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astgen: add \u{...} unicode escape sequence handling

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Port the \u{NNNNNN} unicode escape parsing from upstream Zig's
string_literal.zig:parseEscapeSequence into both strLitAsString
(string literal decoding with UTF-8 encoding) and char_literal
(codepoint value extraction). Without this, \u escapes fell through
to the default branch which wrote a literal 'u' character, producing
incorrect ZIR string bytes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
Motiejus Jakštys
2026-02-13 22:07:23 +00:00
parent 5672cd73bc
commit 0b12e027a3
1 changed files with 68 additions and 0 deletions
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68
astgen.c
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@@ -1089,6 +1089,54 @@ static void strLitAsString(AstGenCtx* ag, uint32_t str_lit_token,
ag->string_bytes[ag->string_bytes_len++] = val;
break;
}
case 'u': {
// \u{NNNNNN} unicode escape (string_literal.zig:194-231).
// Skip past '{'.
i++;
// Parse hex digits until '}'.
uint32_t codepoint = 0;
while (i + 1 < raw_end) {
i++;
char c = source[i];
if (c >= '0' && c <= '9') {
codepoint = codepoint * 16 + (uint32_t)(c - '0');
} else if (c >= 'a' && c <= 'f') {
codepoint = codepoint * 16 + 10 + (uint32_t)(c - 'a');
} else if (c >= 'A' && c <= 'F') {
codepoint = codepoint * 16 + 10 + (uint32_t)(c - 'A');
} else {
// Must be '}', done.
break;
}
}
// Encode codepoint as UTF-8 (unicode.zig:53-82).
if (codepoint <= 0x7F) {
ag->string_bytes[ag->string_bytes_len++]
= (uint8_t)codepoint;
} else if (codepoint <= 0x7FF) {
ag->string_bytes[ag->string_bytes_len++]
= (uint8_t)(0xC0 | (codepoint >> 6));
ag->string_bytes[ag->string_bytes_len++]
= (uint8_t)(0x80 | (codepoint & 0x3F));
} else if (codepoint <= 0xFFFF) {
ag->string_bytes[ag->string_bytes_len++]
= (uint8_t)(0xE0 | (codepoint >> 12));
ag->string_bytes[ag->string_bytes_len++]
= (uint8_t)(0x80 | ((codepoint >> 6) & 0x3F));
ag->string_bytes[ag->string_bytes_len++]
= (uint8_t)(0x80 | (codepoint & 0x3F));
} else {
ag->string_bytes[ag->string_bytes_len++]
= (uint8_t)(0xF0 | (codepoint >> 18));
ag->string_bytes[ag->string_bytes_len++]
= (uint8_t)(0x80 | ((codepoint >> 12) & 0x3F));
ag->string_bytes[ag->string_bytes_len++]
= (uint8_t)(0x80 | ((codepoint >> 6) & 0x3F));
ag->string_bytes[ag->string_bytes_len++]
= (uint8_t)(0x80 | (codepoint & 0x3F));
}
break;
}
default:
ag->string_bytes[ag->string_bytes_len++] = (uint8_t)source[i];
break;
@@ -4251,6 +4299,26 @@ static uint32_t exprRl(GenZir* gz, Scope* scope, ResultLoc rl, uint32_t node) {
char_val = val;
break;
}
case 'u': {
// \u{NNNNNN} unicode escape (string_literal.zig:194-231).
// Skip past '{'.
ci++;
uint32_t codepoint = 0;
while (true) {
ci++;
char c = src[ci];
if (c >= '0' && c <= '9')
codepoint = codepoint * 16 + (uint32_t)(c - '0');
else if (c >= 'a' && c <= 'f')
codepoint = codepoint * 16 + 10 + (uint32_t)(c - 'a');
else if (c >= 'A' && c <= 'F')
codepoint = codepoint * 16 + 10 + (uint32_t)(c - 'A');
else
break; // Must be '}'.
}
char_val = codepoint;
break;
}
default:
char_val = (uint8_t)src[ci];
break;