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

contrib/zsh_compl/_rgbasm

@@ -42,7 +42,7 @@ local args=(
 	'(-v --verbose)'{-v,--verbose}'[Enable verbose output]'
 	-w'[Disable all warnings]'
 
-	'(-B --backtrace)'{-B,--backtrace}'+[Set backtrace depth or style]:depth:'
+	'(-B --backtrace)'{-B,--backtrace}'+[Set backtrace depth or style]:param:'
 	'(-b --binary-digits)'{-b,--binary-digits}'+[Change chars for binary constants]:digit spec:'
 	--color'[Whether to use color in output]:color:(auto always never)'
 	'*'{-D,--define}'+[Define a string symbol]:name + value (default 1):'

contrib/zsh_compl/_rgblink

@@ -28,7 +28,7 @@ local args=(
 	'(-w --wramx)'{-w,--wramx}'[Disable WRAM banking]'
 	'(-x --nopad)'{-x,--nopad}'[Disable padding the end of the final file]'
 
-	'(-B --backtrace)'{-B,--backtrace}'+[Set backtrace depth or style]:depth:'
+	'(-B --backtrace)'{-B,--backtrace}'+[Set backtrace depth or style]:param:'
 	--color'[Whether to use color in output]:color:(auto always never)'
 	'(-l --linkerscript)'{-l,--linkerscript}"+[Use a linker script]:linker script:_files -g '*.link'"
 	'(-M --no-sym-in-map)'{-M,--no-sym-in-map}'[Do not output symbol names in map file]'

include/asm/fstack.hpp

@@ -24,6 +24,7 @@ struct FileStackNode {
 	    std::string            // NODE_FILE, NODE_MACRO
 	    >
 	    data;
+	bool isQuiet; // Whether to omit this node from error reporting
 
 	std::shared_ptr<FileStackNode> parent; // Pointer to parent node, for error reporting
 	// Line at which the parent context was exited
@@ -40,8 +41,12 @@ struct FileStackNode {
 	std::string &name() { return std::get<std::string>(data); }
 	std::string const &name() const { return std::get<std::string>(data); }
 
-	FileStackNode(FileStackNodeType type_, std::variant<std::vector<uint32_t>, std::string> data_)
-	    : type(type_), data(data_) {}
+	FileStackNode(
+	    FileStackNodeType type_,
+	    std::variant<std::vector<uint32_t>, std::string> data_,
+	    bool isQuiet_
+	)
+	    : type(type_), data(data_), isQuiet(isQuiet_) {}
 
 	void printBacktrace(uint32_t curLineNo) const;
 };
@@ -62,16 +67,19 @@ bool fstk_FileError(std::string const &path, char const *functionName);
 bool fstk_FailedOnMissingInclude();
 
 bool yywrap();
-bool fstk_RunInclude(std::string const &path);
-void fstk_RunMacro(std::string const &macroName, std::shared_ptr<MacroArgs> macroArgs);
-void fstk_RunRept(uint32_t count, int32_t reptLineNo, ContentSpan const &span);
+bool fstk_RunInclude(std::string const &path, bool isQuiet);
+void fstk_RunMacro(
+    std::string const &macroName, std::shared_ptr<MacroArgs> macroArgs, bool isQuiet
+);
+void fstk_RunRept(uint32_t count, int32_t reptLineNo, ContentSpan const &span, bool isQuiet);
 void fstk_RunFor(
     std::string const &symName,
     int32_t start,
     int32_t stop,
     int32_t step,
     int32_t reptLineNo,
-    ContentSpan const &span
+    ContentSpan const &span,
+    bool isQuiet
 );
 bool fstk_Break();
 

include/asm/symbol.hpp

@@ -30,8 +30,9 @@ bool sym_IsPC(Symbol const *sym); // Forward declaration for `getSection`
 struct Symbol {
 	std::string name;
 	SymbolType type;
-	bool isExported; // Whether the symbol is to be exported
-	bool isBuiltin;  // Whether the symbol is a built-in
+	bool isBuiltin;
+	bool isExported; // Not relevant for SYM_MACRO or SYM_EQUS
+	bool isQuiet;    // Only relevant for SYM_MACRO
 	Section *section;
 	std::shared_ptr<FileStackNode> src; // Where the symbol was defined
 	uint32_t fileLine;                  // Line where the symbol was defined
@@ -88,7 +89,9 @@ Symbol *sym_FindScopedSymbol(std::string const &symName);
 // Find a scoped symbol by name; do not return `@` or `_NARG` when they have no value
 Symbol *sym_FindScopedValidSymbol(std::string const &symName);
 Symbol const *sym_GetPC();
-Symbol *sym_AddMacro(std::string const &symName, int32_t defLineNo, ContentSpan const &span);
+Symbol *sym_AddMacro(
+    std::string const &symName, int32_t defLineNo, ContentSpan const &span, bool isQuiet
+);
 Symbol *sym_Ref(std::string const &symName);
 Symbol *sym_AddString(std::string const &symName, std::shared_ptr<std::string> value);
 Symbol *sym_RedefString(std::string const &symName, std::shared_ptr<std::string> value);

include/backtrace.hpp

@@ -11,58 +11,74 @@
 
 #include "style.hpp"
 
