[lld] r255349 - ELF: Allow -e <entry> with -shared

[Ed Maste via llvm-commits]

Author: emaste
Date: Fri Dec 11 11:46:46 2015
New Revision: 255349

URL: http://llvm.org/viewvc/llvm-project?rev=255349&view=rev
Log:
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

Modified:
    lld/trunk/ELF/Driver.cpp
    lld/trunk/test/ELF/entry.s

Modified: lld/trunk/ELF/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Driver.cpp?rev=255349&r1=255348&r2=255349&view=diff
==============================================================================
--- lld/trunk/ELF/Driver.cpp (original)
+++ lld/trunk/ELF/Driver.cpp Fri Dec 11 11:46:46 2015
@@ -248,11 +248,6 @@ template <class ELFT> void LinkerDriver:
     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:
     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:

Modified: lld/trunk/test/ELF/entry.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/entry.s?rev=255349&r1=255348&r2=255349&view=diff
==============================================================================
--- lld/trunk/test/ELF/entry.s (original)
+++ lld/trunk/test/ELF/entry.s Fri Dec 11 11:46:46 2015
@@ -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