bpf: add inline-asm support

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
llvm-svn: 313593
diff --git a/llvm/test/CodeGen/BPF/inline_asm.ll b/llvm/test/CodeGen/BPF/inline_asm.ll
new file mode 100644
index 0000000..7822ac4
--- /dev/null
+++ b/llvm/test/CodeGen/BPF/inline_asm.ll
@@ -0,0 +1,54 @@
+; RUN: llc < %s -march=bpfel -verify-machineinstrs | FileCheck %s
+; RUN: llc < %s -march=bpfeb -verify-machineinstrs | FileCheck %s
+
+; Source code:
+; int g[2];
+;
+; int test(void *ctx) {
+;   int a = 4, b;
+;   unsigned long long c = 333333333333ULL;
+;   asm volatile("r0 = *(u16 *)skb[%0]" : : "i"(2));
+;   asm volatile("r0 = *(u16 *)skb[%0]" : : "r"(a));
+;   asm volatile("%0 = %1" : "=r"(b) : "i"(4));
+;   asm volatile("%0 = %1 ll" : "=r"(b) : "i"(c));
+;   asm volatile("%0 = *(u16 *) %1" : "=r"(b) : "m"(a));
+;   asm volatile("%0 = *(u32 *) %1" : "=r"(b) : "m"(g[1]));
+;   return b;
+; }
+;
+
+@g = common global [2 x i32] zeroinitializer, align 4
+
+; Function Attrs: nounwind
+define i32 @test(i8* nocapture readnone %ctx) local_unnamed_addr #0 {
+entry:
+  %a = alloca i32, align 4
+  %0 = bitcast i32* %a to i8*
+  call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %0) #2
+  store i32 4, i32* %a, align 4
+  tail call void asm sideeffect "r0 = *(u16 *)skb[$0]", "i"(i32 2) #2
+; CHECK: r0 = *(u16 *)skb[2]
+  tail call void asm sideeffect "r0 = *(u16 *)skb[$0]", "r"(i32 4) #2
+; CHECK: r0 = *(u16 *)skb[r1]
+  %1 = tail call i32 asm sideeffect "$0 = $1", "=r,i"(i32 4) #2
+; CHECK: r1 = 4
+  %2 = tail call i32 asm sideeffect "$0 = $1 ll", "=r,i"(i64 333333333333) #2
+; CHECK: r1 = 333333333333 ll
+  %3 = call i32 asm sideeffect "$0 = *(u16 *) $1", "=r,*m"(i32* nonnull %a) #2
+; CHECK: r1 = *(u16 *) (r10 - 4)
+  %4 = call i32 asm sideeffect "$0 = *(u32 *) $1", "=r,*m"(i32* getelementptr inbounds ([2 x i32], [2 x i32]* @g, i64 0, i64 1)) #2
+; CHECK: r1 = g ll
+; CHECK: r0 = *(u32 *) (r1 + 4)
+  call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %0) #2
+  ret i32 %4
+}
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #1
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #1
+
+attributes #0 = { nounwind }
+attributes #1 = { argmemonly nounwind }
+attributes #2 = { nounwind }