-static constexpr uint64_t TRACE_COLLAPSE = UINT64_MAX;
+struct Tracing {
+	uint64_t depth = 0;
+	bool collapse = false;
+	bool loud = false;
+};
 
-extern uint64_t traceDepth;
+extern Tracing tracing;
 
 bool trace_ParseTraceDepth(char const *arg);
 
 template<typename T, typename M, typename N>
 void trace_PrintBacktrace(std::vector<T> const &stack, M getName, N getLineNo) {
-	auto printLocation = [&](T const &item) {
+	size_t n = stack.size();
+	if (n == 0) {
+		return; // LCOV_EXCL_LINE
+	}
+
+	auto printLocation = [&](size_t i) {
+		T const &item = stack[n - i - 1];
+		style_Reset(stderr);
+		if (!tracing.collapse) {
+			fputs("   ", stderr); // Just three spaces; the fourth will be printed next
+		}
+		fprintf(stderr, " %s ", i == 0 ? "at" : "<-");
 		style_Set(stderr, STYLE_CYAN, true);
 		fputs(getName(item), stderr);
 		style_Set(stderr, STYLE_CYAN, false);
 		fprintf(stderr, "(%" PRIu32 ")", getLineNo(item));
+		if (!tracing.collapse) {
+			putc('\n', stderr);
+		}
 	};
 
-	size_t n = stack.size();
-
-	if (traceDepth == TRACE_COLLAPSE) {
+	if (tracing.collapse) {
 		fputs("   ", stderr); // Just three spaces; the fourth will be handled by the loop
-		for (size_t i = 0; i < n; ++i) {
-			style_Reset(stderr);
-			fprintf(stderr, " %s ", i == 0 ? "at" : "<-");
-			printLocation(stack[n - i - 1]);
 	}
-		putc('\n', stderr);
-	} else if (traceDepth == 0 || static_cast<size_t>(traceDepth) >= n) {
+
+	if (tracing.depth == 0 || static_cast<size_t>(tracing.depth) >= n) {
 		for (size_t i = 0; i < n; ++i) {
-			style_Reset(stderr);
-			fprintf(stderr, "    %s ", i == 0 ? "at" : "<-");
-			printLocation(stack[n - i - 1]);
-			putc('\n', stderr);
+			printLocation(i);
 		}
 	} else {
-		size_t last = traceDepth / 2;
-		size_t first = traceDepth - last;
-		size_t skipped = n - traceDepth;
+		size_t last = tracing.depth / 2;
+		size_t first = tracing.depth - last;
+		size_t skipped = n - tracing.depth;
 		for (size_t i = 0; i < first; ++i) {
-			style_Reset(stderr);
-			fprintf(stderr, "    %s ", i == 0 ? "at" : "<-");
-			printLocation(stack[n - i - 1]);
-			putc('\n', stderr);
+			printLocation(i);
 		}
 		style_Reset(stderr);
-		fprintf(stderr, "    ...%zu more%s\n", skipped, last ? "..." : "");
-		for (size_t i = n - last; i < n; ++i) {
-			style_Reset(stderr);
-			fputs("    <- ", stderr);
-			printLocation(stack[n - i - 1]);
+
+		if (tracing.collapse) {
+			fputs(" <-", stderr);
+		} else {
+			fputs("   ", stderr); // Just three spaces; the fourth will be printed next
+		}
+		fprintf(stderr, " ...%zu more%s", skipped, last ? "..." : "");
+		if (!tracing.collapse) {
 			putc('\n', stderr);
 		}
+
+		for (size_t i = n - last; i < n; ++i) {
+			printLocation(i);
+		}
 	}
 
+	if (tracing.collapse) {
+		putc('\n', stderr);
+	}
 	style_Reset(stderr);
 }
 

include/link/fstack.hpp

@@ -19,6 +19,7 @@ struct FileStackNode {
 	    std::string            // NODE_FILE, NODE_MACRO
 	    >
 	    data;
+	bool isQuiet; // Whether to omit this node from error reporting
 
 	FileStackNode *parent;
 	// Line at which the parent context was exited; meaningless for the root level

include/linkdefs.hpp

@@ -9,7 +9,7 @@
 #include "helpers.hpp" // assume
 
 #define RGBDS_OBJECT_VERSION_STRING "RGB9"
-#define RGBDS_OBJECT_REV            12U
+#define RGBDS_OBJECT_REV            13U
 
 enum AssertionType { ASSERT_WARN, ASSERT_ERROR, ASSERT_FATAL };
 
@@ -78,12 +78,18 @@ enum SectionType {
 	SECTTYPE_INVALID
 };
 
