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Some refactoring, renaming, and debug assertions for clarity and safety

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- Add more `assume()` checks in the lexer
- Replace double negative "`disable* = false`" with "`enable* = true`"
- Naming convention of "`std::deque<> *Stack`" when relying on
  `.push_front()` and `.pop_back()`
This commit is contained in:
Rangi42
2026-04-27 18:47:06 +02:00
parent 9fd0c0297f
commit 3c7488c131
5 changed files with 40 additions and 40 deletions
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docs/ARCHITECTURE.md
+1 -1
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@@ -183,7 +183,7 @@ These files have been copied ("vendored") from external authors and adapted for
- **`lexer.cpp`:**
Functions and data related to [lexing](https://en.wikipedia.org/wiki/Lexical_analysis) assembly source code into tokens, which can then be parsed.
This file maintains static `lexerState` and `lexerStateEOL` pointers to `LexerState`s from the `Context`s in `fstack.cpp`.
Each `LexerState` *owns* its `content` and its `expansions`' content. Each `Expansion` (the contents of an `{interpolation}` or macro argument) in turn *owns* its `contents`.
Each `LexerState` *owns* its `content` and its `expansionStack`'s content. Each `Expansion` (the contents of an `{interpolation}` or macro argument) in turn *owns* its `contents`.
The lexer and parser are interdependent: when the parser reaches certain tokens, it changes the lexer's mode, which affects how characters get lexed into tokens. For example, when the parser reaches a macro name, it changes the lexer to "raw" mode, which lexes the rest of the line as a sequence of string arguments to the macro.
- **`macro.cpp`:**
`MacroArgs` methods related to macro arguments. Each `MacroArgs` *references* its arguments' contents.
include/asm/lexer.hpp
+5 -5
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@@ -87,16 +87,16 @@ struct LexerState {
int lastToken;
int nextToken;
std::deque<IfStackEntry> ifStack;
std::deque<IfStackEntry> ifStack; // Front is the innermost `IF` block
bool capturing; // Whether the text being lexed should be captured
size_t captureSize; // Amount of text captured
std::shared_ptr<std::vector<char>> captureBuf; // Buffer to send the captured text to if set
bool disableExpansions;
size_t expansionScanDistance; // Max distance already scanned for expansions
bool expandStrings;
std::deque<Expansion> expansions; // Front is the innermost current expansion
bool enableExpansions;
bool enableStringExpansions;
size_t expansionScanDistance; // Max distance already scanned for expansions
std::deque<Expansion> expansionStack; // Front is the innermost current expansion
std::variant<std::monostate, ViewedContent, BufferedContent> content;
include/itertools.hpp
+1 -1
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@@ -36,7 +36,7 @@ ReversedIterable<IterableT> reversed(IterableT &&_iterable) {
// A map from `std::string` keys to `ItemT` items, iterable in the order the items were inserted.
template<typename ItemT>
class InsertionOrderedMap {
std::deque<ItemT> list;
std::deque<ItemT> list; // `deque` does not invalidate item references
std::unordered_map<std::string, size_t> map; // Indexes into `list`
public:
src/asm/fstack.cpp
+5 -5
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@@ -54,7 +54,7 @@ static std::stack<Context> contextStack;
// The first include path for `fstk_FindFile` to try is none at all
static std::vector<std::string> includePaths = {""}; // -I
static std::deque<std::string> preIncludeNames; // -P
static std::deque<std::string> preIncludeStack; // -P
static bool failedOnMissingInclude = false;
void FileStackNode::printBacktrace(uint32_t curLineNo) const {
@@ -124,9 +124,9 @@ void fstk_VerboseOutputConfig() {
}
}
// -P/--preinclude
if (!preIncludeNames.empty()) {
if (!preIncludeStack.empty()) {
fputs("\tPreincluded files:\n", stderr);
for (std::string const &name : preIncludeNames) {
