[mach-o] parse multiple symbols on same address into aliases

llvm-svn: 210502

2 files changed, 101 insertions, 2 deletions

diff --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp b/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
index e5ce190f924..3ea49a4ac16 100644
--- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
+++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
@@ -254,10 +254,19 @@ error_code processSymboledSection(DefinedAtom::ContentType atomType,
   appendSymbolsInSection(normalizedFile.globalSymbols, sectIndex, symbols);
   appendSymbolsInSection(normalizedFile.localSymbols,  sectIndex, symbols);
 
-  // Sort symbols by address.
+  // Sort symbols.
   std::sort(symbols.begin(), symbols.end(),
             [](const Symbol *lhs, const Symbol *rhs) -> bool {
-              return lhs->value < rhs->value;
+              // First by address.
+              if (lhs->value != rhs->value)
+                return lhs->value < rhs->value;
+              // If same address, one is an alias.  Sort by scope.
+              Atom::Scope lScope = atomScope(lhs->scope);
+              Atom::Scope rScope = atomScope(rhs->scope);
+              if (lScope != rScope)
+                return lScope < rScope;
+              // If same address and scope, sort by name.   
+              return (lhs->name.compare(rhs->name) < 1);
             });
 
   // Debug logging of symbols.
diff --git a/lld/test/mach-o/parse-aliases.yaml b/lld/test/mach-o/parse-aliases.yaml
new file mode 100644
index 00000000000..457ea58133b
--- /dev/null
+++ b/lld/test/mach-o/parse-aliases.yaml
@@ -0,0 +1,90 @@
+# RUN: lld -flavor darwin -arch x86_64 -r -print_atoms %s -o %t  | FileCheck %s
+#
+# Test multiple labels to same address parse into aliases.
+#
+
+--- !mach-o
+arch:            x86_64
+file-type:       MH_OBJECT
+flags:           [ MH_SUBSECTIONS_VIA_SYMBOLS ]
+has-UUID:        false
+OS:              unknown
+sections:
+  - segment:         __TEXT
+    section:         __text
+    type:            S_REGULAR
+    attributes:      [ S_ATTR_PURE_INSTRUCTIONS, S_ATTR_SOME_INSTRUCTIONS ]
+    alignment:       4
+    address:         0x0000000000000000
+    content:         [ 0xCC, 0xC3 ]
+local-symbols:
+  - name:            _pad
+    type:            N_SECT
+    scope:           [ N_EXT ]
+    sect:            1
+    value:           0x0000000000000000
+  - name:            _myStaticAlias1
+    type:            N_SECT
+    sect:            1
+    value:           0x0000000000000001
+  - name:            _myStaticAlias3
+    type:            N_SECT
+    sect:            1
+    value:           0x0000000000000001
+  - name:            _myStaticAlias2
+    type:            N_SECT
+    sect:            1
+    value:           0x0000000000000001
+global-symbols:
+  - name:            _myGlobalFunc1
+    type:            N_SECT
+    scope:           [ N_EXT ]
+    sect:            1
+    value:           0x0000000000000001
+  - name:            _myGlobalFunc2
+    type:            N_SECT
+    scope:           [ N_EXT ]
+    sect:            1
+    value:           0x0000000000000001
+  - name:            _myGlobalFunc3
+    type:            N_SECT
+    scope:           [ N_EXT ]
+    sect:            1
+    value:           0x0000000000000001
+  - name:            _myHiddenAlias1
+    type:            N_SECT
+    scope:           [ N_EXT, N_PEXT ]
+    sect:            1
+    value:           0x0000000000000001
+  - name:            _myHiddenAlias2
+    type:            N_SECT
+    scope:           [ N_EXT, N_PEXT ]
+    sect:            1
+    value:           0x0000000000000001
+  - name:            _myHiddenAlias3
+    type:            N_SECT
+    scope:           [ N_EXT, N_PEXT ]
+    sect:            1
+    value:           0x0000000000000001
+...
+
+# CHECK: defined-atoms:   
+# CHECK:   - name:            _pad
+# CHECK:     scope:           global
+# CHECK:     content:         [ CC ]
+# CHECK:   - name:            _myStaticAlias1
+# CHECK:   - name:            _myStaticAlias2
+# CHECK:   - name:            _myStaticAlias3
+# CHECK:   - name:            _myHiddenAlias1
+# CHECK:     scope:           hidden
+# CHECK:   - name:            _myHiddenAlias2
+# CHECK:     scope:           hidden
+# CHECK:   - name:            _myHiddenAlias3
+# CHECK:     scope:           hidden
+# CHECK:   - name:            _myGlobalFunc1
+# CHECK:     scope:           global
+# CHECK:   - name:            _myGlobalFunc2
+# CHECK:     scope:           global
+# CHECK:   - name:            _myGlobalFunc3
+# CHECK:     scope:           global
+# CHECK:     content:         [ C3 ]