Commit b3cd38ea4a

Andrew Kelley <andrew@ziglang.org>
2022-10-25 01:48:15
link: add an explicit error set for flush() and flushModule()
This makes it easier to understand how control flow should happen in various cases; already just by doing this it is revealed that UndefinedSymbol and UndefinedSymbolReference should be merged, and that MissingMainEntrypoint should be removed in favor of the ErrorFlags mechanism thath we already have for missing the main entrypoint. The main motivation for this change, however, is preventing a compile error when there is conditional compilation inside linker implementations, causing the flush() error set to depend on compilation options. With this change, the error set is fixed, and, notably, the `-Donly-c` flag no longer has compilation errors due to this error set.
1 parent 4f04759
src/link/MachO/dead_strip.zig
@@ -17,7 +17,7 @@ const N_DEAD = @import("zld.zig").N_DEAD;
 
 const AtomTable = std.AutoHashMap(AtomIndex, void);
 
-pub fn gcAtoms(zld: *Zld, reverse_lookups: [][]u32) !void {
+pub fn gcAtoms(zld: *Zld, reverse_lookups: [][]u32) Allocator.Error!void {
     const gpa = zld.gpa;
 
     var arena = std.heap.ArenaAllocator.init(gpa);
@@ -30,8 +30,8 @@ pub fn gcAtoms(zld: *Zld, reverse_lookups: [][]u32) !void {
     try alive.ensureTotalCapacity(@intCast(u32, zld.atoms.items.len));
 
     try collectRoots(zld, &roots);
-    try mark(zld, roots, &alive, reverse_lookups);
-    try prune(zld, alive);
+    mark(zld, roots, &alive, reverse_lookups);
+    prune(zld, alive);
 }
 
 fn collectRoots(zld: *Zld, roots: *AtomTable) !void {
@@ -133,7 +133,7 @@ fn markLive(
     atom_index: AtomIndex,
     alive: *AtomTable,
     reverse_lookups: [][]u32,
-) anyerror!void {
+) void {
     if (alive.contains(atom_index)) return;
 
     const atom = zld.getAtom(atom_index);
@@ -171,7 +171,7 @@ fn markLive(
                 const other_atom = zld.getAtom(other_atom_index);
                 const other_sym = zld.getSymbol(other_atom.getSymbolWithLoc());
                 if (other_sym.n_sect == sect_id) {
-                    try markLive(zld, other_atom_index, alive, reverse_lookups);
+                    markLive(zld, other_atom_index, alive, reverse_lookups);
                 }
             }
             continue;
@@ -194,11 +194,11 @@ fn markLive(
             zld.getAtom(target_atom_index).file,
         });
 
-        try markLive(zld, target_atom_index, alive, reverse_lookups);
+        markLive(zld, target_atom_index, alive, reverse_lookups);
     }
 }
 
-fn refersLive(zld: *Zld, atom_index: AtomIndex, alive: AtomTable, reverse_lookups: [][]u32) !bool {
+fn refersLive(zld: *Zld, atom_index: AtomIndex, alive: AtomTable, reverse_lookups: [][]u32) bool {
     const atom = zld.getAtom(atom_index);
     const sym_loc = atom.getSymbolWithLoc();
 
@@ -240,10 +240,10 @@ fn refersLive(zld: *Zld, atom_index: AtomIndex, alive: AtomTable, reverse_lookup
     return false;
 }
 
-fn mark(zld: *Zld, roots: AtomTable, alive: *AtomTable, reverse_lookups: [][]u32) !void {
+fn mark(zld: *Zld, roots: AtomTable, alive: *AtomTable, reverse_lookups: [][]u32) void {
     var it = roots.keyIterator();
     while (it.next()) |root| {
-        try markLive(zld, root.*, alive, reverse_lookups);
+        markLive(zld, root.*, alive, reverse_lookups);
     }
 
     var loop: bool = true;
@@ -265,8 +265,8 @@ fn mark(zld: *Zld, roots: AtomTable, alive: *AtomTable, reverse_lookups: [][]u32
                 const source_sect = object.getSourceSection(sect_id);
 