+static constexpr uint8_t SECTTYPE_TYPE_MASK = 0b111;
+static constexpr uint8_t SECTTYPE_UNION_BIT = 7;
+static constexpr uint8_t SECTTYPE_FRAGMENT_BIT = 6;
+
 enum FileStackNodeType {
 	NODE_REPT,
 	NODE_FILE,
 	NODE_MACRO,
 };
 
+static constexpr uint8_t FSTACKNODE_QUIET_BIT = 7;
+
 // Nont-`const` members may be patched in RGBLINK depending on CLI flags
 extern struct SectionTypeInfo {
 	std::string const name;

man/rgbasm.1

@@ -9,7 +9,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl EhVvw
-.Op Fl B Ar depth
+.Op Fl B Ar param
 .Op Fl b Ar chars
 .Op Fl \-color Ar when
 .Op Fl D Ar name Ns Op = Ns Ar value
@@ -53,15 +53,29 @@ is invalid because it could also be
 .Fl \-version .
 The arguments are as follows:
 .Bl -tag -width Ds
-.It Fl B Ar depth , Fl \-backtrace Ar depth
-Specifies the maximum depth for which
-.Nm
-will print location backtraces for warnings or errors.
-Deeper backtraces than that will be abbreviated.
-.Fl B Ar 0
-allows unlimited-depth backtraces.
-.Fl B Ar collapse
-will print the entire location trace on one line.
+.It Fl B Ar param , Fl \-backtrace Ar param
+Configures how location backtraces are printed if warnings or errors occur.
+This flag may be specified multiple times with different parameters that combine meaningfully.
+If
+.Ar param
+is a positive number, it specifies the maximum backtrace depth, abbreviating deeper ones.
+Other valid parameter values are the following:
+.Bl -tag -width Ds
+.It Cm 0
+Do not limit the maximum backtrace depth; this is the default.
+.It Cm all
+Force all locations to be printed, even "quiet" ones (see
+.Dq Excluding locations from backtraces
+in
+.Xr rgbasm 5
+for details).
+.It Cm no-all
+Do not print "quieted" locations in backtraces; this is the default.
+.It Cm collapse
+Print all locations on one line.
+.It Cm no-collapse
+Print one location per line; this is the default.
+.El
 .It Fl b Ar chars , Fl \-binary-digits Ar chars
 Allow two characters to be used for binary constants in addition to the default
 .Sq 0

man/rgbasm.5

@@ -1681,7 +1681,8 @@ $ rgbasm -o a.o a.asm
 $ rgbasm -o b.o b.asm
 $ rgbasm -o c.o c.asm
 $ rgblink a.o b.o c.o
-error: c.asm(2): Unknown symbol "LabelA"
+error: Undefined symbol "LabelA"
+    at c.asm(2)
 Linking failed with 1 error
 .Ed
 .Pp
@@ -2516,6 +2517,68 @@ PUSHO b.X, g.oOX
     DW `..ooOOXX
 POPO
 .Ed
+.Ss Excluding locations from backtraces
+Errors and warnings print
+.Em backtraces
+showing the location in the source file where the problem occurred, tracing the origin of the problem even through a chain of
+.Ic REPT ,
+.Ic FOR ,
+.Ic MACRO ,
+and
+.Ic INCLUDE
+locations.
+Sometimes there are locations you would like to ignore; for example, a common utility macro when you only care about the line where the macro is used, or an
+.Ic INCLUDE
+file that only serves to include other files and is just filler in the backtrace.
+.Pp
+In those cases, you can
+.Em silence
+a location with a question mark
+.Sq \&?
+after the token: all of the locations created by a
+.Sq REPT? ,
+.Sq FOR? ,
+or
+.Sq MACRO?
+will not be printed, and any location created by a
+.Sq INCLUDE? ,
+or a macro invocation whose name is immediately followed by a
+.Sq \&? ,
+will not be printed.
+For example, if this were assembled as
+.Ql example.asm :
+.Bd -literal -offset indent
+MACRO lb
+    assert -128 <= (\e2) && (\e2) < 256, "\e2 is not a byte"
+    assert -128 <= (\e3) && (\e3) < 256, "\e3 is not a byte"
+    ld \e1, (LOW(\e2) << 8) | LOW(\e3)
+ENDM
+SECTION "Code", ROM0
+    lb hl, $123, $45
+.Ed
+.Pp
+This would print an error backtrace:
+.Bd -literal -offset indent
+error: Assertion failed: $123 is not a byte
+    at example.asm::lb(2)
+    <- example.asm(7)
+.Ed
+.Pp
+But if
+.Ql MACRO
+were changed to
+.Ql MACRO? ,
+or
+.Ql lb hl
+were changed to
+.Ql lb? hl ,
+then the error backtrace would not mention the location within the
+.Ql lb
+macro:
+.Bd -literal -offset indent
+error: Assertion failed: $123 is not a byte
+    at example.asm(7)
+.Ed
 .Sh SEE ALSO
 .Xr rgbasm 1 ,
 .Xr rgblink 1 ,

