From c0d4e00b35409c757f0d240bafe69d7c7cdf2c3d Mon Sep 17 00:00:00 2001
From: Wolfgang Thaller <wolfgang.thaller@gmx.net>
Date: Sat, 9 Dec 2023 11:37:32 +0100
Subject: [PATCH] add LocalStatic test case

---
 AutomatedTests/CMakeLists.txt |  3 ++
 AutomatedTests/LocalStatic.cc | 61 +++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)
 create mode 100644 AutomatedTests/LocalStatic.cc

diff --git a/AutomatedTests/CMakeLists.txt b/AutomatedTests/CMakeLists.txt
index c79aedb75a..cef0494c5a 100644
--- a/AutomatedTests/CMakeLists.txt
+++ b/AutomatedTests/CMakeLists.txt
@@ -90,3 +90,6 @@ test(${CMAKE_CURRENT_BINARY_DIR}/PascalTrapCPP.cc PROPERTIES PASS_REGULAR_EXPRES
 configure_file(PascalString.c PascalStringCPP.cc)
 test(PascalString.c PROPERTIES PASS_REGULAR_EXPRESSION "OK")
 test(${CMAKE_CURRENT_BINARY_DIR}/PascalStringCPP.cc PROPERTIES PASS_REGULAR_EXPRESSION "OK")
+
+test(LocalStatic.cc PROPERTIES PASS_REGULAR_EXPRESSION "OK")
+set_target_properties(LocalStatic PROPERTIES COMPILE_FLAGS -fno-exceptions) # just to make assembly easier to read
diff --git a/AutomatedTests/LocalStatic.cc b/AutomatedTests/LocalStatic.cc
new file mode 100644
index 0000000000..3556f85c43
--- /dev/null
+++ b/AutomatedTests/LocalStatic.cc
@@ -0,0 +1,61 @@
+#include "Test.h"
+
+/*
+ 
+This test case is intended to check for one particular binutils/xcoff problem:
+
+Without a patch, GNU ld fails to allocate space for weak uninitialized csects [BS],
+and therefore puts both at the same address.
+
+Minimal example:
+
+	.weak	_one[BS]
+	.csect _one[BS]
+_one:
+	.space 4
+	.weak	_two[BS]
+	.csect _two[BS]
+_two:
+	.space 4
+
+ 
+powerpc-apple-macos-as test.s > test.o
+powerpc-apple-macos-ld -r test.o -o linked.o
+powerpc-apple-macos-objdump -t -h linked.o
+
+Observe the size of the .bss section and the addresses of symbols _one and _two.
+
+This test case tests for it using a thread-safe local static variable in an inline
+function, which boils down to a pair of weakly-linked uninitialized csects as above.
+
+ */
+
+
+// noinline so that it doesn't get optimized away
+__attribute__((noinline)) int foo()
+{
+    return 42;
+}
+
+// the `inline` triggers a problem.
+// the static var and its guard variable are marked `.weak`,
+// and the XCOFF linker puts them at the same address.
+inline int bar()
+{
+    static int cachedFoo = foo();
+    return cachedFoo;
+}
+
+// wrap it in a noinline function to make reading the assembly easier.
+ __attribute__((noinline)) int baz()
+{
+    return bar();
+}
+
+int main()
+{
+    if (baz() != 42)
+        TestLog("NO");
+    else
+        TestLog("OK");
+}