                 if (source_sect.isDontDeadStripIfReferencesLive()) {
-                    if (try refersLive(zld, atom_index, alive.*, reverse_lookups)) {
-                        try markLive(zld, atom_index, alive, reverse_lookups);
+                    if (refersLive(zld, atom_index, alive.*, reverse_lookups)) {
+                        markLive(zld, atom_index, alive, reverse_lookups);
                         loop = true;
                     }
                 }
@@ -275,7 +275,7 @@ fn mark(zld: *Zld, roots: AtomTable, alive: *AtomTable, reverse_lookups: [][]u32
     }
 }
 
-fn prune(zld: *Zld, alive: AtomTable) !void {
+fn prune(zld: *Zld, alive: AtomTable) void {
     log.debug("pruning dead atoms", .{});
     for (zld.objects.items) |*object| {
         var i: usize = 0;
src/link/MachO/zld.zig
@@ -3735,7 +3735,7 @@ const SymbolResolver = struct {
     unresolved: std.AutoArrayHashMap(u32, void),
 };
 
-pub fn linkWithZld(macho_file: *MachO, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn linkWithZld(macho_file: *MachO, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     const tracy = trace(@src());
     defer tracy.end();
 
src/link/Coff.zig
@@ -1442,7 +1442,7 @@ fn resolveGlobalSymbol(self: *Coff, current: SymbolWithLoc) !void {
     gop.value_ptr.* = current;
 }
 
-pub fn flush(self: *Coff, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flush(self: *Coff, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     if (self.base.options.emit == null) {
         if (build_options.have_llvm) {
             if (self.llvm_object) |llvm_object| {
@@ -1461,7 +1461,7 @@ pub fn flush(self: *Coff, comp: *Compilation, prog_node: *std.Progress.Node) !vo
     }
 }
 
-pub fn flushModule(self: *Coff, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flushModule(self: *Coff, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     const tracy = trace(@src());
     defer tracy.end();
 
src/link/Elf.zig
@@ -932,7 +932,7 @@ pub fn populateMissingMetadata(self: *Elf) !void {
     }
 }
 
-pub fn flush(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flush(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     if (self.base.options.emit == null) {
         if (build_options.have_llvm) {
             if (self.llvm_object) |llvm_object| {
@@ -951,7 +951,7 @@ pub fn flush(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) !voi
     }
 }
 
-pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     const tracy = trace(@src());
     defer tracy.end();
 
src/link/MachO.zig
@@ -405,7 +405,7 @@ pub fn createEmpty(gpa: Allocator, options: link.Options) !*MachO {
     return self;
 }
 
-pub fn flush(self: *MachO, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flush(self: *MachO, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     if (self.base.options.emit == null) {
         if (build_options.have_llvm) {
             if (self.llvm_object) |llvm_object| {
@@ -430,7 +430,7 @@ pub fn flush(self: *MachO, comp: *Compilation, prog_node: *std.Progress.Node) !v
     }
 }
 
-pub fn flushModule(self: *MachO, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flushModule(self: *MachO, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     const tracy = trace(@src());
     defer tracy.end();
 
src/link/NvPtx.zig
@@ -93,11 +93,11 @@ pub fn freeDecl(self: *NvPtx, decl_index: Module.Decl.Index) void {
     return self.llvm_object.freeDecl(decl_index);
 }
 
-pub fn flush(self: *NvPtx, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flush(self: *NvPtx, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     return self.flushModule(comp, prog_node);
 }
 
-pub fn flushModule(self: *NvPtx, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flushModule(self: *NvPtx, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     if (!build_options.have_llvm) return;
     if (build_options.skip_non_native) {
         @panic("Attempted to compile for architecture that was disabled by build configuration");
src/link/Plan9.zig
@@ -356,7 +356,7 @@ fn updateFinish(self: *Plan9, decl: *Module.Decl) !void {
     }
 }
 
