[PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

[Yaxun Liu via cfe-commits]

yaxunl added a comment.

Thanks for your comments.

It works like this, e.g.

$ cat prog.ll
declare i32 @foo()

define void @use_foo() {

  %a = call i32 @foo()
  ret void

}

$ cat lib_common.ll
define linkonce_odr i32 @foo() {

  ret i32 1;

}

$ cat lib_opt.ll
define linkonce_odr i32 @foo() {

  ret i32 2;

}

$ llvm-link prog.ll lib_common.ll -override lib_opt.ll -S
; ModuleID = 'llvm-link'

define void @use_foo() {

  %a = call i32 @foo()
  ret void

}

define linkonce_odr i32 @foo() {

  ret i32 2

}

We can put all common functions in lib_common.ll, then only put a subset in lib_opt.ll. Functions in lib_opt.ll will override functions in lib_common.ll. For different GPUs we provide different lib_opt.ll. Each GPU may override different subset of lib_common.ll.

We use __attribute__((linkonce_odr_linkage)) by following the precedence of __attribute__((internal_linkage)) which exposes the LLVM internal_linkage to C/C++ programmers. We would like to accept suggestions for a better way to expose the linkonce_odr linkage.


Repository:
  rL LLVM

http://reviews.llvm.org/D18095