[lld] r176310 - [ELF][x86-64] Only emit a PLT entry for a PLT relocation if the target atom is a SharedLibraryAtom.

[Michael J. Spencer]

Author: mspencer
Date: Thu Feb 28 18:03:56 2013
New Revision: 176310

URL: http://llvm.org/viewvc/llvm-project?rev=176310&view=rev
Log:
[ELF][x86-64] Only emit a PLT entry for a PLT relocation if the target atom is a SharedLibraryAtom.

This seems to be what ld does, but I'm not sure how it works with symbol interposition.

With this hello-world with glibc dynamically linked works.

Added:
    lld/trunk/test/elf/Inputs/relocs-dynamic.x86-64
    lld/trunk/test/elf/Inputs/x86-64-relocs.S
    lld/trunk/test/elf/x86-64-dynamic-relocs.test
Modified:
    lld/trunk/lib/ReaderWriter/ELF/X86_64/X86_64TargetInfo.cpp

Modified: lld/trunk/lib/ReaderWriter/ELF/X86_64/X86_64TargetInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/X86_64/X86_64TargetInfo.cpp?rev=176310&r1=176309&r2=176310&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/ELF/X86_64/X86_64TargetInfo.cpp (original)
+++ lld/trunk/lib/ReaderWriter/ELF/X86_64/X86_64TargetInfo.cpp Thu Feb 28 18:03:56 2013
@@ -399,7 +399,8 @@ public:
     if (const DefinedAtom *da = dyn_cast_or_null<const DefinedAtom>(ref.target()))
       if (da->contentType() == DefinedAtom::typeResolver)
         return handleIFUNC(ref);
-    const_cast<Reference &>(ref).setTarget(getPLTEntry(ref.target()));
+    if (isa<const SharedLibraryAtom>(ref.target()))
+      const_cast<Reference &>(ref).setTarget(getPLTEntry(ref.target()));
     return error_code::success();
   }
 

Added: lld/trunk/test/elf/Inputs/relocs-dynamic.x86-64
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf/Inputs/relocs-dynamic.x86-64?rev=176310&view=auto
==============================================================================
Binary files lld/trunk/test/elf/Inputs/relocs-dynamic.x86-64 (added) and lld/trunk/test/elf/Inputs/relocs-dynamic.x86-64 Thu Feb 28 18:03:56 2013 differ

Added: lld/trunk/test/elf/Inputs/x86-64-relocs.S
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf/Inputs/x86-64-relocs.S?rev=176310&view=auto
==============================================================================
--- lld/trunk/test/elf/Inputs/x86-64-relocs.S (added)
+++ lld/trunk/test/elf/Inputs/x86-64-relocs.S Thu Feb 28 18:03:56 2013
@@ -0,0 +1,12 @@
+        .text
+        .globl  main
+        .align  16, 0x90
+        .type   main, at function
+main:                                   # @main
+        call foo at PLT
+        ret
+
+        .globl foo
+        .type foo, at function
+foo:
+        ret

Added: lld/trunk/test/elf/x86-64-dynamic-relocs.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf/x86-64-dynamic-relocs.test?rev=176310&view=auto
==============================================================================
--- lld/trunk/test/elf/x86-64-dynamic-relocs.test (added)
+++ lld/trunk/test/elf/x86-64-dynamic-relocs.test Thu Feb 28 18:03:56 2013
@@ -0,0 +1,26 @@
+RUN: lld -core -target x86_64-linux %p/Inputs/relocs-dynamic.x86-64 -emit-yaml \
+RUN:   -output=- -noinhibit-exec -output-type=dynamic | FileCheck %s
+
+path:            <linker-internal>
+defined-atoms:
+  - name:            main
+    scope:           global
+    content:         [ E8, 00, 00, 00, 00, C3 ]
+    alignment:       2^4
+    section-choice:  custom-required
+    section-name:    .text
+    references:
+      - kind:            R_X86_64_PLT32
+        offset:          1
+        target:          foo
+        addend:          -4
+  - name:            foo
+    scope:           global
+    content:         [ C3 ]
+    alignment:       6 mod 2^4
+    section-choice:  custom-required
+    section-name:    .text
+
+# Don't generate a PLT/GOT entry for a PLT32 relocation to a non-shared symbol.
+CHECK-NOT: got
+CHECK-NOT: stub