llvm/test/Bitcode/thinlto-empty-summary-section.ll

; Ensure we get a summary block even when the file is empty.
; RUN: opt -module-summary %s -o %t.o
; RUN: llvm-bcanalyzer -dump %t.o | FileCheck %s

; CHECK: <GLOBALVAL_SUMMARY_BLOCK
; CHECK: <VERSION op0=
; CHECK: </GLOBALVAL_SUMMARY_BLOCK>
[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 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282037 91177308-0d34-0410-b5e6-96231b3b80d8 2016-09-20 23:07:17 +00:00			`; Ensure we get a summary block even when the file is empty.`
			`; RUN: opt -module-summary %s -o %t.o`
			`; RUN: llvm-bcanalyzer -dump %t.o \| FileCheck %s`

			`; CHECK: <GLOBALVAL_SUMMARY_BLOCK`
			`; CHECK: <VERSION op0=`
			`; CHECK: </GLOBALVAL_SUMMARY_BLOCK>`