llvm-mirror/test/ThinLTO/X86/emit_imports.ll
Teresa Johnson 0f1566e03c [ThinLTO] Always emit a summary when compiling in ThinLTO mode
Summary:
Emit an empty summary section, instead of no summary section, when
there are no global variables in the index. This ensures that LTO
will treat these files as ThinLTO inputs, instead of as regular
LTO inputs.

In addition to not being what the user likely intended when
compiling with -flto=thin, the current behavior is problematic for
distributed build systems that expect to get ThinLTO index and imports
files back for each input compiled with -flto=thin. Combining into
a single regular LTO module also reduces the backend parallelism.
And in the case where the index was suppressed due to uses in
inline assembly, combining into a single LTO module could provoke
renaming of duplicates that we were trying to prevent by suppressing
the index.

This change required a couple of fixes to handle the empty summary
section.

Reviewers: mehdi_amini

Subscribers: mehdi_amini, llvm-commits, pcc

Differential Revision: https://reviews.llvm.org/D24779

llvm-svn: 282037
2016-09-20 23:07:17 +00:00

53 lines
1.9 KiB
LLVM

; RUN: opt -module-summary %s -o %t1.bc
; RUN: opt -module-summary %p/Inputs/emit_imports.ll -o %t2.bc
; Include a file with an empty module summary index, to ensure that the expected
; output files are created regardless, for a distributed build system.
; RUN: opt -module-summary %p/Inputs/empty.ll -o %t3.bc
; RUN: rm -f %t3.bc.imports
; RUN: llvm-lto -thinlto-action=thinlink -o %t.index.bc %t1.bc %t2.bc %t3.bc
; RUN: llvm-lto -thinlto-action=emitimports -thinlto-index %t.index.bc %t1.bc %t2.bc %t3.bc
; The imports file for this module contains the bitcode file for
; Inputs/emit_imports.ll
; RUN: cat %t1.bc.imports | count 1
; RUN: cat %t1.bc.imports | FileCheck %s --check-prefix=IMPORTS1
; IMPORTS1: emit_imports.ll.tmp2.bc
; The imports file for Input/emit_imports.ll is empty as it does not import anything.
; RUN: cat %t2.bc.imports | count 0
; The imports file for Input/empty.ll is empty but should exist.
; RUN: cat %t3.bc.imports | count 0
; RUN: rm -f %t1.thinlto.bc %t1.bc.imports
; RUN: rm -f %t2.thinlto.bc %t2.bc.imports
; RUN: rm -f %t3.bc.thinlto.bc %t3.bc.imports
; RUN: llvm-lto2 %t1.bc %t2.bc %t3.bc -o %t.o -save-temps \
; RUN: -thinlto-distributed-indexes \
; RUN: -r=%t1.bc,g, \
; RUN: -r=%t1.bc,f,px \
; RUN: -r=%t2.bc,g,px
; RUN: cat %t1.bc.imports | count 1
; RUN: cat %t1.bc.imports | FileCheck %s --check-prefix=IMPORTS1
; The imports file for Input/emit_imports.ll is empty as it does not import anything.
; RUN: cat %t2.bc.imports | count 0
; The imports file for Input/empty.ll is empty but should exist.
; RUN: cat %t3.bc.imports | count 0
; The index file should be created even for the input with an empty summary.
; RUN: ls %t3.bc.thinlto.bc
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
declare void @g(...)
define void @f() {
entry:
call void (...) @g()
ret void
}