Encapsulate access to sectionList and currentSection

include/asm/section.hpp

@@ -5,6 +5,7 @@
 
 #include <deque>
 #include <memory>
+#include <optional>
 #include <stdint.h>
 #include <string>
 #include <unordered_map>
@@ -40,6 +41,7 @@ struct Section {
 	std::deque<Patch> patches;
 	std::vector<uint8_t> data;
 
+	uint32_t getID() const; // ID of the section in the object file (`UINT32_MAX` if none)
 	bool isSizeKnown() const;
 };
 
@@ -49,8 +51,8 @@ struct SectionSpec {
 	uint16_t alignOfs;
 };
 
-extern std::deque<Section> sectionList;
+size_t sect_CountSections();
-extern Section *currentSection;
+void sect_ForEach(void (*callback)(Section &));
 
 Section *sect_FindSectionByName(std::string const &name);
 void sect_NewSection(
@@ -73,6 +75,10 @@ void sect_CheckLoadClosed();
 Section *sect_GetSymbolSection();
 uint32_t sect_GetSymbolOffset();
 uint32_t sect_GetOutputOffset();
+std::optional<uint32_t> sect_GetOutputBank();
+
+Patch *sect_AddOutputPatch();
+
 uint32_t sect_GetAlignBytes(uint8_t alignment, uint16_t offset);
 void sect_AlignPC(uint8_t alignment, uint16_t offset);
 

src/asm/output.cpp

@@ -60,29 +60,13 @@ void out_RegisterNode(std::shared_ptr<FileStackNode> node) {
 	}
 }
 
-// Return a section's ID, or UINT32_MAX if the section does not exist
-static uint32_t getSectIDIfAny(Section *sect) {
-	if (!sect) {
-		return UINT32_MAX;
-	}
-
-	// Section fragments share the same name but have different IDs, so search by identity
-	if (auto search =
-	        std::find_if(RANGE(sectionList), [&sect](Section const &s) { return &s == sect; });
-	    search != sectionList.end()) {
-		return static_cast<uint32_t>(std::distance(sectionList.begin(), search));
-	}
-
-	fatal("Unknown section '%s'", sect->name.c_str()); // LCOV_EXCL_LINE
-}
-
 static void writePatch(Patch const &patch, FILE *file) {
 	assume(patch.src->ID != UINT32_MAX);
 
 	putLong(patch.src->ID, file);
 	putLong(patch.lineNo, file);
 	putLong(patch.offset, file);
-	putLong(getSectIDIfAny(patch.pcSection), file);
+	putLong(patch.pcSection ? patch.pcSection->getID() : UINT32_MAX, file);
 	putLong(patch.pcOffset, file);
 	putc(patch.type, file);
 	putLong(patch.rpn.size(), file);
@@ -126,10 +110,12 @@ static void writeSymbol(Symbol const &sym, FILE *file) {
 	} else {
 		assume(sym.src->ID != UINT32_MAX);
 
+		Section *symSection = sym.getSection();
+
 		putc(sym.isExported ? SYMTYPE_EXPORT : SYMTYPE_LOCAL, file);
 		putLong(sym.src->ID, file);
 		putLong(sym.fileLine, file);
-		putLong(getSectIDIfAny(sym.getSection()), file);
+		putLong(symSection ? symSection->getID() : UINT32_MAX, file);
 		putLong(sym.getOutputValue(), file);
 	}
 }
@@ -259,7 +245,8 @@ static void initPatch(Patch &patch, uint32_t type, Expression const &expr, uint3
 
 void out_CreatePatch(uint32_t type, Expression const &expr, uint32_t ofs, uint32_t pcShift) {
 	// Add the patch to the list
-	Patch &patch = currentSection->patches.emplace_front();
+	assume(sect_GetOutputBank().has_value());
+	Patch &patch = *sect_AddOutputPatch();
 
 	initPatch(patch, type, expr, ofs);
 
