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Implement ? suffix to "quiet" a context and exclude it from backtraces (#1800)

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This commit is contained in:
Rangi
2025-08-18 21:34:58 -04:00
committed by GitHub
parent 77a105e189
commit b7e0783ae7
32 changed files with 392 additions and 139 deletions
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31
src/asm/lexer.cpp
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@@ -1561,9 +1561,8 @@ static bool isGarbageCharacter(int c) {
if (isWhitespace(c)) {
return false;
}
// Printable characters which are nevertheless garbage: braces should have been interpolated,
// and question mark is unused
if (c == '{' || c == '}' || c == '?') {
// Printable characters which are nevertheless garbage: braces should have been interpolated
if (c == '{' || c == '}') {
return true;
}
// All other printable characters are not garbage (i.e. `yylex_NORMAL` handles them), and
@@ -1614,6 +1613,9 @@ static Token yylex_NORMAL() {
case '~':
return Token(T_(OP_NOT));
case '?':
return Token(T_(QUESTIONMARK));
case '@': {
std::string symName("@");
return Token(T_(SYMBOL), symName);
@@ -1926,22 +1928,23 @@ static Token yylex_NORMAL() {
}
}
// We need to distinguish between label definitions (which start with `LABEL`) and
// macro invocations (which start with `SYMBOL`).
// We need to distinguish between:
// - label definitions (which are followed by a ':' and use the token `LABEL`)
// - quiet macro invocations (which are followed by a '?' and use the token `QMACRO`)
// - regular macro invocations (which use the token `SYMBOL`)
//
// If we had one `IDENTIFIER` token, the parser would need to perform "lookahead" to
// determine which rule applies. But since macros need to enter "raw" mode to parse
// their arguments, which may not even be valid tokens in "normal" mode, we cannot use
// lookahead to check for the presence of a `COLON`.
// lookahead to check for the presence of a `COLON` or `QUESTIONMARK`.
//
// Instead, we have separate `SYMBOL` and `LABEL` tokens, lexing as a `LABEL` if a ':'
// character *immediately* follows the identifier. Thus, "Label:" and "mac:" are treated
// as label definitions, but "Label :" and "mac :" are treated as macro invocations.
//
// The alternative would be a "lexer hack" like C, where identifiers would lex as a
// `SYMBOL` if they are already defined, otherwise as a `LABEL`.
if (token.type == T_(SYMBOL) && peek() == ':') {
token.type = T_(LABEL);
// Instead, we have separate `SYMBOL`, `LABEL`, and `QMACRO` tokens, and decide which
// one to lex depending on the character *immediately* following the identifier.
// Thus "name:" is a label definition, and "name?" is a quiet macro invocation, but
// "name :" and "name ?" and just "name" are all regular macro invocations.
if (token.type == T_(SYMBOL)) {
c = peek();
token.type = c == ':' ? T_(LABEL) : c == '?' ? T_(QMACRO) : T_(SYMBOL);
}
return token;