rust: Fix rust modules test

I noticed that the modules test was failing. Some choice use of `nm`
revealed `TWENTY_THREE` was not in the final binary. Fix by taking a
pointer to the global, forcing the linker to keep the symbol in.

gdb/testsuite/ChangeLog
2020-07-11  Daniel Xu  <dxu@dxuuu.xyz>

	PR rust/26121
	* gdb.rust/modules.rs: Prevent linker from discarding test
	symbol.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index c0f1f1cc14c3c50a414823aeaab35b09a7d3b93f..ec0f8322e32722d76b3ddc0cc377cfeb2bea69f9 100644 (file)
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2020-07-11  Daniel Xu  <dxu@dxuuu.xyz>
+
+       PR rust/26121
+       * gdb.rust/modules.rs: Prevent linker from discarding test
+       symbol.
+
 2020-07-10  Pedro Alves  <pedro@palves.net>
 
        PR gdb/26199

diff --git a/gdb/testsuite/gdb.rust/modules.rs b/gdb/testsuite/gdb.rust/modules.rs
index 6db082817b531c2af96682ad9cd507d25802b8c1..479e6529cdca3bc36d3d943e9da984d7dbf8f86b 100644 (file)
--- a/gdb/testsuite/gdb.rust/modules.rs
+++ b/gdb/testsuite/gdb.rust/modules.rs
@@ -60,7 +60,8 @@ pub mod mod1 {
 
                 let f2 = || println!("lambda f2");
 
-                let copy = ::TWENTY_THREE;
+                // Prevent linker from discarding symbol
+                let ptr: *const u16 = &::TWENTY_THREE;
 
                 f2();           // set breakpoint here
                 f3();