Add to the split module utility an SCC based method which allows not to globalize any local variables.

    
    Summary:
    Currently llvm::SplitModule as the first step globalizes all local objects, which might not be desirable in some scenarios.
    This change adds a new flag to llvm::SplitModule that uses SCC approach to search for a balanced partition without the need to externalize symbols.
    Such partition might not be possible or fully balanced for a given number of partitions, and is a function of the module properties (global/local dependencies within the module).
    
    Joint development Tobias Edler von Koch (tobias@codeaurora.org) and Sergei Larin (slarin@codeaurora.org)
    
    Subscribers: llvm-commits, joker.eph
    
    Differential Revision: http://reviews.llvm.org/D16124

llvm-svn: 258083

1 files changed, 65 insertions, 0 deletions

diff --git a/llvm/test/tools/llvm-split/preserve-locals.ll b/llvm/test/tools/llvm-split/preserve-locals.ll
new file mode 100644
index 00000000000..7556c25bba3
--- /dev/null
+++ b/llvm/test/tools/llvm-split/preserve-locals.ll
@@ -0,0 +1,65 @@
+; RUN: llvm-split -preserve-locals -o %t %s
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+
+; The local_var and local_func must not be separated.
+; CHECK0: @local_var
+; CHECK0: define internal fastcc void @local_func
+; The main and a must not be separated.
+; The main and local_func must not be together.
+; CHECK1: @a
+; CHECK1: define i32 @main
+; CHECK1: declare fastcc void @local_func
+
+@a = internal global i32 0, align 4
+@global_storage = common global i32 0, align 4
+@local_var = internal global i32 0, align 4
+
+; Function Attrs: nounwind
+define i32 @main(i32 %x) {
+entry:
+  %call = call fastcc i32 @foo(i32 %x, i32* nonnull @a)
+  %call1 = call fastcc i32 @baz(i32 %x)
+  %add = add nsw i32 %call, %call1
+  ret i32 %add
+}
+
+; Function Attrs: nounwind
+define fastcc i32 @bar(i32 %b) {
+entry:
+  %call = call fastcc i32 @baz(i32 %b)
+  ret i32 %call
+}
+
+; Function Attrs: nounwind
+define fastcc i32 @baz(i32 %x) {
+entry:
+  store i32 %x, i32* @global_storage, align 4
+  %shl = shl i32 %x, %x
+  ret i32 %shl
+}
+
+; Function Attrs: noinline nounwind
+define fastcc i32 @foo(i32 %a, i32* nocapture %b) {
+entry:
+  call fastcc void @local_func()
+  %call = call fastcc i32 @bar(i32 %a)
+  %0 = load i32, i32* @global_storage, align 4
+  %call1 = call fastcc i32 @baz(i32 %0)
+  %add = add nsw i32 %call, %call1
+  store i32 %add, i32* %b, align 4
+  %call.i = call fastcc i32 @baz(i32 %add) #2
+  %add.i = add nsw i32 %call.i, 2
+  %1 = load volatile i32, i32* @local_var, align 4
+  %add3 = add nsw i32 %add.i, %1
+  ret i32 %add3
+}
+
+; Function Attrs: noinline nounwind
+define internal fastcc void @local_func() section ".text" {
+entry:
+  %0 = load i32, i32* @global_storage, align 4
+  %call = call fastcc i32 @foo(i32 %0, i32* null)
+  store volatile i32 %call, i32* @local_var, align 4
+  ret void
+}