-pub fn flush(self: *Plan9, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flush(self: *Plan9, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     assert(!self.base.options.use_lld);
 
     switch (self.base.options.effectiveOutputMode()) {
@@ -392,7 +392,7 @@ fn declCount(self: *Plan9) usize {
     return self.data_decl_table.count() + fn_decl_count;
 }
 
-pub fn flushModule(self: *Plan9, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flushModule(self: *Plan9, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     if (build_options.skip_non_native and builtin.object_format != .plan9) {
         @panic("Attempted to compile for object format that was disabled by build configuration");
     }
src/link/SpirV.zig
@@ -176,7 +176,7 @@ pub fn freeDecl(self: *SpirV, decl_index: Module.Decl.Index) void {
     self.decl_table.swapRemoveAt(index);
 }
 
-pub fn flush(self: *SpirV, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flush(self: *SpirV, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     if (build_options.have_llvm and self.base.options.use_lld) {
         return error.LLD_LinkingIsTODO_ForSpirV; // TODO: LLD Doesn't support SpirV at all.
     } else {
@@ -184,7 +184,7 @@ pub fn flush(self: *SpirV, comp: *Compilation, prog_node: *std.Progress.Node) !v
     }
 }
 
-pub fn flushModule(self: *SpirV, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flushModule(self: *SpirV, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     if (build_options.skip_non_native) {
         @panic("Attempted to compile for architecture that was disabled by build configuration");
     }
src/link/Wasm.zig
@@ -501,7 +501,7 @@ fn resolveSymbolsInObject(wasm: *Wasm, object_index: u16) !void {
             if (symbol.isUndefined()) {
                 log.err("Local symbols are not allowed to reference imports", .{});
                 log.err("  symbol '{s}' defined in '{s}'", .{ sym_name, object.name });
-                return error.undefinedLocal;
+                return error.UndefinedLocal;
             }
             try wasm.resolved_symbols.putNoClobber(wasm.base.allocator, location, {});
             continue;
@@ -2091,7 +2091,7 @@ fn resetState(wasm: *Wasm) void {
     wasm.debug_pubtypes_index = null;
 }
 
-pub fn flush(wasm: *Wasm, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flush(wasm: *Wasm, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     if (wasm.base.options.emit == null) {
         if (build_options.have_llvm) {
             if (wasm.llvm_object) |llvm_object| {
@@ -2107,7 +2107,7 @@ pub fn flush(wasm: *Wasm, comp: *Compilation, prog_node: *std.Progress.Node) !vo
     }
 }
 
-pub fn flushModule(wasm: *Wasm, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+pub fn flushModule(wasm: *Wasm, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
     const tracy = trace(@src());
     defer tracy.end();
 
@@ -3195,7 +3195,7 @@ fn linkWithLLD(wasm: *Wasm, comp: *Compilation, prog_node: *std.Progress.Node) !
 
                 const term = child.spawnAndWait() catch |err| {
                     log.err("unable to spawn {s}: {s}", .{ argv.items[0], @errorName(err) });
-                    return error.UnableToSpawnwasm;
+                    return error.UnableToSpawnWasm;
                 };
                 switch (term) {
                     .Exited => |code| {
@@ -3216,7 +3216,7 @@ fn linkWithLLD(wasm: *Wasm, comp: *Compilation, prog_node: *std.Progress.Node) !
 
                 const term = child.wait() catch |err| {
                     log.err("unable to spawn {s}: {s}", .{ argv.items[0], @errorName(err) });
-                    return error.UnableToSpawnwasm;
+                    return error.UnableToSpawnWasm;
                 };
 
                 switch (term) {
src/link.zig
@@ -677,9 +677,92 @@ pub const File = struct {
         }
     }
 
