significantly increase test coverage

 * add zig build option `-Dskip-libc` to skip tests that build libc
   (e.g. if you don't want to wait for musl to build)
 * add `-Denable-wine` option which uses wine to run cross compiled
   windows tests on non-windows hosts
 * add `-Denable-qemu` option which uses qemu to run cross compiled
   foreign architecture tests
 * add `-Denable-foreign-glibc=path` option which combined with
   `-Denable-qemu` enables running cross compiled tests that link
   against glibc. See
   https://github.com/ziglang/zig/wiki/Updating-libc#glibc for how to
   produce this directory.
 * the test matrix is done manually. release test builds are only
   enabled by default for the native target. this should save us some CI
   time, while still providing decent coverage of release builds.
   - add test coverage for `x86_64-linux-musl -lc` (building musl libc)
   - add test coverage for `x86_64-linux-gnu -lc` (building glibc)
   - add test coverage for `aarch64v8_5a-linux-none`
   - add test coverage for `aarch64v8_5a-linux-musl -lc` (building musl libc)
   - add test coverage for `aarch64v8_5a-linux-gnu -lc` (building glibc)
   - add test coverage for `arm-linux-none`
   - test coverage for `arm-linux-musleabihf -lc` (building musl libc) is
     disabled due to #3286
   - test coverage for `arm-linux-gnueabihf -lc` (building glibc) is disabled
     due to #3287
   - test coverage for `x86_64-windows-gnu -lc` (building mingw-w64) is
     disabled due to #3285
 * enable qemu testing on the Linux CI job. There's not really a good
   reason to enable wine, since we have a Windows CI job as well.
 * remove the no longer needed `--build-file ../build.zig` from CI
   scripts
 * fix bug in glibc compilation where it wasn't properly reading the abi
   list txt files, resulting in "key not found" error.
 * std.build.Target gains:
   - isNetBSD
   - isLinux
   - osRequiresLibC
   - getArchPtrBitWidth
   - getExternalExecutor
 * zig build system gains support for enabling wine and enabling qemu.
   `artifact.enable_wine = true;`, `artifact.enable_qemu = true;`. This
   communicates that the system has these tools installed and the build
   system will use them to run tests.
 * zig build system gains support for overriding the dynamic linker of
   an executable artifact.
 * fix std.c.lseek prototype. makes behavior tests for
   arm-linux-musleabihf pass.
 * disable std lib tests that are failing on ARM. See #3288, #3289
 * provide `std.os.off_t`.
 * disable some of the compiler_rt symbols for arm 32 bit. Fixes
   compiler_rt tests for arm 32 bit
 * add __stack_chk_guard when linking against glibc. Fixes std lib tests
   for aarch64-linux-gnu
 * workaround for "unable to inline function" using `@inlineCall`. Fixes
   compiler_rt tests for arm 32 bit.

build.zig

@@ -70,6 +70,7 @@ pub fn build(b: *Builder) !void {
     const skip_release_fast = b.option(bool, "skip-release-fast", "Main test suite skips release-fast builds") orelse skip_release;
     const skip_release_safe = b.option(bool, "skip-release-safe", "Main test suite skips release-safe builds") orelse skip_release;
     const skip_non_native = b.option(bool, "skip-non-native", "Main test suite skips non-native builds") orelse false;
+    const skip_libc = b.option(bool, "skip-libc", "Main test suite skips tests that link libc") orelse false;
     const skip_self_hosted = b.option(bool, "skip-self-hosted", "Main test suite skips building self hosted compiler") orelse false;
     if (!skip_self_hosted) {
         // TODO re-enable this after https://github.com/ziglang/zig/issues/2377
@@ -96,6 +97,10 @@ pub fn build(b: *Builder) !void {
 
     const test_filter = b.option([]const u8, "test-filter", "Skip tests that do not match filter");
 
+    const is_wine_enabled = b.option(bool, "enable-wine", "Use Wine to run cross compiled Windows tests") orelse false;
+    const is_qemu_enabled = b.option(bool, "enable-qemu", "Use QEMU to run cross compiled foreign architecture tests") orelse false;
+    const glibc_multi_dir = b.option([]const u8, "enable-foreign-glibc", "Provide directory with glibc installations to run cross compiled tests that link glibc");
+
     const test_stage2_step = b.step("test-stage2", "Run the stage2 compiler tests");
     test_stage2_step.dependOn(&test_stage2.step);
 
