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Eliminate isAtEOF by changing yylex control flow

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`yylex` calls `yywrap` at the beginning of the next call, after it
has set `lexerState->lastToken` to `T_EOB`.
This commit is contained in:
Rangi
2021-04-20 10:26:51 -04:00
committed by Eldred Habert
parent a727a0f81f
commit 8230e8165c
1 changed files with 9 additions and 13 deletions
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22
src/asm/lexer.c
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@@ -354,7 +354,6 @@ struct LexerState {
uint32_t colNo;
int lastToken;
int nextToken;
bool isAtEOF;
struct IfStack *ifStack;
@@ -379,7 +378,6 @@ static void initState(struct LexerState *state)
state->atLineStart = true; /* yylex() will init colNo due to this */
state->lastToken = T_EOF;
state->nextToken = 0;
state->isAtEOF = false;
state->ifStack = NULL;
@@ -571,7 +569,7 @@ void lexer_DeleteState(struct LexerState *state)
// that lexer states lifetimes are always properly managed, since they're handled solely
// by the fstack... with *one* exception.
// Assume a context is pushed on top of the fstack, and the corresponding lexer state gets
// scheduled at EOF; `lexerStateAtEOL` thus becomes a (weak) ref to that lexer state...
// scheduled at EOF; `lexerStateEOL` thus becomes a (weak) ref to that lexer state...
// It has been possible, due to a bug, that the corresponding fstack context gets popped
// before EOL, deleting the associated state... but it would still be switched to at EOL.
// This assertion checks that this doesn't happen again.
@@ -2280,13 +2278,17 @@ finish:
int yylex(void)
{
if (lexerStateEOL) {
if (lexerState->atLineStart && lexerStateEOL) {
lexer_SetState(lexerStateEOL);
lexerStateEOL = NULL;
}
/* `lexer_SetState` updates `lexerState`, so check for EOF after it */
if (lexerState->isAtEOF)
return T_EOF;
if (lexerState->lastToken == T_EOB) {
if (yywrap()) {
dbgPrint("Reached end of input.\n");
return T_EOF;
}
}
if (lexerState->atLineStart) {
/* Newlines read within an expansion should not increase the line count */
if (!lexerState->expansions)
@@ -2303,16 +2305,10 @@ int yylex(void)
int token = lexerModeFuncs[lexerState->mode]();
if (token == T_EOF) {
/* Try to switch to new buffer; if it succeeds, scan again */
dbgPrint("Reached EOB!\n");
/* Captures end at their buffer's boundary no matter what */
if (!lexerState->capturing) {
if (yywrap()) {
dbgPrint("Reached end of input.\n");
lexerState->isAtEOF = true;
}
if (!lexerState->capturing)
token = T_EOB;
}
}
lexerState->lastToken = token;
lexerState->atLineStart = token == T_NEWLINE || token == T_EOB;