[lld] [llvm] [DTLTO] support distributing bitcode from FatLTO objects (PR #176928)

[Teresa Johnson via llvm-commits]

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@@ -0,0 +1,55 @@
+REQUIRES: ld.lld,llvm-ar
+
+# Test that a DTLTO link succeeds and outputs the expected set of files
+# correctly when FatLTO objects are present.
+RUN: rm -rf %t && split-file %s %t && cd %t
+
+# Compile bitcode. -O2 is required for cross-module importing.
+RUN: %clang -O2 --target=x86_64-linux-gnu -flto=thin -ffat-lto-objects -c \
+RUN:   foo.c boo.c start.c
+
+# We want to test FatLTO objects when included in archives.
+RUN: llvm-ar rcs foo.a foo.o
+RUN: llvm-ar rcsT boo.a boo.o
+
+# Build with DTLTO.
+RUN: %clang --target=x86_64-linux-gnu -flto=thin -ffat-lto-objects \
+RUN:   -fuse-ld=lld -nostdlib foo.a boo.a start.o -Wl,--save-temps \
+RUN:   -fthinlto-distributor=%python \
+RUN:   -Xthinlto-distributor=%llvm_src_root/utils/dtlto/local.py
+
+# Check that the required output files have been created.
+RUN: ls | FileCheck %s
+
+# thin archive member: <archive>(<member> at <offset>).<task>.<pid>.<task>.<pid>.native.o
+CHECK-DAG: {{^}}boo.a(boo.o at [[#BOO_OFFSET:]]).3.[[#%X,HEXPID:]].3.[[#PID:]].native.o{{$}}
+# archive member: <archive>(<member> at <offset>).<task>.<pid>.<task>.<pid>.native.o
+CHECK-DAG: {{^}}foo.a(foo.o at [[#FOO_OFFSET:]]).2.[[#%X,HEXPID]].2.[[#PID]].native.o{{$}}
+# FatLTO object: <file>.<task>.<pid>.<task>.<pid>.native.o.
+CHECK-DAG: {{^}}start.o.1.[[#%X,HEXPID]].1.[[#PID]].native.o{{$}}
+
+# It is important that cross-module inlining occurs for this test to show that
+# Clang can successfully load the bitcode file dependencies recorded in the
+# summary indices. Explicitly check that the expected importing has occurred.
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teresajohnson wrote:

That is fine, I would just update the comment.

https://github.com/llvm/llvm-project/pull/176928