[BPF] Add some selftests

Yonghong Song · Yonghong Song · commit cc70bda3c145 · 2025-08-20T11:07:17.000-07:00
diff --git a/llvm/test/CodeGen/BPF/jump_table_blockaddr.ll b/llvm/test/CodeGen/BPF/jump_table_blockaddr.ll
@@ -0,0 +1,64 @@
+; RUN: llc -march=bpf -mcpu=v4 < %s | FileCheck %s
+;
+; Source code:
+;    int bar(int a) {
+;       __label__ l1, l2;
+;       void * volatile tgt;
+;       int ret = 0;
+;       if (a)
+;         tgt = &&l1; // synthetic jump table generated here
+;       else
+;         tgt = &&l2; // another synthetic jump table
+;       goto *tgt;
+;   l1: ret += 1;
+;   l2: ret += 2;
+;       return ret;
+;     }
+;
+; Compilation Flags:
+;   clang --target=bpf -mcpu=v4 -O2 -emit-llvm -S test.c
+
+define dso_local range(i32 2, 4) i32 @bar(i32 noundef %a) local_unnamed_addr{
+entry:
+  %tgt = alloca ptr, align 8
+  %tobool.not = icmp eq i32 %a, 0
+  %. = select i1 %tobool.not, ptr blockaddress(@bar, %l2), ptr blockaddress(@bar, %l1)
+  store volatile ptr %., ptr %tgt, align 8
+  %tgt.0.tgt.0.tgt.0.tgt.0. = load volatile ptr, ptr %tgt, align 8
+  indirectbr ptr %tgt.0.tgt.0.tgt.0.tgt.0., [label %l1, label %l2]
+
+l1:                                               ; preds = %entry
+  br label %l2
+
+l2:                                               ; preds = %l1, %entry
+  %ret.0 = phi i32 [ 3, %l1 ], [ 2, %entry ]
+  ret i32 %ret.0
+}
+
+; CHECK:            r2 = BPF.JT.0.0 ll
+; CHECK-NEXT:       r2 = *(u64 *)(r2 + 0)
+; CHECK-NEXT:       r3 = BPF.JT.0.1 ll
+; CHECK-NEXT:       r3 = *(u64 *)(r3 + 0)
+; CHECK-NEXT:       if w1 == 0 goto LBB0_2
+; CHECK:            r3 = r2
+; CHECK-NEXT:  LBB0_2:                                 # %entry
+; CHECK-NEXT:       *(u64 *)(r10 - 8) = r3
+; CHECK-NEXT:       r1 = *(u64 *)(r10 - 8)
+; CHECK-NEXT:       gotox r1
+; CHECK-NEXT:  .Ltmp0:                                 # Block address taken
+; CHECK-NEXT:  LBB0_3:                                 # %l1
+; CHECK-NEXT:       w0 = 3
+; CHECK-NEXT:       goto LBB0_5
+; CHECK-NEXT:  .Ltmp1:                                 # Block address taken
+; CHECK-NEXT:  LBB0_4:                                 # %l2
+; CHECK-NEXT:       w0 = 2
+; CHECK-NEXT:  LBB0_5:                                 # %.split
+; CHECK-NEXT:       exit
+;
+; CHECK:            .section        .jumptables,"",@progbits
+; CHECK-NEXT:  BPF.JT.0.0:
+; CHECK-NEXT:       .quad   LBB0_3
+; CHECK-NEXT:       .size   BPF.JT.0.0, 8
+; CHECK-NEXT:  BPF.JT.0.1:
+; CHECK-NEXT:       .quad   LBB0_4
+; CHECK-NEXT:       .size   BPF.JT.0.1, 8
diff --git a/llvm/test/CodeGen/BPF/jump_table_global_var.ll b/llvm/test/CodeGen/BPF/jump_table_global_var.ll
@@ -0,0 +1,56 @@
+; RUN: llc -march=bpf -mcpu=v4 < %s | FileCheck %s
+;
+; Source code:
+;   int foo(unsigned a) {
+;     __label__ l1, l2;
+;     void *jt1[] = {[0]=&&l1, [1]=&&l2};
+;     int ret = 0;
+;
+;     goto *jt1[a % 2];
+;     l1: ret += 1;
+;     l2: ret += 3;
+;     return ret;
+;   }
+;
+; Compilation Flags:
+;   clang --target=bpf -mcpu=v4 -O2 -emit-llvm -S test.c
+
+@__const.foo.jt1 = private unnamed_addr constant [2 x ptr] [ptr blockaddress(@foo, %l1), ptr blockaddress(@foo, %l2)], align 8
+
+define dso_local range(i32 3, 5) i32 @foo(i32 noundef %a) local_unnamed_addr {
+entry:
+  %rem = and i32 %a, 1
+  %idxprom = zext nneg i32 %rem to i64
+  %arrayidx = getelementptr inbounds nuw [2 x ptr], ptr @__const.foo.jt1, i64 0, i64 %idxprom
+  %0 = load ptr, ptr %arrayidx, align 8
+  indirectbr ptr %0, [label %l1, label %l2]
+
+l1:                                               ; preds = %entry
