test(trim-paths): verify SO symbols didn't get remapped

When `--remap-path-scope=object` is specified, user expect that there is
no local path embedded in final executables. Under `object` scope, the
current implementation only remap debug symbols if debug info is
splitted into its own file. In other words, when
`split-debuginfo=packed|unpacked` is set, rustc assumes there is no
embedded path in the final executable needing to be remapped.

However, this doesn't work on macOS. On macOS, `SO` symbols are embedded
in binary executables and libraries regardless a split-debuginfo file is
built. Each `SO` symbol contains a path to the root source file of a
debug info compile unit.

This commit demonstrates the case, and hope there is a fix soon.

tests/run-make/split-debuginfo/Makefile

@@ -1,6 +1,8 @@
 # ignore-cross-compile
 include ../tools.mk
 
+export HERE := $(shell pwd)
+
 all: off packed unpacked
 
 ifeq ($(UNAME),Darwin)
@@ -11,23 +13,69 @@ off:
 	[ ! -d $(TMPDIR)/foo.dSYM ]
 
 # Packed by default, but only if debuginfo is requested
-packed:
-	rm -rf $(TMPDIR)/*.dSYM
-	$(RUSTC) foo.rs
-	[ ! -d $(TMPDIR)/foo.dSYM ]
-	rm -rf $(TMPDIR)/*.dSYM
-	$(RUSTC) foo.rs -g
+packed: packed-remapped-scope packed-remapped-wrong-scope
+
+# - Debuginfo in binary file
+# - file paths from `SO` (source files) and `OSO` (object files) should be remapped
+packed-remapped-scope:
+	$(RUSTC) $(UNSTABLEOPTS) -C split-debuginfo=packed -C debuginfo=2 \
+		--remap-path-prefix $(TMPDIR)=/a \
+		--remap-path-prefix $(HERE)=/b \
+		-Z remap-path-scope=object foo.rs -g
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
 	[ -d $(TMPDIR)/foo.dSYM ]
-	rm -rf $(TMPDIR)/*.dSYM
-	$(RUSTC) foo.rs -g -C split-debuginfo=packed
+	dsymutil -s $(TMPDIR)/foo | grep 'N_SO' | grep $(HERE) || exit 1 # expected behavior is (! grep ...)
+	# As of 2023-12, `OSO` should be the only thing that cannot be trimmed. See rust-lang/rust#116948
+	dsymutil -s $(TMPDIR)/foo | grep 'N_OSO' | grep $(TMPDIR) || exit 1 # expected behavior is (! grep ...)
+	rm -rf $(TMPDIR)/foo.dSYM
+	rm $(TMPDIR)/$(call BIN,foo)
+
+# - Debuginfo in binary file
+# - file paths from `N_SO` (source files) and `N_OSO` (object files) shouldn't be remapped
+packed-remapped-wrong-scope:
+	$(RUSTC) $(UNSTABLEOPTS) -C split-debuginfo=packed -C debuginfo=2 \
+		--remap-path-prefix $(TMPDIR)=/a \
+		--remap-path-prefix $(HERE)=/b \
+		-Z remap-path-scope=macro foo.rs -g
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
 	[ -d $(TMPDIR)/foo.dSYM ]
-	rm -rf $(TMPDIR)/*.dSYM
+	dsymutil -s $(TMPDIR)/foo | grep 'N_SO' | grep $(HERE) || exit 1
+	dsymutil -s $(TMPDIR)/foo | grep 'N_OSO' | grep $(TMPDIR) || exit 1
+	rm -rf $(TMPDIR)/foo.dSYM
+	rm $(TMPDIR)/$(call BIN,foo)
 
 # Object files are preserved with unpacked and `dsymutil` isn't run
-unpacked:
-	$(RUSTC) foo.rs -g -C split-debuginfo=unpacked
+unpacked: unpacked-remapped-scope #unpacked-remapped-wrong-scope
+
+# - Debuginfo in object files
+# - file paths from `N_SO` (source files) and `N_OSO` (object files) should be remapped
+unpacked-remapped-scope:
+	$(RUSTC) $(UNSTABLEOPTS) -C split-debuginfo=unpacked -C debuginfo=2 \
+		--remap-path-prefix $(TMPDIR)=/a \
+		--remap-path-prefix $(HERE)=/b \
+		-Z remap-path-scope=object foo.rs -g
 	ls $(TMPDIR)/*.o
 	[ ! -d $(TMPDIR)/foo.dSYM ]
+	dsymutil -s $(TMPDIR)/foo | grep 'N_SO' | (grep $(HERE)) || exit 1 # expected behavior is (! grep ...)
+	# As of 2023-12, `OSO` should be the only thing that cannot be trimmed. See rust-lang/rust#116948
+	dsymutil -s $(TMPDIR)/foo | grep 'N_OSO' | (grep $(TMPDIR)) || exit 1 # expected behavior is (! grep ...)
+	rm $(TMPDIR)/*.o
+	rm $(TMPDIR)/$(call BIN,foo)
+
+# - Debuginfo in object files
+# - file paths from `N_SO` (source files) and `N_OSO` (object files) shouldn't be remapped
+unpacked-remapped-wrong-scope:
+	$(RUSTC) $(UNSTABLEOPTS) -C split-debuginfo=unpacked -C debuginfo=2 \
+		--remap-path-prefix $(TMPDIR)=/a \
+		--remap-path-prefix $(HERE)=/b \
+		-Z remap-path-scope=macro foo.rs -g
+	ls $(TMPDIR)/*.o
+	[ ! -d $(TMPDIR)/foo.dSYM ]
+	dsymutil -s $(TMPDIR)/foo | grep 'N_SO' | (grep $(HERE)) || exit 1
+	dsymutil -s $(TMPDIR)/foo | grep 'N_OSO' | (grep $(TMPDIR)) || exit 1
+	rm $(TMPDIR)/*.o
+	rm $(TMPDIR)/$(call BIN,foo)
+
 else
 ifdef IS_WINDOWS
 # Windows only supports packed debuginfo - nothing to test.