man/rgbds.5

@@ -79,12 +79,16 @@ order, meaning the node with ID 0 is the last one in the list!
 .It Cm LONG Ar ParentLineNo
 Line at which the parent node's context was exited; meaningless for the root node.
 .It Cm BYTE Ar Type
+Bits 0\(en6 indicate the node's type:
 .Bl -column "Value" -compact
 .It Sy Value Ta Sy Meaning
 .It 0 Ta REPT node
 .It 1 Ta File node
 .It 2 Ta Macro node
 .El
+.Pp
+Bit\ 7 being set means that the node is "quieted"
+.Pq see Do Excluding locations from backtraces Dc in Xr rgbasm 5 .
 .It Cm IF Ar Type No \(!= 0
 If the node is not a REPT node...
 .Pp

man/rgblink.1

@@ -9,7 +9,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl dhMtVvwx
-.Op Fl B Ar depth
+.Op Fl B Ar param
 .Op Fl \-color Ar when
 .Op Fl l Ar linker_script
 .Op Fl m Ar map_file
@@ -65,15 +65,29 @@ is invalid because it could also be
 .Fl \-version .
 The arguments are as follows:
 .Bl -tag -width Ds
-.It Fl B Ar depth , Fl \-backtrace Ar depth
-Specifies the maximum depth for which
-.Nm
-will print location backtraces for warnings or errors.
-Deeper backtraces than that will be abbreviated.
-.Fl B Ar 0
-allows unlimited-depth backtraces.
-.Fl B Ar collapse
-will print the entire location trace on one line.
+.It Fl B Ar param , Fl \-backtrace Ar param
+Configures how location backtraces are printed if warnings or errors occur.
+This flag may be specified multiple times with different parameters that combine meaningfully.
+If
+.Ar param
+is a positive number, it specifies the maximum backtrace depth, abbreviating deeper ones.
+Other valid parameter values are the following:
+.Bl -tag -width Ds
+.It Cm 0
+Do not limit the maximum backtrace depth; this is the default.
+.It Cm all
+Force all locations to be printed, even "quiet" ones (see
+.Dq Excluding locations from backtraces
+in
+.Xr rgbasm 5
+for details).
+.It Cm no-all
+Do not print "quieted" locations in backtraces; this is the default.
+.It Cm collapse
+Print all locations on one line.
+.It Cm no-collapse
+Print one location per line; this is the default.
+.El
 .It Fl \-color Ar when
 Specify when to highlight warning and error messages with color:
 .Ql always ,

src/asm/fstack.cpp

@@ -63,6 +63,16 @@ static std::string reptChain(FileStackNode const &node) {
 using TraceNode = std::pair<std::string, uint32_t>;
 
 static std::vector<TraceNode> backtrace(FileStackNode const &node, uint32_t curLineNo) {
+	if (node.isQuiet && !tracing.loud) {
+		if (node.parent) {
+			// Quiet REPT nodes will pass their interior line number up to their parent,
+			// which is more precise than the parent's own line number (since that will be
+			// the line number of the "REPT?" or "FOR?" itself).
+			return backtrace(*node.parent, node.type == NODE_REPT ? curLineNo : node.lineNo);
+		}
+		return {}; // LCOV_EXCL_LINE
+	}
+
 	if (!node.parent) {
 		assume(node.type != NODE_REPT && std::holds_alternative<std::string>(node.data));
 		return {
@@ -244,14 +254,14 @@ static void checkRecursionDepth() {
 	}
 }
 
-static void newFileContext(std::string const &filePath, bool updateStateNow) {
+static void newFileContext(std::string const &filePath, bool isQuiet, bool updateStateNow) {
 	checkRecursionDepth();
 
 	std::shared_ptr<std::string> uniqueIDStr = nullptr;
 	std::shared_ptr<MacroArgs> macroArgs = nullptr;
 
 	auto fileInfo =
-	    std::make_shared<FileStackNode>(NODE_FILE, filePath == "-" ? "<stdin>" : filePath);
+	    std::make_shared<FileStackNode>(NODE_FILE, filePath == "-" ? "<stdin>" : filePath, isQuiet);
 	if (!contextStack.empty()) {
 		Context &oldContext = contextStack.top();
 		fileInfo->parent = oldContext.fileInfo;
@@ -269,7 +279,8 @@ static void newFileContext(std::string const &filePath, bool updateStateNow) {
 	context.lexerState.setFileAsNextState(filePath, updateStateNow);
 }
 
-static void newMacroContext(Symbol const &macro, std::shared_ptr<MacroArgs> macroArgs) {
+static void
+    newMacroContext(Symbol const &macro, std::shared_ptr<MacroArgs> macroArgs, bool isQuiet) {
 	checkRecursionDepth();
 
 	Context &oldContext = contextStack.top();
@@ -287,7 +298,7 @@ static void newMacroContext(Symbol const &macro, std::shared_ptr<MacroArgs> macr
 	fileInfoName.append("::");
 	fileInfoName.append(macro.name);
 
