llvm/test/ThinLTO/X86/odr_resolution.ll
Mehdi Amini 03669a56fb ThinLTO: special handling for LinkOnce functions
These function can be dropped by the compiler if they are no longer
referenced in the current module. However there is a change that
another module is still referencing them because of the import.

Multiple solutions can be used:

- Always import LinkOnce when a caller is imported. This ensure that
  every module with a call to a LinkOnce has the definition and will
  be able to emit it if it emits the call.
- Turn the LinkOnce into Weak, so that it is always emitted.
- Turn all LinkOnce into available_externally and come back after all
  modules are codegen'ed to emit only one copy of the linkonce, when
  there is still a reference to it.

This patch implement the second option, with am optimization that
only *one* module will turn the LinkOnce into Weak, while the others
will turn it into available_externally, so that there is exactly one
copy emitted for the whole compilation.

http://reviews.llvm.org/D18346

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265190 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-01 21:53:50 +00:00

51 lines
1.8 KiB
LLVM

; Do setup work for all below tests: generate bitcode and combined index
; RUN: llvm-as -module-summary %s -o %t.bc
; RUN: llvm-as -module-summary %p/Inputs/odr_resolution.ll -o %t2.bc
; RUN: llvm-lto -thinlto-action=thinlink -o %t3.bc %t.bc %t2.bc
; Verify that only one ODR is selected across modules, but non ODR are not affected.
; RUN: llvm-lto -thinlto-action=promote %t.bc -thinlto-index=%t3.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=MOD1
; RUN: llvm-lto -thinlto-action=promote %t2.bc -thinlto-index=%t3.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=MOD2
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.11.0"
; Alias are not optimized
; MOD1: @linkoncealias = linkonce_odr alias void (), void ()* @linkonceodrfuncwithalias
; MOD2: @linkoncealias = linkonce_odr alias void (), void ()* @linkonceodrfuncwithalias
@linkoncealias = linkonce_odr alias void (), void ()* @linkonceodrfuncwithalias
; Function with an alias are not optimized
; MOD1: define linkonce_odr void @linkonceodrfuncwithalias()
; MOD2: define linkonce_odr void @linkonceodrfuncwithalias()
define linkonce_odr void @linkonceodrfuncwithalias() #0 {
entry:
ret void
}
; MOD1: define weak_odr void @linkonceodrfunc()
; MOD2: define available_externally void @linkonceodrfunc()
define linkonce_odr void @linkonceodrfunc() #0 {
entry:
ret void
}
; MOD1: define linkonce void @linkoncefunc()
; MOD2: define linkonce void @linkoncefunc()
define linkonce void @linkoncefunc() #0 {
entry:
ret void
}
; MOD1: define weak_odr void @weakodrfunc()
; MOD2: define available_externally void @weakodrfunc()
define weak_odr void @weakodrfunc() #0 {
entry:
ret void
}
; MOD1: define weak void @weakfunc()
; MOD2: define weak void @weakfunc()
define weak void @weakfunc() #0 {
entry:
ret void
}