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std.build: Fix transitive linkSystemLibraryName() dependencies

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Currently transitive system library dependencies are always linked using
linkSystemLibrary() and therefore pkg-config even if they were
originally specified with linkSystemLibraryName() instead. This causes
problems in practice for projects needing total control over exactly
what library is linked, such as the mach game engine.

This is fixed by keeping track of whether libraries are to be linked
with pkg-config or not and holding off on actually running pkg-config
until after transitive dependency resolution in LibExeObjStep.make().

This also fixes a separate issue with the pkg-config handling that could
cause partial application of pkg-config flags if the first part of the
pkg-config output parses correctly but there is an error later on. This
error isn't always fatal as we fall back to a plain -lfoo in the case of
linkSystemLibrary().
This commit is contained in:
Isaac Freund
2022-04-12 00:25:47 +02:00
committed by Andrew Kelley
parent b9d86c6bc8
commit 38d6e1d8a8
1 changed files with 120 additions and 50 deletions
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170
lib/std/build.zig
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@@ -1600,12 +1600,26 @@ pub const LibExeObjStep = struct {
pub const LinkObject = union(enum) {
static_path: FileSource,
other_step: *LibExeObjStep,
system_lib: []const u8,
system_lib: SystemLib,
assembly_file: FileSource,
c_source_file: *CSourceFile,
c_source_files: *CSourceFiles,
};
pub const SystemLib = struct {
name: []const u8,
use_pkg_config: enum {
/// Don't use pkg-config, just pass -lfoo where foo is name.
no,
/// Try to get information on how to link the library from pkg-config.
/// If that fails, fall back to passing -lfoo where foo is name.
yes,
/// Try to get information on how to link the library from pkg-config.
/// If that fails, error out.
force,
},
};
pub const IncludeDir = union(enum) {
raw_path: []const u8,
raw_path_system: []const u8,
@@ -1854,7 +1868,7 @@ pub const LibExeObjStep = struct {
}
for (self.link_objects.items) |link_object| {
switch (link_object) {
.system_lib => |n| if (mem.eql(u8, n, name)) return true,
.system_lib => |lib| if (mem.eql(u8, lib.name, name)) return true,
else => continue,
}
}
@@ -1879,14 +1893,24 @@ pub const LibExeObjStep = struct {
pub fn linkLibC(self: *LibExeObjStep) void {
if (!self.is_linking_libc) {
self.is_linking_libc = true;
self.link_objects.append(.{ .system_lib = "c" }) catch unreachable;
self.link_objects.append(.{
.system_lib = .{
.name = "c",
.use_pkg_config = .no,
},
}) catch unreachable;
}
}
pub fn linkLibCpp(self: *LibExeObjStep) void {
if (!self.is_linking_libcpp) {
self.is_linking_libcpp = true;
self.link_objects.append(.{ .system_lib = "c++" }) catch unreachable;
self.link_objects.append(.{
.system_lib = .{
.name = "c++",
.use_pkg_config = .no,
},
}) catch unreachable;
}
}
@@ -1905,12 +1929,28 @@ pub const LibExeObjStep = struct {
/// This one has no integration with anything, it just puts -lname on the command line.
/// Prefer to use `linkSystemLibrary` instead.
pub fn linkSystemLibraryName(self: *LibExeObjStep, name: []const u8) void {
self.link_objects.append(.{ .system_lib = self.builder.dupe(name) }) catch unreachable;
self.link_objects.append(.{
.system_lib = .{
.name = self.builder.dupe(name),
.use_pkg_config = .no,
},
}) catch unreachable;
}
/// This links against a system library, exclusively using pkg-config to find the library.
/// Prefer to use `linkSystemLibrary` instead.
pub fn linkSystemLibraryPkgConfigOnly(self: *LibExeObjStep, lib_name: []const u8) !void {
pub fn linkSystemLibraryPkgConfigOnly(self: *LibExeObjStep, lib_name: []const u8) void {
self.link_objects.append(.{
.system_lib = .{
.name = self.builder.dupe(lib_name),
.use_pkg_config = .force,
},
}) catch unreachable;
}
/// Run pkg-config for the given library name and parse the output, returning the arguments
/// that should be passed to zig to link the given library.
fn runPkgConfig(self: *LibExeObjStep, lib_name: []const u8) ![]const []const u8 {
const pkg_name = match: {
// First we have to map the library name to pkg config name. Unfortunately,
// there are several examples where this is not straightforward:
@@ -1970,34 +2010,38 @@ pub const LibExeObjStep = struct {
error.ChildExecFailed => return error.PkgConfigFailed,
else => return err,
};
