openkal-musl: name this system's own linker, for the fifteen indirect symbols

Author: Sunrisepeak

mcpp.toml

@@ -168,7 +168,23 @@ ldflags = ["-nostdlib", "-static", "-Wl,--no-dynamic-linker",
 # is loaded. This format has no such headers, and the operation it names is one
 # openkal does not offer in any case.
 sources = ["!musl/src/ldso/dl_iterate_phdr.c"]
-ldflags = ["-nostdlib", "-lSystem", "-Wl,-e,_okm_start", "-Wl,-dead_strip"]
+#
+# --ld-path names this system's own linker rather than the one the toolchain
+# brings. The reason is one construct and fifteen uses of it. A second name for
+# a definition is made here with the assembler's own directive; where the
+# definition is in the same translation unit that produces an ordinary symbol,
+# and where it is not --- fifteen names in musl, every one of them a function
+# declared in a header and defined elsewhere --- it produces an indirect symbol,
+# which is what that directive is for. The toolchain's linker refuses an
+# indirect symbol, in as many words: "TODO: support aliasing to symbols of kind
+# 1". This system's own linker is the one the format was designed alongside and
+# resolves them.
+#
+# The measurement: 1154 of musl's translation units compiled for this system
+# produce fifteen indirect symbols between them, and they are listed in
+# musl/PATCHES.md.
+ldflags = ["-nostdlib", "-lSystem", "--ld-path=/usr/bin/ld",
+           "-Wl,-e,_okm_start", "-Wl,-dead_strip"]
 
 # The generated headers, per architecture and per data model.
 #

musl/PATCHES.md

@@ -138,3 +138,25 @@ not know that a program is a kind of file.
 `fork` is absent and stays absent. Duplicating a running image is not something
 every environment can produce. `posix_spawn`, and therefore `system` and
 `popen`, are supplied, because musl builds them on starting a program.
+
+### The fifteen indirect symbols
+
+Where the definition a second name is made for is in the same translation unit,
+the assembler's directive produces an ordinary symbol at that address. Where it
+is not, it produces an *indirect* symbol, which is the other thing that
+directive is for and which one linker refuses in as many words: `TODO: support
+aliasing to symbols of kind 1`.
+
+The measurement: 1154 of musl's translation units compiled for that system
+produce fifteen such symbols between them, and every one is a function declared
+in a header and defined in another unit.
+
+```
+dladdr, dlopen, __dlsym, __dl_invalid_handle, __libc_exit_fini, malloc,
+pthread_detach, pthread_equal, pthread_getspecific, pthread_tryjoin_np,
+thrd_detach, thrd_equal, tss_get, utmpname, utmpxname
+```
+
+The response is one flag on the link line rather than fifteen exceptions in a
+macro: the link names that system's own linker, which is the one its object
+format was designed alongside and which resolves an indirect symbol.