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[ELF] - Fix case of using both --icf and --symbol-ordering-file together. 

Imagine that we have sections A, B, C, where A == C and
symbol ordering file containing symbols: symC, symB, symA

Previously because of ICF it was possible that final order would be
B, A or B, C. That violates order specified in ordering file.
Patch changes that.

Differential revision: https://reviews.llvm.org/D43234

llvm-svn: 326179
This commit is contained in:
George Rimar 2018-02-27 08:26:38 +00:00
parent f268cd0aad
commit a77b963c90
2 changed files with 33 additions and 1 deletions
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2
lld/ELF/Writer.cpp
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@ -1056,7 +1056,7 @@ static DenseMap<const InputSectionBase *, int> buildSectionOrder() {
continue;
if (auto *Sec = dyn_cast_or_null<InputSectionBase>(D->Section)) {
int &Priority = SectionOrder[Sec];
int &Priority = SectionOrder[cast<InputSectionBase>(Sec->Repl)];
Priority = std::min(Priority, Ent.Priority);
}
}

32
lld/test/ELF/symbol-ordering-file-icf.s Normal file
View File

@ -0,0 +1,32 @@
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
# RUN: echo "zed" > %t.order
# RUN: echo "bar" >> %t.order
# RUN: echo "foo" >> %t.order
# RUN: ld.lld --icf=all --symbol-ordering-file %t.order -shared %t.o -o %t.so
# RUN: llvm-nm %t.so | FileCheck %s
## Check that after ICF merges 'foo' and 'zed' we still
## place them before 'bar', in according to ordering file.
# CHECK-DAG: 0000000000001000 T foo
# CHECK-DAG: 0000000000001000 T zed
# CHECK-DAG: 0000000000001004 T bar
.section .text.foo,"ax",@progbits
.align 4
.global foo
foo:
retq
.section .text.bar,"ax",@progbits
.align 4
.global bar
bar:
nop
retq
.section .text.zed,"ax",@progbits
.align 4
.global zed
zed:
retq