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[ELF] - Don't segfault when assigning non-calculatable absolute symbol value. 

This is PR32664.

Issue was revealed by linux kernel script which was:

SECTIONS {
 . = (0xffffffff80000000 + ALIGN(0x1000000, 0x200000));
 phys_startup_64 = ABSOLUTE(startup_64 - 0xffffffff80000000);

 .text : AT(ADDR(.text) - 0xffffffff80000000) {
.....
  *(.head.text)
Where startup_64 is in .head.text.

At the place of assignment to phys_startup_64 we can not calculate absolute value for startup_64
because .text section has no VA assigned. Two patches were prepared earlier to address this: D32173 and D32174.

And in comments for D32173 was suggested not try to support this case, but error out.

Differential revision: https://reviews.llvm.org/D32793

llvm-svn: 302668
This commit is contained in:
George Rimar 2017-05-10 14:23:33 +00:00
parent 93b369ed11
commit 608cf67084
2 changed files with 20 additions and 2 deletions
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8
lld/ELF/LinkerScript.cpp
View File

@ -48,8 +48,12 @@ using namespace lld::elf;
LinkerScript *elf::Script;
uint64_t ExprValue::getValue() const {
if (Sec)
return Sec->getOffset(Val) + Sec->getOutputSection()->Addr;
if (Sec) {
if (Sec->getOutputSection())
return Sec->getOffset(Val) + Sec->getOutputSection()->Addr;
error("unable to evaluate expression: input section " + Sec->Name +
" has no output section assigned");
}
return Val;
}

14
lld/test/ELF/linkerscript/early-assign-symbol.s Normal file
View File

@ -0,0 +1,14 @@
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
# RUN: echo "SECTIONS { aaa = 1 + ABSOLUTE(foo - 1); }" > %t1.script
# RUN: not ld.lld -o %t --script %t1.script %t.o 2>&1 | FileCheck %s
# RUN: echo "SECTIONS { aaa = ABSOLUTE(foo - 1) + 1; }" > %t2.script
# RUN: not ld.lld -o %t --script %t2.script %t.o 2>&1 | FileCheck %s
# CHECK: error: unable to evaluate expression: input section .text has no output section assigned
.section .text
.globl foo
foo: