Add a FunctionImporter helper to perform summary-based cross-module function importing

Summary:
This is a helper to perform cross-module import for ThinLTO. Right now
it is importing naively every possible called functions.

Reviewers: tejohnson

Subscribers: dexonsmith, llvm-commits

Differential Revision: http://reviews.llvm.org/D14914

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 253954

1 files changed, 93 insertions, 0 deletions

diff --git a/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll b/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll
new file mode 100644
index 00000000000..c0298b55ea4
--- /dev/null
+++ b/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll
@@ -0,0 +1,93 @@
+@globalvar = global i32 1, align 4
+@staticvar = internal global i32 1, align 4
+@staticconstvar = internal unnamed_addr constant [2 x i32] [i32 10, i32 20], align 4
+@commonvar = common global i32 0, align 4
+@P = internal global void ()* null, align 8
+
+@weakalias = weak alias void (...), bitcast (void ()* @globalfunc1 to void (...)*)
+@analias = alias void (...), bitcast (void ()* @globalfunc2 to void (...)*)
+@linkoncealias = alias void (...), bitcast (void ()* @linkoncefunc to void (...)*)
+
+define void @globalfunc1() #0 {
+entry:
+  ret void
+}
+
+define void @globalfunc2() #0 {
+entry:
+  ret void
+}
+
+define linkonce_odr void @linkoncefunc() #0 {
+entry:
+  ret void
+}
+
+define i32 @referencestatics(i32 %i) #0 {
+entry:
+  %i.addr = alloca i32, align 4
+  store i32 %i, i32* %i.addr, align 4
+  %call = call i32 @staticfunc()
+  %0 = load i32, i32* @staticvar, align 4
+  %add = add nsw i32 %call, %0
+  %1 = load i32, i32* %i.addr, align 4
+  %idxprom = sext i32 %1 to i64
+  %arrayidx = getelementptr inbounds [2 x i32], [2 x i32]* @staticconstvar, i64 0, i64 %idxprom
+  %2 = load i32, i32* %arrayidx, align 4
+  %add1 = add nsw i32 %add, %2
+  ret i32 %add1
+}
+
+define i32 @referenceglobals(i32 %i) #0 {
+entry:
+  %i.addr = alloca i32, align 4
+  store i32 %i, i32* %i.addr, align 4
+  call void @globalfunc1()
+  %0 = load i32, i32* @globalvar, align 4
+  ret i32 %0
+}
+
+define i32 @referencecommon(i32 %i) #0 {
+entry:
+  %i.addr = alloca i32, align 4
+  store i32 %i, i32* %i.addr, align 4
+  %0 = load i32, i32* @commonvar, align 4
+  ret i32 %0
+}
+
+define void @setfuncptr() #0 {
+entry:
+  store void ()* @staticfunc2, void ()** @P, align 8
+  ret void
+}
+
+define void @callfuncptr() #0 {
+entry:
+  %0 = load void ()*, void ()** @P, align 8
+  call void %0()
+  ret void
+}
+
+@weakvar = weak global i32 1, align 4
+define weak void @weakfunc() #0 {
+entry:
+  ret void
+}
+
+define void @callweakfunc() #0 {
+entry:
+  call void @weakfunc()
+  ret void
+}
+
+define internal i32 @staticfunc() #0 {
+entry:
+  ret i32 1
+}
+
+define internal void @staticfunc2() #0 {
+entry:
+  ret void
+}
+
+