@@ -122,19 +127,16 @@ pub fn build(b: *Builder) !void {
     }
     const modes = chosen_modes[0..chosen_mode_index];
 
-    const multi_and_single = [_]bool{ false, true };
-    const just_multi = [_]bool{false};
-
     // run stage1 `zig fmt` on this build.zig file just to make sure it works
     test_step.dependOn(&fmt_build_zig.step);
     const fmt_step = b.step("test-fmt", "Run zig fmt against build.zig to make sure it works");
     fmt_step.dependOn(&fmt_build_zig.step);
 
-    test_step.dependOn(tests.addPkgTests(b, test_filter, "test/stage1/behavior.zig", "behavior", "Run the behavior tests", modes, multi_and_single, skip_non_native));
+    test_step.dependOn(tests.addPkgTests(b, test_filter, "test/stage1/behavior.zig", "behavior", "Run the behavior tests", modes, false, skip_non_native, skip_libc, is_wine_enabled, is_qemu_enabled, glibc_multi_dir));
 
-    test_step.dependOn(tests.addPkgTests(b, test_filter, "std/std.zig", "std", "Run the standard library tests", modes, multi_and_single, skip_non_native));
+    test_step.dependOn(tests.addPkgTests(b, test_filter, "std/std.zig", "std", "Run the standard library tests", modes, false, skip_non_native, skip_libc, is_wine_enabled, is_qemu_enabled, glibc_multi_dir));
 
-    test_step.dependOn(tests.addPkgTests(b, test_filter, "std/special/compiler_rt.zig", "compiler-rt", "Run the compiler_rt tests", modes, just_multi, skip_non_native));
+    test_step.dependOn(tests.addPkgTests(b, test_filter, "std/special/compiler_rt.zig", "compiler-rt", "Run the compiler_rt tests", modes, true, skip_non_native, true, is_wine_enabled, is_qemu_enabled, glibc_multi_dir));
 
     test_step.dependOn(tests.addCompareOutputTests(b, test_filter, modes));
     test_step.dependOn(tests.addStandaloneTests(b, test_filter, modes));

ci/azure/linux_script

@@ -12,15 +12,15 @@ sudo apt-get update -q
 
 sudo apt-get remove -y llvm-*
 sudo rm -rf /usr/local/*
-sudo apt-get install -y libxml2-dev libclang-9-dev llvm-9 llvm-9-dev cmake s3cmd gcc-7 g++-7
+sudo apt-get install -y libxml2-dev libclang-9-dev llvm-9 llvm-9-dev cmake s3cmd gcc-7 g++-7 qemu
 
 export CC=gcc-7
 export CXX=g++-7
 mkdir build
 cd build
 cmake .. -DCMAKE_BUILD_TYPE=Release
 make -j2 install
-./zig build --build-file ../build.zig test
+./zig build test -Denable-qemu
 
 if [ "${BUILD_REASON}" != "PullRequest" ]; then
   ARTIFACTSDIR="$BUILDDIR/artifacts"

ci/azure/macos_script

@@ -70,7 +70,7 @@ mkdir build
 cd build
 cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=$PREFIX -DCMAKE_INSTALL_PREFIX=$(pwd)/release -DZIG_STATIC=ON
 make $JOBS install
-release/bin/zig build --build-file ../build.zig test
+release/bin/zig build test
 
 if [ "${BUILD_REASON}" != "PullRequest" ]; then
   mv ../LICENSE release/

ci/azure/windows_script.bat

@@ -20,7 +20,7 @@ cd %ZIGBUILDDIR%
 cmake.exe .. -Thost=x64 -G"Visual Studio 15 2017 Win64" "-DCMAKE_INSTALL_PREFIX=%ZIGINSTALLDIR%" "-DCMAKE_PREFIX_PATH=%ZIGPREFIXPATH%" -DCMAKE_BUILD_TYPE=Release || exit /b
 msbuild /p:Configuration=Release INSTALL.vcxproj || exit /b
 