for (std::string const &name : preIncludeStack) {
fprintf(stderr, "\t - %s\n", name.c_str());
}
}
@@ -168,7 +168,7 @@ void fstk_AddIncludePath(std::string const &path) {
}
void fstk_AddPreIncludeFile(std::string const &path) {
preIncludeNames.emplace_front(path);
preIncludeStack.emplace_front(path);
}
static bool isValidFilePath(std::string const &path) {
@@ -497,7 +497,7 @@ void fstk_NewRecursionDepth(size_t newDepth) {
bool fstk_Init(std::string const &mainPath) {
newFileContext(mainPath, false, true);
for (std::string const &name : preIncludeNames) {
for (std::string const &name : preIncludeStack) {
if (std::optional<std::string> fullPath = fstk_FindFile(name); fullPath) {
newFileContext(*fullPath, false, false);
} else if (fstk_FileError(name, "pre-included")) {
src/asm/lexer.cpp
+28 -28
View File
@@ -277,18 +277,18 @@ void LexerState::clear(uint32_t lineNo_) {
capturing = false;
captureBuf = nullptr;
disableExpansions = false;
enableExpansions = true;
enableStringExpansions = true;
expansionScanDistance = 0;
expandStrings = true;
expansions.clear();
expansionStack.clear();
lineNo = lineNo_; // Will be incremented at next line start
}
static void nextLine() {
// Newlines read within an expansion should not increase the line count
if (lexerState->expansions.empty()) {
if (lexerState->expansionStack.empty()) {
++lexerState->lineNo;
}
}
@@ -444,6 +444,7 @@ void BufferedContent::advance() {
}
void BufferedContent::refill() {
assume(size <= std::size(buf));
size_t target = std::size(buf) - size; // Aim: making the buf full
// Compute the index we'll start writing to
@@ -482,6 +483,7 @@ size_t BufferedContent::readMore(size_t startIndex, size_t nbChars) {
}
size += nbReadChars;
assume(size <= std::size(buf));
// `nbReadChars` cannot be negative, so it's fine to cast to `size_t`
return static_cast<size_t>(nbReadChars);
@@ -492,7 +494,7 @@ void lexer_SetMode(LexerMode mode) {
}
void lexer_ToggleStringExpansion(bool enable) {
lexerState->expandStrings = enable;
lexerState->enableStringExpansions = enable;
}
// Functions for the actual lexer to obtain characters
@@ -507,11 +509,11 @@ static void beginExpansion(std::shared_ptr<std::string> str, std::optional<std::
return;
}
lexerState->expansions.push_front({.name = name, .contents = str, .offset = 0});
lexerState->expansionStack.push_front({.name = name, .contents = str, .offset = 0});
}
void lexer_CheckRecursionDepth() {
if (lexerState->expansions.size() > options.maxRecursionDepth + 1) {
if (lexerState->expansionStack.size() > options.maxRecursionDepth + 1) {
fatal("Recursion limit (%zu) exceeded", options.maxRecursionDepth);
}
}
@@ -528,9 +530,9 @@ static int nextChar();
static uint32_t readDecimalNumber(int initial);
static uint32_t readBracketedMacroArgNum() {
bool disableExpansions = lexerState->disableExpansions;
lexerState->disableExpansions = false;
Defer restoreExpansions{[&] { lexerState->disableExpansions = disableExpansions; }};
bool enableExpansions = lexerState->enableExpansions;
lexerState->enableExpansions = true;
Defer restoreExpansions{[&] { lexerState->enableExpansions = enableExpansions; }};
int32_t num = 0;
int c = peek();
@@ -606,8 +608,7 @@ static std::shared_ptr<std::string> readMacroArg() {
error("`\\@` cannot be used outside of a macro or loop (`REPT`/`FOR` block)");
}
return str;
} else if (c == '#') {
MacroArgs *macroArgs = fstk_GetCurrentMacroArgs();
} else if (MacroArgs const *macroArgs = fstk_GetCurrentMacroArgs(); c == '#') {
if (!macroArgs) {
error("`\\#` cannot be used outside of a macro");
return nullptr;
@@ -623,7 +624,6 @@ static std::shared_ptr<std::string> readMacroArg() {
return nullptr;
}
MacroArgs *macroArgs = fstk_GetCurrentMacroArgs();
if (!macroArgs) {
error("`\\<%" PRIu32 ">` cannot be used outside of a macro", num);
return nullptr;
@@ -637,7 +637,6 @@ static std::shared_ptr<std::string> readMacroArg() {
} else {
assume(c >= '1' && c <= '9');
MacroArgs *macroArgs = fstk_GetCurrentMacroArgs();
if (!macroArgs) {
