zig ld: handle `--library :path/to/lib.so`

`-l :path/to/lib.so` behavior on gcc/clang is:

- the path is recorded as-is: no paths, exact filename (`libX.so.Y`).
- no rpaths.

The previous version removed the `:` and pretended it's a positional
argument to the linker. That works in almost all cases, except in how
rules_go[1] does things (the Bazel wrapper for Go).

Test case in #15743, output:

    gcc rpath:
     0x0000000000000001 (NEEDED)     Shared library: [libversioned.so.2]
     0x000000000000001d (RUNPATH)    Library runpath: [$ORIGIN/x]
    gcc plain:
     0x0000000000000001 (NEEDED)     Shared library: [libversioned.so.2]
    zig cc rpath:
     0x0000000000000001 (NEEDED)     Shared library: [libversioned.so.2]
     0x000000000000001d (RUNPATH)    Library runpath: [$ORIGIN/x]
    zig cc plain:
     0x0000000000000001 (NEEDED)     Shared library: [libversioned.so.2]

Fixes #15743

[1]: https://github.com/bazelbuild/rules_go

1 files changed, 8 insertions, 2 deletions

diff --git a/src/Compilation.zig b/src/Compilation.zig
index cc2e2a916b..2ab9dde35c 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -451,6 +451,11 @@ pub const CacheMode = link.CacheMode;
 pub const LinkObject = struct {
     path: []const u8,
     must_link: bool = false,
+    // When the library is passed via a positional argument, it will be
+    // added as a full path. If it's `-l<lib>`, then just the basename.
+    //
+    // Consistent with `withLOption` variable name in lld ELF driver.
+    loption: bool = false,
 };
 
 pub const InitOptions = struct {
@@ -2196,7 +2201,7 @@ fn prepareWholeEmitSubPath(arena: Allocator, opt_emit: ?EmitLoc) error{OutOfMemo
 /// to remind the programmer to update multiple related pieces of code that
 /// are in different locations. Bump this number when adding or deleting
 /// anything from the link cache manifest.
-pub const link_hash_implementation_version = 8;
+pub const link_hash_implementation_version = 9;
 
 fn addNonIncrementalStuffToCacheManifest(comp: *Compilation, man: *Cache.Manifest) !void {
     const gpa = comp.gpa;
@@ -2206,7 +2211,7 @@ fn addNonIncrementalStuffToCacheManifest(comp: *Compilation, man: *Cache.Manifes
     defer arena_allocator.deinit();
     const arena = arena_allocator.allocator();
 
-    comptime assert(link_hash_implementation_version == 8);
+    comptime assert(link_hash_implementation_version == 9);
 
     if (comp.bin_file.options.module) |mod| {
         const main_zig_file = try mod.main_pkg.root_src_directory.join(arena, &[_][]const u8{
@@ -2244,6 +2249,7 @@ fn addNonIncrementalStuffToCacheManifest(comp: *Compilation, man: *Cache.Manifes
     for (comp.bin_file.options.objects) |obj| {
         _ = try man.addFile(obj.path, null);
         man.hash.add(obj.must_link);
+        man.hash.add(obj.loption);
     }
 
     for (comp.c_object_table.keys()) |key| {