-"%ZIGINSTALLDIR%\bin\zig.exe" build --build-file ..\build.zig test || exit /b
+"%ZIGINSTALLDIR%\bin\zig.exe" build test || exit /b
 
 set "PATH=%CD:~0,2%\msys64\usr\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem"
 SET "MSYSTEM=MINGW64"

src/glibc.cpp

@@ -99,9 +99,9 @@ Error glibc_load_metadata(ZigGLibCAbi **out_result, Buf *zig_lib_dir, bool verbo
                 if (!opt_line.is_some) break;
 
                 ver_list_base = allocate<ZigGLibCVerList>(glibc_abi->all_functions.length);
-                ZigTarget *target = allocate<ZigTarget>(1);
                 SplitIterator line_it = memSplit(opt_line.value, str(" "));
                 for (;;) {
+                    ZigTarget *target = allocate<ZigTarget>(1);
                     Optional<Slice<uint8_t>> opt_target = SplitIterator_next(&line_it);
                     if (!opt_target.is_some) break;
 

std/build.zig

@@ -1175,6 +1175,13 @@ pub const Target = union(enum) {
         };
     }
 
+    pub fn isLinux(self: Target) bool {
+        return switch (self.getOs()) {
+            .linux => true,
+            else => false,
+        };
+    }
+
     pub fn isUefi(self: Target) bool {
         return switch (self.getOs()) {
             .uefi => true,
@@ -1196,9 +1203,125 @@ pub const Target = union(enum) {
         };
     }
 
+    pub fn isNetBSD(self: Target) bool {
+        return switch (self.getOs()) {
+            .netbsd => true,
+            else => false,
+        };
+    }
+
     pub fn wantSharedLibSymLinks(self: Target) bool {
         return !self.isWindows();
     }
+
+    pub fn osRequiresLibC(self: Target) bool {
+        return self.isDarwin() or self.isFreeBSD() or self.isNetBSD();
+    }
+
+    pub fn getArchPtrBitWidth(self: Target) u32 {
+        switch (self.getArch()) {
+            .avr,
+            .msp430,
+            => return 16,
+
+            .arc,
+            .arm,
+            .armeb,
+            .hexagon,
+            .le32,
+            .mips,
+            .mipsel,
+            .powerpc,
+            .r600,
+            .riscv32,
+            .sparc,
+            .sparcel,
+            .tce,
+            .tcele,
+            .thumb,
+            .thumbeb,
+            .i386,
+            .xcore,
+            .nvptx,
+            .amdil,
+            .hsail,
+            .spir,
+            .kalimba,
+            .shave,
+            .lanai,
+            .wasm32,
+            .renderscript32,
+            .aarch64_32,
+            => return 32,
+
+            .aarch64,
+            .aarch64_be,
+            .mips64,
+            .mips64el,
+            .powerpc64,
+            .powerpc64le,
+            .riscv64,
+            .x86_64,
+            .nvptx64,
+            .le64,
+            .amdil64,
+            .hsail64,
+            .spir64,
+            .wasm64,
+            .renderscript64,
+            .amdgcn,
+            .bpfel,
+            .bpfeb,
+            .sparcv9,
+            .s390x,
+            => return 64,
+        }
+    }
+
+    pub const Executor = union(enum) {
+        native,
+        qemu: []const u8,
+        wine: []const u8,
+        unavailable,
+    };
+
+    pub fn getExternalExecutor(self: Target) Executor {
+        if (@TagType(Target)(self) == .Native) return .native;
+
+        // If the target OS matches the host OS, we can use QEMU to emulate a foreign architecture.
+        if (self.getOs() == builtin.os) {
+            return switch (self.getArch()) {
+                .aarch64 => Executor{ .qemu = "qemu-aarch64" },
+                .aarch64_be => Executor{ .qemu = "qemu-aarch64_be" },
+                .arm => Executor{ .qemu = "qemu-arm" },
+                .armeb => Executor{ .qemu = "qemu-armeb" },
+                .i386 => Executor{ .qemu = "qemu-i386" },
+                .mips => Executor{ .qemu = "qemu-mips" },
+                .mipsel => Executor{ .qemu = "qemu-mipsel" },
+                .mips64 => Executor{ .qemu = "qemu-mips64" },
+                .mips64el => Executor{ .qemu = "qemu-mips64el" },
+                .powerpc => Executor{ .qemu = "qemu-ppc" },
+                .powerpc64 => Executor{ .qemu = "qemu-ppc64" },
+                .powerpc64le => Executor{ .qemu = "qemu-ppc64le" },
+                .riscv32 => Executor{ .qemu = "qemu-riscv32" },
+                .riscv64 => Executor{ .qemu = "qemu-riscv64" },
+                .s390x => Executor{ .qemu = "qemu-s390x" },
+                .sparc => Executor{ .qemu = "qemu-sparc" },
+                .x86_64 => Executor{ .qemu = "qemu-x86_64" },
+                else => return .unavailable,
+            };
+        }
+
+        if (self.isWindows()) {
+            switch (self.getArchPtrBitWidth()) {
+                32 => return Executor{ .wine = "wine" },
+                64 => return Executor{ .wine = "wine64" },
+                else => return .unavailable,
+            }
+        }
+
+        return .unavailable;
+    }
 };
 
