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[lld][ELF] Handle multiple weak symbols 

This handles multiple weak symbols which appear back to back. This fix is needed
which otherwise will lead to symbols getting initialized to arbitrary values.

There was a constructor/destructor test that really triggered this to be fixed
on X86_64.

Adds a test.

llvm-svn: 190658
This commit is contained in:
Shankar Easwaran 2013-09-13 04:25:44 +00:00
parent 1bc22c12cb
commit 2a92c18ba3
5 changed files with 73 additions and 7 deletions
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13
lld/lib/ReaderWriter/ELF/File.h
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@ -428,19 +428,18 @@ public:
if (previousAtom)
createEdge(anonAtom, previousAtom,
lld::Reference::kindLayoutBefore);
// If this is the last atom, lets not create a followon reference.
if (anonAtom && (si + 1) != se) {
anonFollowedBy = new (_readerStorage) ELFReference<ELFT>(
lld::Reference::kindLayoutAfter);
anonAtom->addReference(anonFollowedBy);
}
}
ELFDefinedAtom<ELFT> *newAtom = createDefinedAtomAndAssignRelocations(
symbolName, *sectionName, &*symbol, section, symbolData);
newAtom->setOrdinal(++_ordinal);
// If this is the last atom, lets not create a followon reference.
if (anonAtom && (si + 1) != se) {
anonFollowedBy = new (_readerStorage)
ELFReference<ELFT>(lld::Reference::kindLayoutAfter);
anonAtom->addReference(anonFollowedBy);
}
// If the atom was a weak symbol, lets create a followon reference to
// the anonymous atom that we created.
if (anonAtom)

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lld/test/elf/X86_64/Inputs/multiweaksyms.o Normal file
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lld/test/elf/X86_64/Inputs/weak.o
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21
lld/test/elf/X86_64/Inputs/weak.s Normal file
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@ -0,0 +1,21 @@
.file "weak.s"
.text
.p2align 4,,15
.globl test
.type test, @function
test:
ret
.size test, .-test
.weak myfn2
.data
.align 8
.type myfn2, @object
.size myfn2, 8
myfn2:
.quad test
.weak myfn1
.align 8
.type myfn1, @object
.size myfn1, 8
myfn1:
.quad test

46
lld/test/elf/X86_64/multi-weak-layout.test Normal file
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@ -0,0 +1,46 @@
# Test that we are able to layout multiple weak symbols
# properly
RUN: lld -flavor gnu -target x86_64 %p/Inputs/multiweaksyms.o \
RUN: --noinhibit-exec -static -emit-yaml -o %t
RUN: FileCheck %s -check-prefix=WEAKSYMS < %t
WEAKSYMS: - ref-name: [[SYMA:[-a-zA-Z0-9_]+]]
WEAKSYMS: type: data
WEAKSYMS: references:
WEAKSYMS: - kind: layout-after
WEAKSYMS: target: [[SYMB:[-a-zA-Z0-9_]+]]
WEAKSYMS: - name: myfn2
WEAKSYMS: scope: global
WEAKSYMS: type: data
WEAKSYMS: merge: as-weak
WEAKSYMS: references:
WEAKSYMS: - kind: layout-after
WEAKSYMS: target: [[SYMB]]
WEAKSYMS: - ref-name: [[SYMB]]
WEAKSYMS: scope: global
WEAKSYMS: type: data
WEAKSYMS: content: [ 00, 00, 00, 00, 00, 00, 00, 00 ]
WEAKSYMS: references:
WEAKSYMS: - kind: R_X86_64_64
WEAKSYMS: target: test
WEAKSYMS: - kind: layout-before
WEAKSYMS: target: [[SYMA]]
WEAKSYMS: - kind: layout-after
WEAKSYMS: target: [[SYMC:[-a-zA-Z0-9_]+]]
WEAKSYMS: - name: myfn1
WEAKSYMS: scope: global
WEAKSYMS: type: data
WEAKSYMS: merge: as-weak
WEAKSYMS: references:
WEAKSYMS: - kind: layout-after
WEAKSYMS: target: [[SYMC]]
WEAKSYMS: - ref-name: [[SYMC]]
WEAKSYMS: scope: global
WEAKSYMS: type: data
WEAKSYMS: content: [ 00, 00, 00, 00, 00, 00, 00, 00 ]
WEAKSYMS: references:
WEAKSYMS: - kind: R_X86_64_64
WEAKSYMS: target: test
WEAKSYMS: - kind: layout-before
WEAKSYMS: target: [[SYMB]]