-	auto fileInfo = std::make_shared<FileStackNode>(NODE_MACRO, fileInfoName);
+	auto fileInfo = std::make_shared<FileStackNode>(NODE_MACRO, fileInfoName, isQuiet);
 	assume(!contextStack.empty()); // The top level context cannot be a MACRO
 	fileInfo->parent = oldContext.fileInfo;
 	fileInfo->lineNo = lexer_GetLineNo();
@@ -301,7 +312,8 @@ static void newMacroContext(Symbol const &macro, std::shared_ptr<MacroArgs> macr
 	context.lexerState.setViewAsNextState("MACRO", macro.getMacro(), macro.fileLine);
 }
 
-static Context &newReptContext(int32_t reptLineNo, ContentSpan const &span, uint32_t count) {
+static Context &
+    newReptContext(int32_t reptLineNo, ContentSpan const &span, uint32_t count, bool isQuiet) {
 	checkRecursionDepth();
 
 	Context &oldContext = contextStack.top();
@@ -312,7 +324,7 @@ static Context &newReptContext(int32_t reptLineNo, ContentSpan const &span, uint
 		fileInfoIters.insert(fileInfoIters.end(), RANGE(oldContext.fileInfo->iters()));
 	}
 
-	auto fileInfo = std::make_shared<FileStackNode>(NODE_REPT, fileInfoIters);
+	auto fileInfo = std::make_shared<FileStackNode>(NODE_REPT, fileInfoIters, isQuiet);
 	assume(!contextStack.empty()); // The top level context cannot be a REPT
 	fileInfo->parent = oldContext.fileInfo;
 	fileInfo->lineNo = reptLineNo;
@@ -356,15 +368,17 @@ bool fstk_FailedOnMissingInclude() {
 	return failedOnMissingInclude;
 }
 
-bool fstk_RunInclude(std::string const &path) {
+bool fstk_RunInclude(std::string const &path, bool isQuiet) {
 	if (std::optional<std::string> fullPath = fstk_FindFile(path); fullPath) {
-		newFileContext(*fullPath, false);
+		newFileContext(*fullPath, isQuiet, false);
 		return false;
 	}
 	return fstk_FileError(path, "INCLUDE");
 }
 
-void fstk_RunMacro(std::string const &macroName, std::shared_ptr<MacroArgs> macroArgs) {
+void fstk_RunMacro(
+    std::string const &macroName, std::shared_ptr<MacroArgs> macroArgs, bool isQuiet
+) {
 	Symbol *macro = sym_FindExactSymbol(macroName);
 
 	if (!macro) {
@@ -380,15 +394,15 @@ void fstk_RunMacro(std::string const &macroName, std::shared_ptr<MacroArgs> macr
 		return;
 	}
 
-	newMacroContext(*macro, macroArgs);
+	newMacroContext(*macro, macroArgs, isQuiet || macro->isQuiet);
 }
 
-void fstk_RunRept(uint32_t count, int32_t reptLineNo, ContentSpan const &span) {
+void fstk_RunRept(uint32_t count, int32_t reptLineNo, ContentSpan const &span, bool isQuiet) {
 	if (count == 0) {
 		return;
 	}
 
-	newReptContext(reptLineNo, span, count);
+	newReptContext(reptLineNo, span, count, isQuiet);
 }
 
 void fstk_RunFor(
@@ -397,7 +411,8 @@ void fstk_RunFor(
     int32_t stop,
     int32_t step,
     int32_t reptLineNo,
-    ContentSpan const &span
+    ContentSpan const &span,
+    bool isQuiet
 ) {
 	if (Symbol *sym = sym_AddVar(symName, start); sym->type != SYM_VAR) {
 		return;
@@ -422,7 +437,7 @@ void fstk_RunFor(
 		return;
 	}
 
-	Context &context = newReptContext(reptLineNo, span, count);
+	Context &context = newReptContext(reptLineNo, span, count, isQuiet);
 	context.isForLoop = true;
 	context.forValue = start;
 	context.forStep = step;
@@ -447,11 +462,11 @@ void fstk_NewRecursionDepth(size_t newDepth) {
 }
 
 void fstk_Init(std::string const &mainPath) {
-	newFileContext(mainPath, true);
+	newFileContext(mainPath, false, true);
 
 	for (std::string const &name : preIncludeNames) {
 		if (std::optional<std::string> fullPath = fstk_FindFile(name); fullPath) {
-			newFileContext(*fullPath, false);
+			newFileContext(*fullPath, false, false);
 		} else {
 			error("Error reading pre-included file \"%s\": %s", name.c_str(), strerror(errno));
 		}

src/asm/lexer.cpp

@@ -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;

src/asm/output.cpp

@@ -83,10 +83,10 @@ static void writeSection(Section const &sect, FILE *file) {
 
 	putLong(sect.size, file);
 