 const Pkg = struct {
@@ -1266,6 +1389,7 @@ pub const LibExeObjStep = struct {
     include_dirs: ArrayList(IncludeDir),
     output_dir: ?[]const u8,
     need_system_paths: bool,
+    is_linking_libc: bool = false,
 
     installed_path: ?[]const u8,
     install_step: ?*InstallArtifactStep,
@@ -1275,6 +1399,20 @@ pub const LibExeObjStep = struct {
 
     valgrind_support: ?bool = null,
 
+    /// Uses system Wine installation to run cross compiled Windows build artifacts.
+    enable_wine: bool = false,
+
+    /// Uses system QEMU installation to run cross compiled foreign architecture build artifacts.
+    enable_qemu: bool = false,
+
+    /// After following the steps in https://github.com/ziglang/zig/wiki/Updating-libc#glibc,
+    /// this will be the directory $glibc-build-dir/install/glibcs
+    /// Given the example of the aarch64 target, this is the directory
+    /// that contains the path `aarch64-linux-gnu/lib/ld-linux-aarch64.so.1`.
+    glibc_multi_install_dir: ?[]const u8 = null,
+
+    dynamic_linker: ?[]const u8 = null,
+
     const LinkObject = union(enum) {
         StaticPath: []const u8,
         OtherStep: *LibExeObjStep,
@@ -1504,7 +1642,9 @@ pub const LibExeObjStep = struct {
 
     pub fn linkSystemLibrary(self: *LibExeObjStep, name: []const u8) void {
         self.link_objects.append(LinkObject{ .SystemLib = self.builder.dupe(name) }) catch unreachable;
-        if (!isLibCLibrary(name)) {
+        if (isLibCLibrary(name)) {
+            self.is_linking_libc = true;
+        } else {
             self.need_system_paths = true;
         }
     }
@@ -1840,6 +1980,11 @@ pub const LibExeObjStep = struct {
             zig_args.append(builder.pathFromRoot(linker_script)) catch unreachable;
         }
 
+        if (self.dynamic_linker) |dynamic_linker| {
+            try zig_args.append("--dynamic-linker");
+            try zig_args.append(dynamic_linker);
+        }
+
         if (self.version_script) |version_script| {
             try zig_args.append("--version-script");
             try zig_args.append(builder.pathFromRoot(version_script));
@@ -1854,6 +1999,34 @@ pub const LibExeObjStep = struct {
                     try zig_args.append("--test-cmd-bin");
                 }
             }
+        } else switch (self.target.getExternalExecutor()) {
+            .native, .unavailable => {},
+            .qemu => |bin_name| if (self.enable_qemu) qemu: {
+                const need_cross_glibc = self.target.isGnu() and self.target.isLinux() and self.is_linking_libc;
+                const glibc_dir_arg = if (need_cross_glibc)
+                    self.glibc_multi_install_dir orelse break :qemu
+                else
+                    null;
+                try zig_args.append("--test-cmd");
+                try zig_args.append(bin_name);
+                if (glibc_dir_arg) |dir| {
+                    const full_dir = try fs.path.join(builder.allocator, [_][]const u8{
+                        dir,
+                        try self.target.linuxTriple(builder.allocator),
+                    });
+
+                    try zig_args.append("--test-cmd");
+                    try zig_args.append("-L");
+                    try zig_args.append("--test-cmd");
+                    try zig_args.append(full_dir);
+                }
+                try zig_args.append("--test-cmd-bin");
+            },
+            .wine => |bin_name| if (self.enable_wine) {
+                try zig_args.append("--test-cmd");
+                try zig_args.append(bin_name);
+                try zig_args.append("--test-cmd-bin");
+            },
         }
         for (self.packages.toSliceConst()) |pkg| {
             zig_args.append("--pkg-begin") catch unreachable;