var zig_args = std.ArrayList([]const u8).init(self.builder.allocator);
defer zig_args.deinit();
var it = mem.tokenize(u8, stdout, " \r\n\t");
while (it.next()) |tok| {
if (mem.eql(u8, tok, "-I")) {
const dir = it.next() orelse return error.PkgConfigInvalidOutput;
self.addIncludePath(dir);
try zig_args.appendSlice(&[_][]const u8{ "-I", dir });
} else if (mem.startsWith(u8, tok, "-I")) {
self.addIncludePath(tok["-I".len..]);
try zig_args.append(tok);
} else if (mem.eql(u8, tok, "-L")) {
const dir = it.next() orelse return error.PkgConfigInvalidOutput;
self.addLibraryPath(dir);
try zig_args.appendSlice(&[_][]const u8{ "-L", dir });
} else if (mem.startsWith(u8, tok, "-L")) {
self.addLibraryPath(tok["-L".len..]);
try zig_args.append(tok);
} else if (mem.eql(u8, tok, "-l")) {
const lib = it.next() orelse return error.PkgConfigInvalidOutput;
self.linkSystemLibraryName(lib);
try zig_args.appendSlice(&[_][]const u8{ "-l", lib });
} else if (mem.startsWith(u8, tok, "-l")) {
self.linkSystemLibraryName(tok["-l".len..]);
try zig_args.append(tok);
} else if (mem.eql(u8, tok, "-D")) {
const macro = it.next() orelse return error.PkgConfigInvalidOutput;
self.defineCMacroRaw(macro);
try zig_args.appendSlice(&[_][]const u8{ "-D", macro });
} else if (mem.startsWith(u8, tok, "-D")) {
self.defineCMacroRaw(tok["-D".len..]);
} else if (mem.eql(u8, tok, "-pthread")) {
self.linkLibC();
try zig_args.append(tok);
} else if (self.builder.verbose) {
warn("Ignoring pkg-config flag '{s}'\n", .{tok});
}
}
return zig_args.toOwnedSlice();
}
pub fn linkSystemLibrary(self: *LibExeObjStep, name: []const u8) void {
@@ -2009,21 +2053,13 @@ pub const LibExeObjStep = struct {
self.linkLibCpp();
return;
}
if (self.linkSystemLibraryPkgConfigOnly(name)) |_| {
// pkg-config worked, so nothing further needed to do.
return;
} else |err| switch (err) {
error.PkgConfigInvalidOutput,
error.PkgConfigCrashed,
error.PkgConfigFailed,
error.PkgConfigNotInstalled,
error.PackageNotFound,
=> {},
else => unreachable,
}
self.linkSystemLibraryName(name);
self.link_objects.append(.{
.system_lib = .{
.name = self.builder.dupe(name),
.use_pkg_config = .yes,
},
}) catch unreachable;
}
pub fn setNamePrefix(self: *LibExeObjStep, text: []const u8) void {
@@ -2317,27 +2353,34 @@ pub const LibExeObjStep = struct {
var prev_has_extra_flags = false;
// Resolve transitive dependencies
for (self.link_objects.items) |link_object| {
switch (link_object) {
.other_step => |other| {
// Inherit dependency on system libraries
for (other.link_objects.items) |other_link_object| {
switch (other_link_object) {
.system_lib => |name| self.linkSystemLibrary(name),
else => continue,
}
}
{
var transitive_dependencies = std.ArrayList(LinkObject).init(builder.allocator);
defer transitive_dependencies.deinit();
// Inherit dependencies on darwin frameworks
if (!other.isDynamicLibrary()) {
var it = other.frameworks.iterator();
while (it.next()) |framework| {
self.frameworks.insert(framework.*) catch unreachable;
for (self.link_objects.items) |link_object| {
switch (link_object) {
.other_step => |other| {
// Inherit dependency on system libraries
for (other.link_objects.items) |other_link_object| {
switch (other_link_object) {
.system_lib => try transitive_dependencies.append(other_link_object),
else => continue,
}
}
}
},
else => continue,
// Inherit dependencies on darwin frameworks
if (!other.isDynamicLibrary()) {
var it = other.frameworks.iterator();
while (it.next()) |framework| {
self.frameworks.insert(framework.*) catch unreachable;
}
}
},
else => continue,
}
}
try self.link_objects.appendSlice(transitive_dependencies.items);
}
for (self.link_objects.items) |link_object| {
@@ -2363,8 +2406,35 @@ pub const LibExeObjStep = struct {
}
},
},
.system_lib => |name| {
try zig_args.append(builder.fmt("-l{s}", .{name}));
.system_lib => |system_lib| {
switch (system_lib.use_pkg_config) {
.no => try zig_args.append(builder.fmt("-l{s}", .{system_lib.name})),
.yes, .force => {
if (self.runPkgConfig(system_lib.name)) |args| {
try zig_args.appendSlice(args);
} else |err| switch (err) {
error.PkgConfigInvalidOutput,
error.PkgConfigCrashed,
error.PkgConfigFailed,
error.PkgConfigNotInstalled,
error.PackageNotFound,
=> switch (system_lib.use_pkg_config) {
.yes => {
// pkg-config failed, so fall back to linking the library
// by name directly.
try zig_args.append(builder.fmt("-l{s}", .{system_lib.name}));
},
.force => {
panic("pkg-config failed for library {s}", .{system_lib.name});
},
.no => unreachable,
},
else => |e| return e,
}
},
}
},
.assembly_file => |asm_file| {