CodeGen: Introduce splitCodeGen and teach LTOCodeGenerator to use it.

llvm::splitCodeGen is a function that implements the core of parallel LTO
code generation. It uses llvm::SplitModule to split the module into linkable
partitions and spawning one code generation thread per partition. The function
produces multiple object files which can be linked in the usual way.

This has been threaded through to LTOCodeGenerator (and llvm-lto for testing
purposes). Separate patches will add parallel LTO support to the gold plugin
and lld.

Differential Revision: http://reviews.llvm.org/D12260

llvm-svn: 246236

1 files changed, 22 insertions, 0 deletions

diff --git a/llvm/test/LTO/X86/parallel.ll b/llvm/test/LTO/X86/parallel.ll
new file mode 100644
index 00000000000..15e89ea59a5
--- /dev/null
+++ b/llvm/test/LTO/X86/parallel.ll
@@ -0,0 +1,22 @@
+; RUN: llvm-as -o %t.bc %s
+; RUN: llvm-lto -exported-symbol=foo -exported-symbol=bar -j2 -o %t.o %t.bc
+; RUN: llvm-nm %t.o.0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-nm %t.o.1 | FileCheck --check-prefix=CHECK1 %s
+
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK0-NOT: bar
+; CHECK0: T foo
+; CHECK0-NOT: bar
+define void @foo() {
+  call void @bar()
+  ret void
+}
+
+; CHECK1-NOT: foo
+; CHECK1: T bar
+; CHECK1-NOT: foo
+define void @bar() {
+  call void @foo()
+  ret void
+}