maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

ELF: Add libcall symbols to the link when LTO is being used. 

If any of our inputs are bitcode files, the LTO code generator may create
references to certain library functions that might not be explicit in the
bitcode file's symbol table. If any of those library functions are defined
in a bitcode file in an archive member, we need to arrange to use LTO to
compile those archive members by adding them to the link beforehand.

Differential Revision: https://reviews.llvm.org/D50017

llvm-svn: 338434
This commit is contained in:
Peter Collingbourne 2018-07-31 20:36:17 +00:00
parent bb1078ad85
commit 2da4e52182
3 changed files with 45 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
lld/ELF/Driver.cpp
View File

@ -1313,6 +1313,12 @@ static void findKeepUniqueSections(opt::InputArgList &Args) {
} }
} }
static const char *LibcallRoutineNames[] = {
#define HANDLE_LIBCALL(code, name) name,
#include "llvm/IR/RuntimeLibcalls.def"
#undef HANDLE_LIBCALL
};
// Do actual linking. Note that when this function is called, // Do actual linking. Note that when this function is called,
// all linker scripts have already been parsed. // all linker scripts have already been parsed.
template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) { template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
@ -1379,11 +1385,21 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
for (StringRef S : Config->Undefined) for (StringRef S : Config->Undefined)
handleUndefined<ELFT>(S); handleUndefined<ELFT>(S);
// If an entry symbol is in a static archive, pull out that file now // If an entry symbol is in a static archive, pull out that file now.
// to complete the symbol table. After this, no new names except a
// few linker-synthesized ones will be added to the symbol table.
handleUndefined<ELFT>(Config->Entry); handleUndefined<ELFT>(Config->Entry);
// If any of our inputs are bitcode files, the LTO code generator may create
// references to certain library functions that might not be explicit in the
// bitcode file's symbol table. If any of those library functions are defined
// in a bitcode file in an archive member, we need to arrange to use LTO to
// compile those archive members by adding them to the link beforehand.
//
// With this the symbol table should be complete. After this, no new names
// except a few linker-synthesized ones will be added to the symbol table.
if (!BitcodeFiles.empty())
for (const char *S : LibcallRoutineNames)
handleUndefined<ELFT>(S);
// Return if there were name resolution errors. // Return if there were name resolution errors.
if (errorCount()) if (errorCount())
return; return;

6
lld/test/ELF/lto/Inputs/libcall-archive.ll Normal file
View File

@ -0,0 +1,6 @@
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define void @memcpy() {
ret void
}

20
lld/test/ELF/lto/libcall-archive.ll Normal file
View File

@ -0,0 +1,20 @@
; RUN: rm -f %t.a
; RUN: llvm-as -o %t.o %s
; RUN: llvm-as -o %t2.o %S/Inputs/libcall-archive.ll
; RUN: llvm-ar rcs %t.a %t2.o
; RUN: ld.lld -o %t %t.o %t.a
; RUN: llvm-nm %t | FileCheck %s
; CHECK: T _start
; CHECK: T memcpy
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define void @_start(i8* %a, i8* %b) {
entry:
call void @llvm.memcpy.p0i8.p0i8.i64(i8* %a, i8* %b, i64 1024, i1 false)
ret void
}
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i1)