+    /// TODO audit this error set. most of these should be collapsed into one error,
+    /// and ErrorFlags should be updated to convey the meaning to the user.
+    pub const FlushError = error{
+        CacheUnavailable,
+        CurrentWorkingDirectoryUnlinked,
+        DivisionByZero,
+        DllImportLibraryNotFound,
+        EmptyStubFile,
+        ExpectedFuncType,
+        FailedToEmit,
+        FailedToResolveRelocationTarget,
+        FileSystem,
+        FilesOpenedWithWrongFlags,
+        FlushFailure,
+        FrameworkNotFound,
+        FunctionSignatureMismatch,
+        GlobalTypeMismatch,
+        InvalidCharacter,
+        InvalidEntryKind,
+        InvalidFormat,
+        InvalidIndex,
+        InvalidMagicByte,
+        InvalidWasmVersion,
+        LLDCrashed,
+        LLDReportedFailure,
+        LLD_LinkingIsTODO_ForSpirV,
+        LibCInstallationMissingCRTDir,
+        LibCInstallationNotAvailable,
+        LibraryNotFound,
+        LinkingWithoutZigSourceUnimplemented,
+        MalformedArchive,
+        MalformedDwarf,
+        MalformedSection,
+        MemoryTooBig,
+        MemoryTooSmall,
+        MismatchedCpuArchitecture,
+        MissAlignment,
+        MissingEndForBody,
+        MissingEndForExpression,
+        /// TODO: this should be removed from the error set in favor of using ErrorFlags
+        MissingMainEntrypoint,
+        MissingSymbol,
+        MissingTableSymbols,
+        ModuleNameMismatch,
+        MultipleSymbolDefinitions,
+        NoObjectsToLink,
+        NotObject,
+        NotObjectFile,
+        NotSupported,
+        OutOfMemory,
+        Overflow,
+        PermissionDenied,
+        StreamTooLong,
+        SwapFile,
+        SymbolCollision,
+        SymbolMismatchingType,
+        TODOImplementPlan9Objs,
+        TODOImplementWritingLibFiles,
+        TODOImplementWritingStaticLibFiles,
+        UnableToSpawnSelf,
+        UnableToSpawnWasm,
+        UnableToWriteArchive,
+        UndefinedLocal,
+        /// TODO: merge with UndefinedSymbolReference
+        UndefinedSymbol,
+        /// TODO: merge with UndefinedSymbol
+        UndefinedSymbolReference,
+        Underflow,
+        UnexpectedRemainder,
+        UnexpectedTable,
+        UnexpectedValue,
+        UnhandledDwFormValue,
+        UnhandledSymbolType,
+        UnknownFeature,
+        Unseekable,
+        UnsupportedCpuArchitecture,
+        UnsupportedVersion,
+    } ||
+        fs.File.WriteFileError ||
+        fs.File.OpenError ||
+        std.ChildProcess.SpawnError ||
+        fs.Dir.CopyFileError;
+
     /// Commit pending changes and write headers. Takes into account final output mode
     /// and `use_lld`, not only `effectiveOutputMode`.
-    pub fn flush(base: *File, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+    pub fn flush(base: *File, comp: *Compilation, prog_node: *std.Progress.Node) FlushError!void {
         if (build_options.only_c) {
             assert(base.tag == .c);
             return @fieldParentPtr(C, "base", base).flush(comp, prog_node);
@@ -717,7 +800,7 @@ pub const File = struct {
 
     /// Commit pending changes and write headers. Works based on `effectiveOutputMode`
     /// rather than final output mode.
-    pub fn flushModule(base: *File, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+    pub fn flushModule(base: *File, comp: *Compilation, prog_node: *std.Progress.Node) FlushError!void {
         if (build_options.only_c) {
             assert(base.tag == .c);
             return @fieldParentPtr(C, "base", base).flushModule(comp, prog_node);
@@ -880,7 +963,7 @@ pub const File = struct {
         }
     }
 
-    pub fn linkAsArchive(base: *File, comp: *Compilation, prog_node: *std.Progress.Node) !void {
+    pub fn linkAsArchive(base: *File, comp: *Compilation, prog_node: *std.Progress.Node) FlushError!void {
         const tracy = trace(@src());
         defer tracy.end();