[ThinLTO] Handle bitcode without function summary sections gracefully
Summary:
Several fixes to the handling of bitcode files without function summary
sections so that they are skipped during ThinLTO processing in llvm-lto
and the gold plugin when appropriate instead of aborting.
1 Don't assert when trying to add a FunctionInfo that doesn't have
a summary attached.
2 Skip FunctionInfo structures that don't have attached function summary
sections when trying to create the combined function summary.
3 In both llvm-lto and gold-plugin, check whether a bitcode file has
a function summary section before trying to parse the index, and skip
the bitcode file if it does not.
4 Fix hasFunctionSummaryInMemBuffer in BitcodeReader, which had a bug
where we returned to early while looking for the summary section.
Also added llvm-lto and gold-plugin based tests for cases where we
don't have function summaries in the bitcode file. I verified that
either the first couple fixes described above are enough to avoid the
crashes, or fixes 1,3,4. But have combined them all here for added
robustness.
Reviewers: joker.eph
Subscribers: llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D14903
llvm-svn: 253796
diff --git a/llvm/test/Linker/funcimport.ll b/llvm/test/Linker/funcimport.ll
index dad9b95..d6aa050 100644
--- a/llvm/test/Linker/funcimport.ll
+++ b/llvm/test/Linker/funcimport.ll
@@ -1,3 +1,10 @@
+; First ensure that the ThinLTO handling in llvm-link and llvm-lto handles
+; bitcode without function summary sections gracefully.
+; RUN: llvm-as %s -o %t.bc
+; RUN: llvm-as %p/Inputs/funcimport.ll -o %t2.bc
+; RUN: llvm-link %t.bc -functionindex=%t.bc -S
+; RUN: llvm-lto -thinlto -o %t3 %t.bc %t2.bc
+
; Do setup work for all below tests: generate bitcode and combined index
; RUN: llvm-as -function-summary %s -o %t.bc
; RUN: llvm-as -function-summary %p/Inputs/funcimport.ll -o %t2.bc