+	assume((sect.type & SECTTYPE_TYPE_MASK) == sect.type);
 	bool isUnion = sect.modifier == SECTION_UNION;
 	bool isFragment = sect.modifier == SECTION_FRAGMENT;
-
-	putc(sect.type | isUnion << 7 | isFragment << 6, file);
+	putc(sect.type | isUnion << SECTTYPE_UNION_BIT | isFragment << SECTTYPE_FRAGMENT_BIT, file);
 
 	putLong(sect.org, file);
 	putLong(sect.bank, file);
@@ -268,7 +268,9 @@ static void writeAssert(Assertion const &assert, FILE *file) {
 static void writeFileStackNode(FileStackNode const &node, FILE *file) {
 	putLong(node.parent ? node.parent->ID : UINT32_MAX, file);
 	putLong(node.lineNo, file);
-	putc(node.type, file);
+
+	putc(node.type | node.isQuiet << FSTACKNODE_QUIET_BIT, file);
+
 	if (node.type != NODE_REPT) {
 		putString(node.name(), file);
 	} else {

src/asm/parser.y

@@ -98,6 +98,7 @@
 %token LBRACK "[" RBRACK "]"
 %token LBRACKS "[[" RBRACKS "]]"
 %token LPAREN "(" RPAREN ")"
+%token QUESTIONMARK "?"
 
 // Arithmetic operators
 %token OP_ADD "+" OP_SUB "-"
@@ -322,6 +323,7 @@
 %token <std::string> LABEL "label"
 %token <std::string> LOCAL "local label"
 %token <std::string> ANON "anonymous label"
+%token <std::string> QMACRO "quiet macro"
 
 /******************** Data types ********************/
 
@@ -398,6 +400,7 @@
 %type <SectionType> sect_type
 %type <StrFmtArgList> strfmt_args
 %type <StrFmtArgList> strfmt_va_args
+%type <bool> maybe_quiet
 
 %%
 
@@ -544,7 +547,13 @@ macro:
 		// Parsing 'macro_args' will restore the lexer's normal mode
 		lexer_SetMode(LEXER_RAW);
 	} macro_args {
-		fstk_RunMacro($1, $3);
+		fstk_RunMacro($1, $3, false);
+	}
+	| QMACRO {
+		// Parsing 'macro_args' will restore the lexer's normal mode
+		lexer_SetMode(LEXER_RAW);
+	} macro_args {
+		fstk_RunMacro($1, $3, true);
 	}
 ;
 
@@ -780,10 +789,19 @@ load:
 	}
 ;
 
+maybe_quiet:
+	%empty {
+		$$ = false;
+	}
+	| QUESTIONMARK {
+		$$ = true;
+	}
+;
+
 rept:
-	POP_REPT uconst NEWLINE capture_rept endofline {
-		if ($4.span.ptr) {
-			fstk_RunRept($2, $4.lineNo, $4.span);
+	POP_REPT maybe_quiet uconst NEWLINE capture_rept endofline {
+		if ($5.span.ptr) {
+			fstk_RunRept($3, $5.lineNo, $5.span, $2);
 		}
 	}
 ;
@@ -791,11 +809,11 @@ rept:
 for:
 	POP_FOR {
 		lexer_ToggleStringExpansion(false);
-	} SYMBOL {
+	} maybe_quiet SYMBOL {
 		lexer_ToggleStringExpansion(true);
 	} COMMA for_args NEWLINE capture_rept endofline {
-		if ($8.span.ptr) {
-			fstk_RunFor($3, $6.start, $6.stop, $6.step, $8.lineNo, $8.span);
+		if ($9.span.ptr) {
+			fstk_RunFor($4, $7.start, $7.stop, $7.step, $9.lineNo, $9.span, $3);
 		}
 	}
 ;
@@ -835,11 +853,11 @@ break:
 def_macro:
 	POP_MACRO {
 		lexer_ToggleStringExpansion(false);
-	} SYMBOL {
+	} maybe_quiet SYMBOL {
 		lexer_ToggleStringExpansion(true);
 	} NEWLINE capture_macro endofline {
-		if ($6.span.ptr) {
-			sym_AddMacro($3, $6.lineNo, $6.span);
+		if ($7.span.ptr) {
+			sym_AddMacro($4, $7.lineNo, $7.span, $3);
 		}
 	}
 ;
@@ -1002,8 +1020,8 @@ export_def:
 ;
 
 include:
-	label POP_INCLUDE string endofline {
-		if (fstk_RunInclude($3)) {
+	label POP_INCLUDE maybe_quiet string endofline {
+		if (fstk_RunInclude($4, $3)) {
 			YYACCEPT;
 		}
 	}

src/asm/symbol.cpp

@@ -205,8 +205,9 @@ static Symbol &createSymbol(std::string const &symName) {
 	Symbol &sym = symbols[symName];
 
 	sym.name = symName;
-	sym.isExported = false;
 	sym.isBuiltin = false;
+	sym.isExported = false;
+	sym.isQuiet = false;
 	sym.section = nullptr;
 	sym.src = fstk_GetFileStack();
 	sym.fileLine = sym.src ? lexer_GetLineNo() : 0;
@@ -616,7 +617,9 @@ void sym_Export(std::string const &symName) {
 	sym->isExported = true;
 }
 
