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
llvm-svn: 345002
2018-10-23 13:53:15 +08:00
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# REQUIRES: x86
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# RUN: llvm-mc -filetype=obj -triple=i686-- %s -o %t1.o
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# RUN: ld.lld -r %t1.o -o %t2.o
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# RUN: llvm-readobj -t %t2.o | FileCheck %s
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// CHECK: Symbols [
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// CHECK-NEXT: Symbol {
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// CHECK-NEXT: Name: (0)
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// CHECK-NEXT: Value: 0x0
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// CHECK-NEXT: Size: 0
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// CHECK-NEXT: Binding: Local (0x0)
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// CHECK-NEXT: Type: None (0x0)
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// CHECK-NEXT: Other: 0
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// CHECK-NEXT: Section: Undefined (0x0)
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// CHECK-NEXT: }
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// CHECK-NEXT: Symbol {
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2019-03-02 02:01:41 +08:00
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// CHECK-NEXT: Name: .text (0)
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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
llvm-svn: 345002
2018-10-23 13:53:15 +08:00
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// CHECK-NEXT: Value: 0x0
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// CHECK-NEXT: Size: 0
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// CHECK-NEXT: Binding: Local (0x0)
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// CHECK-NEXT: Type: Section (0x3)
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// CHECK-NEXT: Other: 0
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// CHECK-NEXT: Section: .text (0x1)
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// CHECK-NEXT: }
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// CHECK-NEXT: Symbol {
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// CHECK-NEXT: Name: __rel_iplt_end (1)
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// CHECK-NEXT: Value: 0x0
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// CHECK-NEXT: Size: 0
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// CHECK-NEXT: Binding: Weak (0x2)
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// CHECK-NEXT: Type: None (0x0)
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// CHECK-NEXT: Other [ (0x2)
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// CHECK-NEXT: STV_HIDDEN (0x2)
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// CHECK-NEXT: ]
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// CHECK-NEXT: Section: Undefined (0x0)
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// CHECK-NEXT: }
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// CHECK-NEXT: Symbol {
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// CHECK-NEXT: Name: __rel_iplt_start (16)
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// CHECK-NEXT: Value: 0x0
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// CHECK-NEXT: Size: 0
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// CHECK-NEXT: Binding: Weak (0x2)
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// CHECK-NEXT: Type: None (0x0)
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// CHECK-NEXT: Other [ (0x2)
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// CHECK-NEXT: STV_HIDDEN (0x2)
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// CHECK-NEXT: ]
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// CHECK-NEXT: Section: Undefined (0x0)
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// CHECK-NEXT: }
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// CHECK-NEXT: ]
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movl __rel_iplt_start, %eax
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movl __rel_iplt_end, %eax
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ret
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.hidden __rel_iplt_start
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.hidden __rel_iplt_end
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.weak __rel_iplt_start
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.weak __rel_iplt_end
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