FloatingConstant();
}
Action::ExprResult Sema::ParseParenExpr(SourceLocation L, SourceLocation R,
ExprTy *Val) {
return Val;
}
// Unary Operators. 'Tok' is the token for the operator.
Action::ExprResult Sema::ParseUnaryOp(SourceLocation OpLoc, tok::TokenKind Op,
ExprTy *Input) {
UnaryOperator::Opcode Opc;
switch (Op) {
default: assert(0 && "Unknown unary op!");
case tok::plusplus: Opc = UnaryOperator::PreInc; break;
case tok::minusminus: Opc = UnaryOperator::PreDec; break;
case tok::amp: Opc = UnaryOperator::AddrOf; break;
case tok::star: Opc = UnaryOperator::Deref; break;
case tok::plus: Opc = UnaryOperator::Plus; break;
case tok::minus: Opc = UnaryOperator::Minus; break;
case tok::tilde: Opc = UnaryOperator::Not; break;
case tok::exclaim: Opc = UnaryOperator::LNot; break;
case tok::kw_sizeof: Opc = UnaryOperator::SizeOf; break;
case tok::kw___alignof: Opc = UnaryOperator::AlignOf; break;
case tok::kw___real: Opc = UnaryOperator::Real; break;
case tok::kw___imag: Opc = UnaryOperator::Imag; break;
case tok::ampamp: Opc = UnaryOperator::AddrLabel; break;
case tok::kw___extension__:
return Input;
//Opc = UnaryOperator::Extension;
//break;
}
return new UnaryOperator((Expr*)Input, Opc);
}
Action::ExprResult Sema::
ParseSizeOfAlignOfTypeExpr(SourceLocation OpLoc, bool isSizeof,
SourceLocation LParenLoc, TypeTy *Ty,
SourceLocation RParenLoc) {
// If error parsing type, ignore.
if (Ty == 0) return true;
// Verify that this is a valid expression.
TypeRef ArgTy = TypeRef::getFromOpaquePtr(Ty);
if (isa<FunctionType>(ArgTy) && isSizeof) {
// alignof(function) is allowed.
Diag(OpLoc, diag::ext_sizeof_function_type);
return new IntegerConstant(/*1*/);
} else if (ArgTy->isVoidType()) {
Diag(OpLoc, diag::ext_sizeof_void_type, isSizeof ? "sizeof" : "__alignof");
} else if (ArgTy->isIncompleteType()) {
std::string TypeName;
ArgTy->getAsString(TypeName);
Diag(OpLoc, isSizeof ? diag::err_sizeof_incomplete_type :
diag::err_alignof_incomplete_type, TypeName);
return new IntegerConstant(/*0*/);
}
return new SizeOfAlignOfTypeExpr(isSizeof, ArgTy);
}
Action::ExprResult Sema::ParsePostfixUnaryOp(SourceLocation OpLoc,
tok::TokenKind Kind,
ExprTy *Input) {
UnaryOperator::Opcode Opc;
switch (Kind) {
default: assert(0 && "Unknown unary op!");
case tok::plusplus: Opc = UnaryOperator::PostInc; break;
case tok::minusminus: Opc = UnaryOperator::PostDec; break;
}
return new UnaryOperator((Expr*)Input, Opc);
}
Action::ExprResult Sema::
ParseArraySubscriptExpr(ExprTy *Base, SourceLocation LLoc,
ExprTy *Idx, SourceLocation RLoc) {
return new ArraySubscriptExpr((Expr*)Base, (Expr*)Idx);
}
Action::ExprResult Sema::
ParseMemberReferenceExpr(ExprTy *Base, SourceLocation OpLoc,
tok::TokenKind OpKind, SourceLocation MemberLoc,
IdentifierInfo &Member) {
Decl *MemberDecl = 0;
// TODO: Look up MemberDecl.
return new MemberExpr((Expr*)Base, OpKind == tok::arrow, MemberDecl);
}
/// ParseCallExpr - Handle a call to Fn with the specified array of arguments.