+  br label %l2
+
+l2:                                               ; preds = %l1, %entry
+  %ret.0 = phi i32 [ 4, %l1 ], [ 3, %entry ]
+  ret i32 %ret.0
+}
+
+; CHECK:            w1 &= 1
+; CHECK-NEXT:       r1 <<= 3
+; CHECK-NEXT:       r2 = BPF.JT.0.0 ll
+; CHECK-NEXT:       r2 += r1
+; CHECK-NEXT:       r1 = *(u64 *)(r2 + 0)
+; CHECK-NEXT:       gotox r1
+; CHECK-NEXT:  .Ltmp0:                              # Block address taken
+; CHECK-NEXT:  LBB0_1:                              # %l1
+; CHECK-NEXT:       w0 = 4
+; CHECK-NEXT:       goto LBB0_3
+; CHECK-NEXT:  .Ltmp1:                              # Block address taken
+; CHECK-NEXT:  LBB0_2:                              # %l2
+; CHECK-NEXT:       w0 = 3
+; CHECK-NEXT:  LBB0_3:                              # %.split
+; CHECK-NEXT:       exit
+;
+; CHECK:            .section        .jumptables,"",@progbits
+; CHECK-NEXT:  BPF.JT.0.0:
+; CHECK-NEXT:       .quad   LBB0_1
+; CHECK-NEXT:       .quad   LBB0_2
+; CHECK-NEXT:       .size   BPF.JT.0.0, 16
diff --git a/llvm/test/CodeGen/BPF/jump_table_swith_stmt.ll b/llvm/test/CodeGen/BPF/jump_table_swith_stmt.ll
@@ -0,0 +1,98 @@
+; RUN: llc -march=bpf -mcpu=v4 -bpf-min-jump-table-entries=3 < %s | FileCheck %s
+;
+; Source code:
+;   int ret_user;
+;   int foo(int a)
+;   {
+;      switch (a) {
+;      case 1: ret_user = 18; break;
+;      case 20: ret_user = 6; break;
+;      case 30: ret_user = 2; break;
+;      default: break;
+;      }
+;      return 0;
+;   }
+;
+; Compilation Flags:
+;   clang --target=bpf -mcpu=v4 -O2 -emit-llvm -S test.c
+
+@ret_user = dso_local local_unnamed_addr global i32 0, align 4
+
+define dso_local noundef i32 @foo(i32 noundef %a) local_unnamed_addr {
+entry:
+  switch i32 %a, label %sw.epilog [
+    i32 1, label %sw.epilog.sink.split
+    i32 20, label %sw.bb1
+    i32 30, label %sw.bb2
+  ]
+
+sw.bb1:                                           ; preds = %entry
+  br label %sw.epilog.sink.split
+
+sw.bb2:                                           ; preds = %entry
+  br label %sw.epilog.sink.split
+
+sw.epilog.sink.split:                             ; preds = %entry, %sw.bb1, %sw.bb2
+  %.sink = phi i32 [ 2, %sw.bb2 ], [ 6, %sw.bb1 ], [ 18, %entry ]
+  store i32 %.sink, ptr @ret_user, align 4
+  br label %sw.epilog
+
+sw.epilog:                                        ; preds = %sw.epilog.sink.split, %entry
+  ret i32 0
+}
+
+; CHECK:            w1 += -1
+; CHECK-NEXT:       if w1 > 29 goto LBB0_5
+; CHECK:            w2 = 18
+; CHECK-NEXT:       r1 <<= 3
+; CHECK-NEXT:       r3 = BPF.JT.0.0 ll
+; CHECK-NEXT:       r4 = BPF.JT.0.0 ll
+; CHECK-NEXT:       r4 += r1
+; CHECK-NEXT:       r1 = *(u64 *)(r4 + 0)
+; CHECK-NEXT:       r3 += r1
+; CHECK-NEXT:       gotox r3
+; CHECK-NEXT:  LBB0_2:                                 # %sw.bb1
+; CHECK-NEXT:       w2 = 6
+; CHECK-NEXT:       goto LBB0_4
+; CHECK-NEXT:  LBB0_3:                                 # %sw.bb2
+; CHECK-NEXT:       w2 = 2
+; CHECK-NEXT:  LBB0_4:                                 # %sw.epilog.sink.split
+; CHECK-NEXT:       r1 = ret_user ll
+; CHECK-NEXT:       *(u32 *)(r1 + 0) = w2
+; CHECK-NEXT:  LBB0_5:                                 # %sw.epilog
+; CHECK-NEXT:       w0 = 0
+; CHECK-NEXT:       exit
+
+; CHECK:            .section        .jumptables,"",@progbits
+; CHECK-NEXT:  BPF.JT.0.0:
+; CHECK-NEXT:       .quad   LBB0_4
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_2
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_5
+; CHECK-NEXT:       .quad   LBB0_3
+; CHECK-NEXT:       .size   BPF.JT.0.0, 240