-Symbol *sym_AddMacro(std::string const &symName, int32_t defLineNo, ContentSpan const &span) {
+Symbol *sym_AddMacro(
+    std::string const &symName, int32_t defLineNo, ContentSpan const &span, bool isQuiet
+) {
 	Symbol *sym = createNonrelocSymbol(symName, false);
 
 	if (!sym) {
@@ -625,6 +628,7 @@ Symbol *sym_AddMacro(std::string const &symName, int32_t defLineNo, ContentSpan
 
 	sym->type = SYM_MACRO;
 	sym->data = span;
+	sym->isQuiet = isQuiet;
 
 	sym->src = fstk_GetFileStack();
 	// The symbol is created at the line after the `ENDM`,

src/backtrace.cpp

@@ -6,16 +6,24 @@
 
 #include "platform.hpp" // strcasecmp
 
-uint64_t traceDepth = 0;
+Tracing tracing;
 
 bool trace_ParseTraceDepth(char const *arg) {
 	if (!strcasecmp(arg, "collapse")) {
-		traceDepth = TRACE_COLLAPSE;
+		tracing.collapse = true;
 		return true;
-	}
-
+	} else if (!strcasecmp(arg, "no-collapse")) {
+		tracing.collapse = false;
+		return true;
+	} else if (!strcasecmp(arg, "all")) {
+		tracing.loud = true;
+		return true;
+	} else if (!strcasecmp(arg, "no-all")) {
+		tracing.loud = false;
+		return true;
+	} else {
 		char *endptr;
-	traceDepth = strtoul(arg, &endptr, 0);
-
-	return arg[0] != '\0' && *endptr == '\0' && traceDepth != TRACE_COLLAPSE;
+		tracing.depth = strtoul(arg, &endptr, 0);
+		return arg[0] != '\0' && *endptr == '\0';
+	}
 }

src/link/fstack.cpp

@@ -9,6 +9,16 @@
 using TraceNode = std::pair<std::string, uint32_t>;
 
 static std::vector<TraceNode> backtrace(FileStackNode const &node, uint32_t curLineNo) {
+	if (node.isQuiet && !tracing.loud) {
+		if (node.parent) {
+			// Quiet REPT nodes will pass their interior line number up to their parent,
+			// which is more precise than the parent's own line number (since that will be
+			// the line number of the "REPT?" or "FOR?" itself).
+			return backtrace(*node.parent, node.type == NODE_REPT ? curLineNo : node.lineNo);
+		}
+		return {}; // LCOV_EXCL_LINE
+	}
+
 	if (!node.parent) {
 		assume(node.type != NODE_REPT && std::holds_alternative<std::string>(node.data));
 		return {

src/link/object.cpp

@@ -105,14 +105,12 @@ static void readFileStackNode(
 	tryReadLong(
 	    node.lineNo, file, "%s: Cannot read node #%" PRIu32 "'s line number: %s", fileName, nodeID
 	);
-	tryGetc(
-	    FileStackNodeType,
-	    node.type,
-	    file,
-	    "%s: Cannot read node #%" PRIu32 "'s type: %s",
-	    fileName,
-	    nodeID
-	);
+
+	uint8_t type;
+	tryGetc(uint8_t, type, file, "%s: Cannot read node #%" PRIu32 "'s type: %s", fileName, nodeID);
+	node.type = static_cast<FileStackNodeType>(type & ~(1 << FSTACKNODE_QUIET_BIT));
+	node.isQuiet = (type & (1 << FSTACKNODE_QUIET_BIT)) != 0;
+
 	switch (node.type) {
 	case NODE_FILE:
 	case NODE_MACRO:
@@ -318,14 +316,14 @@ static void readSection(
 	tryGetc(
 	    uint8_t, byte, file, "%s: Cannot read \"%s\"'s type: %s", fileName, section.name.c_str()
 	);
-	if (uint8_t type = byte & 0x3F; type >= SECTTYPE_INVALID) {
+	if (uint8_t type = byte & SECTTYPE_TYPE_MASK; type >= SECTTYPE_INVALID) {
 		fatal("\"%s\" has unknown section type 0x%02x", section.name.c_str(), type);
 	} else {
 		section.type = SectionType(type);
 	}
-	if (byte >> 7) {
+	if (byte & (1 << SECTTYPE_UNION_BIT)) {
 		section.modifier = SECTION_UNION;
-	} else if (byte >> 6) {
+	} else if (byte & (1 << SECTTYPE_FRAGMENT_BIT)) {
 		section.modifier = SECTION_FRAGMENT;
 	} else {
 		section.modifier = SECTION_NORMAL;
@@ -458,6 +456,7 @@ void obj_ReadFile(char const *fileName, unsigned int fileID) {
 		nodes[fileID].push_back({
 		    .type = NODE_FILE,
 		    .data = std::variant<std::monostate, std::vector<uint32_t>, std::string>(fileName),
+		    .isQuiet = false,
 		    .parent = nullptr,
 		    .lineNo = 0,
 		});