/// This provides the location of the left/right parens and a list of comma
/// locations.
Action::ExprResult Sema::
ParseCallExpr(ExprTy *Fn, SourceLocation LParenLoc,
ExprTy **Args, unsigned NumArgs,
SourceLocation *CommaLocs, SourceLocation RParenLoc) {
return new CallExpr((Expr*)Fn, (Expr**)Args, NumArgs);
}
Action::ExprResult Sema::
ParseCastExpr(SourceLocation LParenLoc, TypeTy *Ty,
SourceLocation RParenLoc, ExprTy *Op) {
// If error parsing type, ignore.
if (Ty == 0) return true;
return new CastExpr(TypeRef::getFromOpaquePtr(Ty), (Expr*)Op);
}
// Binary Operators. 'Tok' is the token for the operator.
Action::ExprResult Sema::ParseBinOp(SourceLocation TokLoc, tok::TokenKind Kind,
ExprTy *LHS, ExprTy *RHS) {
BinaryOperator::Opcode Opc;
switch (Kind) {
default: assert(0 && "Unknown binop!");
case tok::star: Opc = BinaryOperator::Mul; break;
case tok::slash: Opc = BinaryOperator::Div; break;
case tok::percent: Opc = BinaryOperator::Rem; break;
case tok::plus: Opc = BinaryOperator::Add; break;
case tok::minus: Opc = BinaryOperator::Sub; break;
case tok::lessless: Opc = BinaryOperator::Shl; break;
case tok::greatergreater: Opc = BinaryOperator::Shr; break;
case tok::lessequal: Opc = BinaryOperator::LE; break;
case tok::less: Opc = BinaryOperator::LT; break;
case tok::greaterequal: Opc = BinaryOperator::GE; break;
case tok::greater: Opc = BinaryOperator::GT; break;
case tok::exclaimequal: Opc = BinaryOperator::NE; break;
case tok::equalequal: Opc = BinaryOperator::EQ; break;
case tok::amp: Opc = BinaryOperator::And; break;
case tok::caret: Opc = BinaryOperator::Xor; break;
case tok::pipe: Opc = BinaryOperator::Or; break;
case tok::ampamp: Opc = BinaryOperator::LAnd; break;
case tok::pipepipe: Opc = BinaryOperator::LOr; break;
case tok::equal: Opc = BinaryOperator::Assign; break;
case tok::starequal: Opc = BinaryOperator::MulAssign; break;
case tok::slashequal: Opc = BinaryOperator::DivAssign; break;
case tok::percentequal: Opc = BinaryOperator::RemAssign; break;
case tok::plusequal: Opc = BinaryOperator::AddAssign; break;
case tok::minusequal: Opc = BinaryOperator::SubAssign; break;
case tok::lesslessequal: Opc = BinaryOperator::ShlAssign; break;
case tok::greatergreaterequal: Opc = BinaryOperator::ShrAssign; break;
case tok::ampequal: Opc = BinaryOperator::AndAssign; break;
case tok::caretequal: Opc = BinaryOperator::XorAssign; break;
case tok::pipeequal: Opc = BinaryOperator::OrAssign; break;
case tok::comma: Opc = BinaryOperator::Comma; break;
}
return new BinaryOperator((Expr*)LHS, (Expr*)RHS, Opc);
}
/// ParseConditionalOp - Parse a ?: operation. Note that 'LHS' may be null
/// in the case of a the GNU conditional expr extension.
Action::ExprResult Sema::ParseConditionalOp(SourceLocation QuestionLoc,
SourceLocation ColonLoc,
ExprTy *Cond, ExprTy *LHS,
ExprTy *RHS) {
return new ConditionalOperator((Expr*)Cond, (Expr*)LHS, (Expr*)RHS);
}
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