The C cases link without DWARF: the testcases ROOT goes from 305 to 209 MiB, and the checkout-path issue records the paths every guest binary carries

issues/two-checkouts-of-one-tree-build-different-guest-bytes.md

@@ -14,14 +14,35 @@ into two target directories gave identical ones. The LLVM is held
 fixed here: two builds of one LLVM key differing is
 `issues/two-builds-of-one-llvm-key-differ-in-their-bytes.md`.
 
-- The kernel carries no path and differs, on both architectures, in nothing
-  `strings` shows but local symbols' `.llvm.<n>` suffixes, which LLVM derives
-  from the module's identity: 2362 symbols on x86_64 and 2093 on AArch64.
-- `snake` carries no path, and still differs the same way: 203 symbols.
+- The kernel carries no path into a checkout and differs, on both
+  architectures, in nothing `strings` shows but local symbols' `.llvm.<n>`
+  suffixes, which LLVM derives from the module's identity: 2362 symbols on
+  x86_64 and 2093 on AArch64.
+- `snake` carries no path into the checkout that built it, and still differs
+  the same way: 203 symbols.
 - The bootloader is byte-identical at two paths, on both architectures. It
   and the kernel carried each path dependency's absolute source path in their
   panic locations while each was its own workspace root; in one workspace
   cargo hands rustc every path package's source relative to the root.
+- A workspace of its own still does that. 45 of the 100 `test_rs_*` binaries
+  and `libtls_cranelift.so` on the `testcases` ROOT carry the building
+  checkout's absolute path: `toyos`'s and `toyos-abi`'s panic locations, and
+  cranelift-codegen's generated sources under the cdylib's own target
+  directory.
+- Every guest binary carries the path of the checkout that built the sysroot
+  store's std and C library, not the one building: chiefly the panic
+  locations of their path dependencies `toyos`, `toyos-abi` and
+  `toyos-osrelease`. A worktree whose sysroot came from the store carries
+  another checkout's path. On the `testcases` ROOT that is all 250 ELF
+  files (23 in each C case, 6 in `fileserver`), and on the `cargo run` ROOT
+  all 27 programs (6 in `snake`).
+- Every guest binary, the kernel and the bootloader carry the cargo home's
+  absolute path: the panic locations of registry and git dependencies (36 in
+  `snake`, 7 in the kernel, 40 in the bootloader). Two checkouts on one host
+  share it; two hosts do not.
+
+`LC_ALL=C grep -a -o "$HOME/" <binary> | wc -l` counts a binary's paths under
+the home directory; `snake` gives 42, its 6 and 36.
 
 Nothing remaps either: no `--remap-path-prefix`, no `trim-paths`. Until both
 are path-independent a Linux build and a macOS build cannot be compared either,

tests/common/compile.rs

@@ -110,11 +110,17 @@ const LINK_FLAGS: &[(&str, &[&str])] = &[
 /// Link `objects` into a ToyOS executable through the clang driver — which
 /// names `ld.lld` and the sysroot's `libtoyos_c.a`, and makes a PIE — and
 /// return its bytes.
+///
+/// **Without DWARF, and with `.symtab`**, as `[profile.toyos]` links every Rust
+/// guest binary: the archive brings its Rust libraries' DWARF into every case
+/// and nothing reads it, while `symbolize` and the loader's dlopen binding read
+/// `.symtab`.
 pub fn link_toyos(objects: &[PathBuf], name: &str) -> Vec<u8> {
     let c = c_sysroot();
     let out = scratch(name, ".elf");
     let output = Command::new(&c.clang)
         .args(c.args())
+        .arg("-Wl,--strip-debug")
         .args(objects)
         .args(LINK_FLAGS.iter().filter(|(case, _)| *case == name).flat_map(|(_, flags)| flags.iter()))
         .arg("-o")