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authorTom Stellard <tstellar@redhat.com>2018-10-31 17:14:17 +0000
committerTom Stellard <tstellar@redhat.com>2018-10-31 17:14:17 +0000
commitb9f34e3a65782a9f33fe9eaf2240ec4f1f6e3f6e (patch)
tree86a9f12e073bf610283641d1ecbbc8dc1aaa03c8
parent22d86791526b83733a51b107c70e68a54fbd3370 (diff)
Merging r345002:release_70
------------------------------------------------------------------------ r345002 | dim | 2018-10-22 22:53:15 -0700 (Mon, 22 Oct 2018) | 41 lines Don't mess up RelIplt symbols during relocatable processing Summary: During upgrading of the FreeBSD source tree with lld 7.0.0, I noticed that it started complaining about `crt1.o` having an "index past the end of the symbol table". Such a symbol table looks approximately like this, viewed with `readelf -s` (note the `Ndx` field being messed up): ``` Symbol table '.symtab' contains 4 entries: Num: Value Size Type Bind Vis Ndx Name 0: 00000000 0 NOTYPE LOCAL DEFAULT UND 1: 00000000 0 SECTION LOCAL DEFAULT 1 2: 00000000 0 NOTYPE WEAK HIDDEN RSV[0xffff] __rel_iplt_end 3: 00000000 0 NOTYPE WEAK HIDDEN RSV[0xffff] __rel_iplt_start ``` At first, it seemed that recent ifunc relocation work had caused this: <https://reviews.freebsd.org/rS339351>, but it turned out that it was due to incorrect processing of the object files by lld, when using `-r` (a.k.a. --relocatable). Bisecting showed that rL324421 ("Convert a use of Config->Static") was the commit where this new behavior began. Simply reverting it solved the issue, and the `__rel_iplt` symbols had an index of `UND` again. Looking at Rafael's commit message, I think he simply missed the possibility of `--relocatable` being in effect, so I have added an additional check for it. I also added a simple regression test case. Reviewers: grimar, ruiu, emaste, espindola Reviewed By: ruiu Subscribers: arichardson, krytarowski, llvm-commits Differential Revision: https://reviews.llvm.org/D53515 ------------------------------------------------------------------------ git-svn-id: https://llvm.org/svn/llvm-project/lld/branches/release_70@345739 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r--ELF/Writer.cpp2
-rw-r--r--test/ELF/relocatable-rel-iplt.s56
2 files changed, 57 insertions, 1 deletions
diff --git a/ELF/Writer.cpp b/ELF/Writer.cpp
index 88a2d5c71..09a17049f 100644
--- a/ELF/Writer.cpp
+++ b/ELF/Writer.cpp
@@ -874,7 +874,7 @@ void PhdrEntry::add(OutputSection *Sec) {
// need these symbols, since IRELATIVE relocs are resolved through GOT
// and PLT. For details, see http://www.airs.com/blog/archives/403.
template <class ELFT> void Writer<ELFT>::addRelIpltSymbols() {
- if (needsInterpSection())
+ if (Config->Relocatable || needsInterpSection())
return;
StringRef S = Config->IsRela ? "__rela_iplt_start" : "__rel_iplt_start";
addOptionalRegular(S, InX::RelaIplt, 0, STV_HIDDEN, STB_WEAK);
diff --git a/test/ELF/relocatable-rel-iplt.s b/test/ELF/relocatable-rel-iplt.s
new file mode 100644
index 000000000..773a09f52
--- /dev/null
+++ b/test/ELF/relocatable-rel-iplt.s
@@ -0,0 +1,56 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=i686-- %s -o %t1.o
+# RUN: ld.lld -r %t1.o -o %t2.o
+# RUN: llvm-readobj -t %t2.o | FileCheck %s
+
+// CHECK: Symbols [
+// CHECK-NEXT: Symbol {
+// CHECK-NEXT: Name: (0)
+// CHECK-NEXT: Value: 0x0
+// CHECK-NEXT: Size: 0
+// CHECK-NEXT: Binding: Local (0x0)
+// CHECK-NEXT: Type: None (0x0)
+// CHECK-NEXT: Other: 0
+// CHECK-NEXT: Section: Undefined (0x0)
+// CHECK-NEXT: }
+// CHECK-NEXT: Symbol {
+// CHECK-NEXT: Name: (0)
+// CHECK-NEXT: Value: 0x0
+// CHECK-NEXT: Size: 0
+// CHECK-NEXT: Binding: Local (0x0)
+// CHECK-NEXT: Type: Section (0x3)
+// CHECK-NEXT: Other: 0
+// CHECK-NEXT: Section: .text (0x1)
+// CHECK-NEXT: }
+// CHECK-NEXT: Symbol {
+// CHECK-NEXT: Name: __rel_iplt_end (1)
+// CHECK-NEXT: Value: 0x0
+// CHECK-NEXT: Size: 0
+// CHECK-NEXT: Binding: Weak (0x2)
+// CHECK-NEXT: Type: None (0x0)
+// CHECK-NEXT: Other [ (0x2)
+// CHECK-NEXT: STV_HIDDEN (0x2)
+// CHECK-NEXT: ]
+// CHECK-NEXT: Section: Undefined (0x0)
+// CHECK-NEXT: }
+// CHECK-NEXT: Symbol {
+// CHECK-NEXT: Name: __rel_iplt_start (16)
+// CHECK-NEXT: Value: 0x0
+// CHECK-NEXT: Size: 0
+// CHECK-NEXT: Binding: Weak (0x2)
+// CHECK-NEXT: Type: None (0x0)
+// CHECK-NEXT: Other [ (0x2)
+// CHECK-NEXT: STV_HIDDEN (0x2)
+// CHECK-NEXT: ]
+// CHECK-NEXT: Section: Undefined (0x0)
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+
+ movl __rel_iplt_start, %eax
+ movl __rel_iplt_end, %eax
+ ret
+
+ .hidden __rel_iplt_start
+ .hidden __rel_iplt_end
+ .weak __rel_iplt_start
+ .weak __rel_iplt_end