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ELF: Allow -e <entry> with -shared 

It is reasonable to specify an entry point for shared objects - for
example, for the FreeBSD rtld ld-elf.so.1.

Unlike GNU ld we leave the entry address as 0 if -shared is specified
without -e.

Differential Revision:	http://reviews.llvm.org/D15454

llvm-svn: 255349
This commit is contained in:
Ed Maste 2015-12-11 17:46:46 +00:00
parent 494393b740
commit f2ac688217
2 changed files with 10 additions and 5 deletions
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12
lld/ELF/Driver.cpp
View File

@ -248,11 +248,6 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
if (Config->Entry.empty())
Config->Entry = (Config->EMachine == EM_MIPS) ? "__start" : "_start";
// Set either EntryAddr (if S is a number) or EntrySym (otherwise).
StringRef S = Config->Entry;
if (S.getAsInteger(0, Config->EntryAddr))
Config->EntrySym = Symtab.addUndefined(S);
// In the assembly for 32 bit x86 the _GLOBAL_OFFSET_TABLE_ symbol
// is magical and is used to produce a R_386_GOTPC relocation.
// The R_386_GOTPC relocation value doesn't actually depend on the
@ -268,6 +263,13 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
Symtab.addIgnoredSym("_GLOBAL_OFFSET_TABLE_");
}
if (!Config->Entry.empty()) {
// Set either EntryAddr (if S is a number) or EntrySym (otherwise).
StringRef S = Config->Entry;
if (S.getAsInteger(0, Config->EntryAddr))
Config->EntrySym = Symtab.addUndefined(S);
}
// Define _gp for MIPS. st_value of _gp symbol will be updated by Writer
// so that it points to an absolute address which is relative to GOT.
// See "Global Data Symbols" in Chapter 6 in the following document:

3
lld/test/ELF/entry.s
View File

@ -2,6 +2,8 @@
# RUN: not ld.lld %t1 -o %t2
# RUN: ld.lld %t1 -o %t2 -e entry
# RUN: llvm-readobj -file-headers %t2 | FileCheck -check-prefix=SYM %s
# RUN: ld.lld %t1 -shared -o %t2 -e entry
# RUN: llvm-readobj -file-headers %t2 | FileCheck -check-prefix=DSO %s
# RUN: ld.lld %t1 -o %t2 -e 4096
# RUN: llvm-readobj -file-headers %t2 | FileCheck -check-prefix=DEC %s
# RUN: ld.lld %t1 -o %t2 -e 0xcafe
@ -10,6 +12,7 @@
# RUN: llvm-readobj -file-headers %t2 | FileCheck -check-prefix=OCT %s
# SYM: Entry: 0x11000
# DSO: Entry: 0x1000
# DEC: Entry: 0x1000
# HEX: Entry: 0xCAFE
# OCT: Entry: 0x1FF