From 313d1cc6931724ea931a72a132a200609b306478 Mon Sep 17 00:00:00 2001
From: Pat Tullmann <pat.github@tullmann.org>
Date: Sun, 29 Oct 2023 17:59:23 -0700
Subject: [PATCH] src/glibc: Do some arch-specific glibc version checks

Some architectures are only supported, by glibc, at more recent versions.
So add some checks for these systems.

Issue #17769
---
 src/glibc.zig  | 42 ++++++++++++++++++++++++++++++++++++++++++
 src/target.zig |  6 +++---
 2 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/src/glibc.zig b/src/glibc.zig
index 0562d41c86eb..5bc1492f7390 100644
--- a/src/glibc.zig
+++ b/src/glibc.zig
@@ -746,6 +746,8 @@ pub fn buildSharedObjects(comp: *Compilation, prog_node: *std.Progress.Node) !vo
         return error.InvalidTargetGLibCVersion;
     }
 
+    try isArchSupportedGlibcVersion(target, target_version);
+
     {
         var map_contents = std.ArrayList(u8).init(arena);
         for (metadata.all_versions[0 .. target_ver_index + 1]) |ver| {
@@ -1142,3 +1144,43 @@ pub fn needsCrtiCrtn(target: std.Target) bool {
 pub fn isSupportedGlibcVersion(ver: Version) bool {
     return (ver.major > 2) or ((ver.major == 2) and (ver.minor >= 17));
 }
+
+// Check if given glibc version is supported by target's architecture.  Note that
+// target.zig's `available_libcs` should filter out many architectures before this.
+pub fn isArchSupportedGlibcVersion(target: std.Target, ver: Version) !void {
+    // See https://github.com/ziglang/zig/issues/17769
+    switch (target.cpu.arch) {
+        .powerpc64le => {
+            if ((ver.major < 2) or ((ver.major == 2) and (ver.minor < 19))) {
+                log.warn("{s} only supported on glibc v2.19+", .{@tagName(target.cpu.arch)});
+                return error.InvalidTargetGLibCVersion;
+            }
+        },
+        .riscv64 => {
+            if ((ver.major < 2) or ((ver.major == 2) and (ver.minor < 27))) {
+                log.warn("{s} only supported on glibc v2.27+", .{@tagName(target.cpu.arch)});
+                return error.InvalidTargetGLibCVersion;
+            }
+        },
+
+        // For many architectures, glibc support is older than the Zig
+        // minimum (v2.17), so we don't need to check specifics.
+        .aarch64,
+        .aarch64_be,
+        .arm,
+        .m68k,
+        .powerpc64,
+        .powerpc,
+        .sparc,
+        .sparc64,
+        .x86,
+        .x86_64,
+        => return,
+
+        // Other platforms are ... unknown?
+        else => {
+            log.warn("{s} has undefined glibc support.  Please file a bug.", .{@tagName(target.cpu.arch)});
+            return error.InvalidTargetGLibCVersion;
+        },
+    }
+}
diff --git a/src/target.zig b/src/target.zig
index c137166543d1..513c885cc341 100644
--- a/src/target.zig
+++ b/src/target.zig
@@ -11,7 +11,7 @@ pub const ArchOsAbi = struct {
 };
 
 pub const available_libcs = [_]ArchOsAbi{
-    .{ .arch = .aarch64_be, .os = .linux, .abi = .gnu },
+    .{ .arch = .aarch64_be, .os = .linux, .abi = .gnu }, // glibc aarch64 v2.17+
     .{ .arch = .aarch64_be, .os = .linux, .abi = .musl },
     .{ .arch = .aarch64_be, .os = .windows, .abi = .gnu },
     .{ .arch = .aarch64, .os = .linux, .abi = .gnu },
@@ -51,14 +51,14 @@ pub const available_libcs = [_]ArchOsAbi{
     .{ .arch = .mips, .os = .linux, .abi = .gnueabi },
     .{ .arch = .mips, .os = .linux, .abi = .gnueabihf },
     .{ .arch = .mips, .os = .linux, .abi = .musl },
-    .{ .arch = .powerpc64le, .os = .linux, .abi = .gnu },
+    .{ .arch = .powerpc64le, .os = .linux, .abi = .gnu }, // glibc powerpc64le v2.19+
     .{ .arch = .powerpc64le, .os = .linux, .abi = .musl },
     .{ .arch = .powerpc64, .os = .linux, .abi = .gnu },
     .{ .arch = .powerpc64, .os = .linux, .abi = .musl },
     .{ .arch = .powerpc, .os = .linux, .abi = .gnueabi },
     .{ .arch = .powerpc, .os = .linux, .abi = .gnueabihf },
     .{ .arch = .powerpc, .os = .linux, .abi = .musl },
-    .{ .arch = .riscv64, .os = .linux, .abi = .gnu },
+    .{ .arch = .riscv64, .os = .linux, .abi = .gnu }, // glibc riscv v2.27+
     .{ .arch = .riscv64, .os = .linux, .abi = .musl },
     .{ .arch = .s390x, .os = .linux, .abi = .gnu },
     .{ .arch = .s390x, .os = .linux, .abi = .musl },