error("`\\%c` cannot be used outside of a macro", c);
return nullptr;
@@ -653,7 +652,7 @@ static std::shared_ptr<std::string> readMacroArg() {
int LexerState::peekChar() {
// This is `.peekCharAhead()` modified for zero lookahead distance
for (Expansion &exp : expansions) {
for (Expansion &exp : expansionStack) {
if (exp.offset < exp.size()) {
return static_cast<uint8_t>((*exp.contents)[exp.offset]);
}
@@ -683,7 +682,7 @@ int LexerState::peekCharAhead() {
// We only need one character of lookahead, for macro arguments
uint8_t distance = 1;
for (Expansion &exp : expansions) {
for (Expansion &exp : expansionStack) {
// An expansion that has reached its end will have `exp.offset` == `exp.size()`,
// and `.peekCharAhead()` will continue with its parent
assume(exp.offset <= exp.size());
@@ -728,7 +727,7 @@ static int peek() {
++lexerState->expansionScanDistance; // Do not consider again
if (lexerState->disableExpansions) {
if (!lexerState->enableExpansions) {
return c;
} else if (c == '\\') {
// If character is a backslash, check for a macro arg
@@ -770,15 +769,16 @@ static void shiftChar() {
++lexerState->captureSize;
}
assume(lexerState->expansionScanDistance > 0);
--lexerState->expansionScanDistance;
for (;;) {
if (!lexerState->expansions.empty()) {
if (!lexerState->expansionStack.empty()) {
// Advance within the current expansion
if (Expansion &exp = lexerState->expansions.front(); exp.advance()) {
if (Expansion &exp = lexerState->expansionStack.front(); exp.advance()) {
// When advancing would go past an expansion's end,
// move up to its parent and try again to advance
lexerState->expansions.pop_front();
lexerState->expansionStack.pop_front();
continue;
}
} else {
@@ -834,8 +834,8 @@ static void handleCRLF(int c) {
}
static auto scopedDisableExpansions() {
lexerState->disableExpansions = true;
return Defer{[&] { lexerState->disableExpansions = false; }};
lexerState->enableExpansions = false;
return Defer{[&] { lexerState->enableExpansions = true; }};
}
// "Services" provided by the lexer to the rest of the program
@@ -849,7 +849,7 @@ void lexer_TraceStringExpansions() {
return;
}
for (Expansion &exp : lexerState->expansions) {
for (Expansion &exp : lexerState->expansionStack) {
// Only print EQUS expansions, not string args
if (exp.name) {
style_Set(stderr, STYLE_CYAN, false);
@@ -1439,11 +1439,11 @@ static void appendCharInLiteral(std::string &str, int c) {
// Symbol interpolation
if (c == '{') {
// We'll be exiting the string/character scope, so re-enable expansions
lexerState->disableExpansions = false;
lexerState->enableExpansions = true;
if (auto interp = readInterpolation(0); interp.second) {
appendExpandedString(str, *interp.second);
}
lexerState->disableExpansions = true;
lexerState->enableExpansions = false;
return;
}
@@ -1956,7 +1956,7 @@ static Token yylex_NORMAL() {
std::string const &identifier = std::get<std::string>(token.value);
// Raw symbols and local symbols cannot be string expansions
if (!raw && token.type == T_(SYMBOL) && lexerState->expandStrings) {
if (!raw && token.type == T_(SYMBOL) && lexerState->enableStringExpansions) {
// Attempt string expansion
if (Symbol const *sym = sym_FindExactSymbol(identifier);
sym && sym->type == SYM_EQUS) {
@@ -2162,7 +2162,7 @@ finish: // Can't `break` out of a nested `for`-`switch`
// tokens that would change how these constructs were captured or skipped, if
// they had been produced during the capture/skip non-evaluating phase.
static Token skipToLeadingKeyword() {
assume(lexerState->disableExpansions);
assume(!lexerState->enableExpansions);
for (;;) {
if (lexerState->atLineStart) {
@@ -2321,7 +2321,7 @@ static Capture makeCapture(char const *name, CallbackFnT callback) {
.lineNo = lexer_GetLineNo(), .span = {.ptr = nullptr, .size = 0}
};
if (std::holds_alternative<ViewedContent>(lexerState->content)
&& lexerState->expansions.empty()) {
&& lexerState->expansionStack.empty()) {
auto &view = std::get<ViewedContent>(lexerState->content);
capture.span.ptr = view.makeSharedContentPtr();
} else {