std/c.zig

@@ -63,7 +63,7 @@ pub extern "c" fn close(fd: fd_t) c_int;
 pub extern "c" fn @"close$NOCANCEL"(fd: fd_t) c_int;
 pub extern "c" fn fstat(fd: fd_t, buf: *Stat) c_int;
 pub extern "c" fn @"fstat$INODE64"(fd: fd_t, buf: *Stat) c_int;
-pub extern "c" fn lseek(fd: fd_t, offset: isize, whence: c_int) isize;
+pub extern "c" fn lseek(fd: fd_t, offset: off_t, whence: c_int) off_t;
 pub extern "c" fn open(path: [*]const u8, oflag: c_uint, ...) c_int;
 pub extern "c" fn openat(fd: c_int, path: [*]const u8, oflag: c_uint, ...) c_int;
 pub extern "c" fn raise(sig: c_int) c_int;

std/fmt/parse_float.zig

@@ -382,6 +382,10 @@ pub fn parseFloat(comptime T: type, s: []const u8) !T {
 }
 
 test "fmt.parseFloat" {
+    if (@import("builtin").arch == .arm) {
+        // TODO https://github.com/ziglang/zig/issues/3289
+        return error.SkipZigTest;
+    }
     const testing = std.testing;
     const expect = testing.expect;
     const expectEqual = testing.expectEqual;

std/fs/path.zig

@@ -646,6 +646,10 @@ test "resolve" {
 }
 
 test "resolveWindows" {
+    if (@import("builtin").arch == .aarch64) {
+        // TODO https://github.com/ziglang/zig/issues/3288
+        return error.SkipZigTest;
+    }
     if (windows.is_the_target) {
         const cwd = try process.getCwdAlloc(debug.global_allocator);
         const parsed_cwd = windowsParsePath(cwd);
@@ -1086,6 +1090,10 @@ pub fn relativePosix(allocator: *Allocator, from: []const u8, to: []const u8) ![
 }
 
 test "relative" {
+    if (@import("builtin").arch == .aarch64) {
+        // TODO https://github.com/ziglang/zig/issues/3288
+        return error.SkipZigTest;
+    }
     testRelativeWindows("c:/blah\\blah", "d:/games", "D:\\games");
     testRelativeWindows("c:/aaaa/bbbb", "c:/aaaa", "..");
     testRelativeWindows("c:/aaaa/bbbb", "c:/cccc", "..\\..\\cccc");

std/io/test.zig

@@ -11,6 +11,10 @@ const fs = std.fs;
 const File = std.fs.File;
 
 test "write a file, read it, then delete it" {
+    if (builtin.arch == .aarch64 and builtin.glibc_version != null) {
+        // TODO https://github.com/ziglang/zig/issues/3288
+        return error.SkipZigTest;
+    }
     var raw_bytes: [200 * 1024]u8 = undefined;
     var allocator = &std.heap.FixedBufferAllocator.init(raw_bytes[0..]).allocator;
 

std/os/bits/darwin.zig

@@ -43,6 +43,8 @@ pub const mach_timebase_info_data = extern struct {
     denom: u32,
 };
 
+pub const off_t = i64;
+
 /// Renamed to Stat to not conflict with the stat function.
 /// atime, mtime, and ctime have functions to return `timespec`,
 /// because although this is a POSIX API, the layout and names of
@@ -65,7 +67,7 @@ pub const Stat = extern struct {
     ctimensec: isize,
     birthtimesec: isize,
     birthtimensec: isize,
-    size: i64,
+    size: off_t,
     blocks: i64,
     blksize: i32,
     flags: u32,