[dsymutil] Ignore absolute symbols in the debug map

Quoting from the comment added to the code:

    // Objective-C on i386 uses artificial absolute symbols to
    // perform some link time checks. Those symbols have a fixed 0
    // address that might conflict with real symbols in the object
    // file. As I cannot see a way for absolute symbols to find
    // their way into the debug information, let's just ignore those.

llvm-svn: 255350

3 files changed, 16 insertions, 0 deletions

diff --git a/llvm/test/tools/dsymutil/Inputs/absolute_sym.macho.i386 b/llvm/test/tools/dsymutil/Inputs/absolute_sym.macho.i386
new file mode 100755
index 00000000000..5ca0f2d6868
--- /dev/null
+++ b/llvm/test/tools/dsymutil/Inputs/absolute_sym.macho.i386
diff --git a/llvm/test/tools/dsymutil/Inputs/absolute_sym.macho.i386.o b/llvm/test/tools/dsymutil/Inputs/absolute_sym.macho.i386.o
new file mode 100644
index 00000000000..445e32271cf
--- /dev/null
+++ b/llvm/test/tools/dsymutil/Inputs/absolute_sym.macho.i386.o
diff --git a/llvm/test/tools/dsymutil/absolute_symbol.test b/llvm/test/tools/dsymutil/absolute_symbol.test
new file mode 100644
index 00000000000..cdd6ae83213
--- /dev/null
+++ b/llvm/test/tools/dsymutil/absolute_symbol.test
@@ -0,0 +1,16 @@
+RUN: llvm-dsymutil -dump-debug-map -oso-prepend-path %p %p/Inputs/absolute_sym.macho.i386 | FileCheck %s
+
+The tested object file has been created by the dummy Objective-C code:
+@interface Foo
+@end
+
+@implementation Foo
+@end
+
+int main() { return 0; }
+
+compiled for i386. This create an absolute symbol .objc_class_name_Foo
+We must not consider this symbol for debug info linking as its address
+might conflict with other real symbols in the same file.
+
+CHECK-NOT: objc_class_name_Foo