test/asm/backtrace-depth.flags

@@ -1 +1 @@
--B 5
+-B 5 -B no-collapse

test/asm/expansion-diagnostics.flags

@@ -1 +1 @@
--B 0
+-B no-collapse

test/asm/garbage_sequence.asm

@@ -1,5 +1,5 @@
 assert 1 +# 1 == 2
-assert 2 ?<EFBFBD>* 2 == 4
-assert 3 **?<EFBFBD>?##?? 3 == 27
+assert 2 #<EFBFBD>* 2 == 4
+assert 3 **#<EFBFBD>}<EFBFBD># 3 == 27
 charmap "x", 4
 assert 4 <<#<EFBFBD>'x' == 64

test/asm/garbage_sequence.err

@@ -1,13 +1,11 @@
 error: Invalid character '#'
     at garbage_sequence.asm(1)
-error: Invalid characters '?', 0xFF (is the file UTF-8?)
+error: Invalid characters '#', 0xFF (is the file UTF-8?)
     at garbage_sequence.asm(2)
-error: Invalid characters '?', 0xFF, '?' (is the file UTF-8?)
+error: Invalid characters '#', 0xFF, '}', 0xFF (is the file UTF-8?)
     at garbage_sequence.asm(3)
 error: Invalid character '#'
     at garbage_sequence.asm(3)
-error: Invalid characters '#', '?', '?'
-    at garbage_sequence.asm(3)
 error: Invalid characters '#', 0xFF (is the file UTF-8?)
     at garbage_sequence.asm(5)
-Assembly aborted with 6 errors!
+Assembly aborted with 5 errors!

test/asm/lex-label.err

@@ -1,10 +1,10 @@
 error: syntax error, unexpected label, expecting symbol
     at lex-label.asm(1)
-error: syntax error, unexpected label, expecting symbol
+error: syntax error, unexpected label, expecting ? or symbol
     at lex-label.asm(3)
 error: syntax error, unexpected ENDM
     at lex-label.asm(4)
-error: syntax error, unexpected label, expecting symbol
+error: syntax error, unexpected label, expecting ? or symbol
     at lex-label.asm(6)
 error: syntax error, unexpected ENDR
     at lex-label.asm(7)

test/asm/loud-backtrace.asm

@@ -0,0 +1,20 @@
+macro mac
+	warn "from macro"
+endm
+mac ; normal
+
+macro? quiet
+	warn "from quiet macro"
+endm
+quiet
+rept? 1
+	warn "from quiet rept"
+endr
+for? x, 1
+	warn "from quiet for (x={d:x})"
+endr
+include? "loud-backtrace.inc"
+macro loud
+	warn "from loud macro"
+endm
+mac?

test/asm/loud-backtrace.err

@@ -0,0 +1,12 @@
+warning: from macro [-Wuser]
+    at loud-backtrace.asm::mac(2) <- loud-backtrace.asm(4)
+warning: from quiet macro [-Wuser]
+    at loud-backtrace.asm::quiet(7) <- loud-backtrace.asm(9)
+warning: from quiet rept [-Wuser]
+    at loud-backtrace.asm::REPT~1(11) <- loud-backtrace.asm(10)
+warning: from quiet for (x=0) [-Wuser]
+    at loud-backtrace.asm::REPT~1(14) <- loud-backtrace.asm(13)
+warning: from quiet include [-Wuser]
+    at loud-backtrace.inc(1) <- loud-backtrace.asm(16)
+warning: from macro [-Wuser]
+    at loud-backtrace.asm::mac(2) <- loud-backtrace.asm(20)

test/asm/loud-backtrace.flags

@@ -0,0 +1 @@
+-B all

test/asm/loud-backtrace.inc

@@ -0,0 +1 @@
+warn "from quiet include"

test/asm/quiet-backtrace.asm

@@ -0,0 +1,20 @@
+macro mac
+	warn "from macro"
+endm
+mac ; normal
+
+macro? quiet
+	warn "from quiet macro"
+endm
+quiet
+rept? 1
+	warn "from quiet rept"
+endr
+for? x, 1
+	warn "from quiet for (x={d:x})"
+endr
+include? "quiet-backtrace.inc"
+macro loud
+	warn "from loud macro"
+endm
+mac?

test/asm/quiet-backtrace.err

@@ -0,0 +1,12 @@
+warning: from macro [-Wuser]
+    at quiet-backtrace.asm::mac(2) <- quiet-backtrace.asm(4)
+warning: from quiet macro [-Wuser]
+    at quiet-backtrace.asm(9)
+warning: from quiet rept [-Wuser]
+    at quiet-backtrace.asm(11)
+warning: from quiet for (x=0) [-Wuser]
+    at quiet-backtrace.asm(14)
+warning: from quiet include [-Wuser]
+    at quiet-backtrace.asm(16)
+warning: from macro [-Wuser]
+    at quiet-backtrace.asm(20)

test/asm/quiet-backtrace.inc

@@ -0,0 +1 @@
+warn "from quiet include"

test/asm/rept-macro-fstack-trace.flags

@@ -1 +1 @@
--B 0
+-B no-collapse