@@ -305,7 +292,7 @@ void out_WriteObject() {
 		return;
 	}
 
-	FILE *file;
+	static FILE *file; // `static` so `sect_ForEach` callback can see it
 	if (options.objectFileName != "-") {
 		file = fopen(options.objectFileName.c_str(), "wb");
 	} else {
@@ -329,7 +316,7 @@ void out_WriteObject() {
 	putLong(RGBDS_OBJECT_REV, file);
 
 	putLong(objectSymbols.size(), file);
-	putLong(sectionList.size(), file);
+	putLong(sect_CountSections(), file);
 
 	putLong(fileStackNodes.size(), file);
 	for (auto it = fileStackNodes.begin(); it != fileStackNodes.end(); ++it) {
@@ -345,9 +332,7 @@ void out_WriteObject() {
 		writeSymbol(*sym, file);
 	}
 
-	for (Section const &sect : sectionList) {
+	sect_ForEach([](Section &sect) { writeSection(sect, file); });
-		writeSection(sect, file);
-	}
 
 	putLong(assertions.size(), file);
 

src/asm/rpn.cpp

@@ -4,6 +4,7 @@
 
 #include <inttypes.h>
 #include <limits.h>
+#include <optional>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -102,15 +103,15 @@ void Expression::makeBankSymbol(std::string const &symName) {
 	clear();
 	if (Symbol const *sym = sym_FindScopedSymbol(symName); sym_IsPC(sym)) {
 		// The @ symbol is treated differently.
-		if (!currentSection) {
+		if (std::optional<uint32_t> outputBank = sect_GetOutputBank(); !outputBank) {
 			error("PC has no bank outside of a section");
 			data = 1;
-		} else if (currentSection->bank == UINT32_MAX) {
+		} else if (*outputBank == UINT32_MAX) {
 			data = "Current section's bank is not known";
 
 			*reserveSpace(1) = RPN_BANK_SELF;
 		} else {
-			data = static_cast<int32_t>(currentSection->bank);
+			data = static_cast<int32_t>(*outputBank);
 		}
 		return;
 	} else if (sym && !sym->isLabel()) {

src/asm/section.cpp

@@ -5,7 +5,6 @@
 #include <algorithm>
 #include <errno.h>
 #include <inttypes.h>
-#include <optional>
 #include <stack>
 #include <stdio.h>
 #include <stdlib.h>
@@ -38,8 +37,8 @@ struct SectionStackEntry {
 	std::stack<UnionStackEntry> unionStack;
 };
 
-Section *currentSection = nullptr;
+static Section *currentSection = nullptr;
-std::deque<Section> sectionList;
+static std::deque<Section> sectionList;
 static std::unordered_map<std::string, size_t> sectionMap; // Indexes into `sectionList`
 
 static uint32_t curOffset; // Offset into the current section (see `sect_GetSymbolOffset`)
@@ -78,6 +77,16 @@ static bool requireCodeSection() {
 	return false;
 }
 
+size_t sect_CountSections() {
+	return sectionList.size();
+}
+
+void sect_ForEach(void (*callback)(Section &)) {
+	for (Section &sect : sectionList) {
+		callback(sect);
+	}
+}
+
 void sect_CheckSizes() {
 	for (Section const &sect : sectionList) {
 		if (uint32_t maxSize = sectionTypeInfo[sect.type].size; sect.size > maxSize) {
@@ -440,6 +449,16 @@ static void changeSection() {
 	sym_ResetCurrentLabelScopes();
 }
 
+uint32_t Section::getID() const {
+	// Section fragments share the same name but have different IDs, so search by identity
+	if (auto search =
+	        std::find_if(RANGE(sectionList), [this](Section const &s) { return &s == this; });
+	    search != sectionList.end()) {
+		return static_cast<uint32_t>(std::distance(sectionList.begin(), search));
+	}
+	return UINT32_MAX; // LCOV_EXCL_LINE
+}
+
 bool Section::isSizeKnown() const {
 	// SECTION UNION and SECTION FRAGMENT can still grow
 	if (modifier != SECTION_NORMAL) {
@@ -555,6 +574,14 @@ uint32_t sect_GetOutputOffset() {
 	return curOffset + loadOffset;
 }
 
+std::optional<uint32_t> sect_GetOutputBank() {
+	return currentSection ? std::optional<uint32_t>(currentSection->bank) : std::nullopt;
+}
+
+Patch *sect_AddOutputPatch() {
+	return currentSection ? &currentSection->patches.emplace_front() : nullptr;
+}
+
 // Returns how many bytes need outputting for the specified alignment and offset to succeed
 uint32_t sect_GetAlignBytes(uint8_t alignment, uint16_t offset) {
 	Section *sect = sect_GetSymbolSection();