Without them they can be merged with non unnamed_addr constants during LTO.
The resulting constant is not unnamed_addr and goes in a different section,
which causes ld64 to crash.
A testcase that would crash before:
* file1.mm:
void g(id notification) {
[notification valueForKey:@"name"];
}
* file2.cpp:
extern const char js_name_str[] = "name";
* file3.cpp
extern bool JS_GetProperty(const char *name);
extern const char js_name_str[];
bool js_ReportUncaughtException() { JS_GetProperty(js_name_str); }
run
clang file1.mm -o file1.o -c -w -emit-llvm
clang file2.cpp -o file2.o -c -w -emit-llvm
clang file3.cpp -o file3.o -c -w
ld -dylib -o XUL file1.o file2.o file3.o -undefined dynamic_lookup.
llvm-svn: 199688
section. A 'normal' string will go into the __TEXT,__const section, but this
isn't good for UTF16 strings. The __ustring section allows for coalescing, among
other niceties (such as allowing the linker to easily split up strings).
Instead of outputting the UTF16 string as a series of bytes, output it as a
series of shorts. The back-end will then nicely place the UTF16 string into the
correct section, because it's a mensch.
<rdar://problem/10655949>
llvm-svn: 153710
Rafael Espindola