[bpf] add BPF disassembler

add BPF disassembler, so tools like llvm-objdump can be used:
$ llvm-objdump -d -no-show-raw-insn ./sockex1_kern.o

./sockex1_kern.o:	file format ELF64-BPF

Disassembly of section socket1:
bpf_prog1:
       0:	r6 = r1
       8:	r0 = *(u8 *)skb[23]
      10:	*(u32 *)(r10 - 4) = r0
      18:	r1 = *(u32 *)(r6 + 4)
      20:	if r1 != 4 goto 8
      28:	r2 = r10
      30:	r2 += -4

ld_imm64 (the only 16-byte insn) and special ld_abs/ld_ind instructions
had to be treated in a special way. The decoders for the rest of the insns
are automatically generated.

Add tests to cover new functionality.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287477 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 130 insertions, 4 deletions

diff --git a/test/CodeGen/BPF/atomics.ll b/test/CodeGen/BPF/atomics.ll
index c24dd65d6eb..64c45aa4949 100644
--- a/test/CodeGen/BPF/atomics.ll
+++ b/test/CodeGen/BPF/atomics.ll
@@ -1,8 +1,8 @@
 ; RUN: llc < %s -march=bpfel -verify-machineinstrs -show-mc-encoding | FileCheck %s
 
 ; CHECK-LABEL: test_load_add_32
-; CHECK: lock *(u32 *)
-; CHECK: encoding: [0xc3
+; CHECK: lock *(u32 *)(r1 + 0) += r2
+; CHECK: encoding: [0xc3,0x21
 define void @test_load_add_32(i32* %p, i32 zeroext %v) {
 entry:
   atomicrmw add i32* %p, i32 %v seq_cst
@@ -10,8 +10,8 @@ entry:
 }
 
 ; CHECK-LABEL: test_load_add_64
-; CHECK: lock *(u64 *)
-; CHECK: encoding: [0xdb
+; CHECK: lock *(u64 *)(r1 + 0) += r2
+; CHECK: encoding: [0xdb,0x21
 define void @test_load_add_64(i64* %p, i64 zeroext %v) {
 entry:
   atomicrmw add i64* %p, i64 %v seq_cst
diff --git a/test/CodeGen/BPF/objdump_atomics.ll b/test/CodeGen/BPF/objdump_atomics.ll
new file mode 100644
index 00000000000..fb59449a147
--- /dev/null
+++ b/test/CodeGen/BPF/objdump_atomics.ll
@@ -0,0 +1,19 @@
+; RUN: llc -march=bpfel -filetype=obj -o - %s | llvm-objdump -d - | FileCheck %s
+
+; CHECK-LABEL: test_load_add_32
+; CHECK: c3 21
+; CHECK: lock *(u32 *)(r1 + 0) += r2
+define void @test_load_add_32(i32* %p, i32 zeroext %v) {
+entry:
+  atomicrmw add i32* %p, i32 %v seq_cst
+  ret void
+}
+
+; CHECK-LABEL: test_load_add_64
+; CHECK: db 21
+; CHECK: lock *(u64 *)(r1 + 0) += r2
+define void @test_load_add_64(i64* %p, i64 zeroext %v) {
+entry:
+  atomicrmw add i64* %p, i64 %v seq_cst
+  ret void
+}
diff --git a/test/CodeGen/BPF/objdump_intrinsics.ll b/test/CodeGen/BPF/objdump_intrinsics.ll
new file mode 100644
index 00000000000..ddb92b9d8fb
--- /dev/null
+++ b/test/CodeGen/BPF/objdump_intrinsics.ll
@@ -0,0 +1,88 @@
+; RUN: llc -march=bpfel -filetype=obj -o - %s | llvm-objdump -d - | FileCheck %s
+
+; Function Attrs: nounwind uwtable
+define i32 @ld_b(i64 %foo, i64* nocapture %bar, i8* %ctx, i8* %ctx2) #0 {
+  %1 = tail call i64 @llvm.bpf.load.byte(i8* %ctx, i64 123) #2
+  %2 = add i64 %1, %foo
+  %3 = load volatile i64, i64* %bar, align 8
+  %4 = add i64 %2, %3
+  %5 = tail call i64 @llvm.bpf.load.byte(i8* %ctx2, i64 %foo) #2
+  %6 = add i64 %4, %5
+  %7 = load volatile i64, i64* %bar, align 8
+  %8 = add i64 %6, %7
+  %9 = trunc i64 %8 to i32
+  ret i32 %9
+; CHECK-LABEL: ld_b:
+; CHECK: r0 = *(u8 *)skb[123]
+; CHECK: r0 = *(u8 *)skb[r
+}
+
+declare i64 @llvm.bpf.load.byte(i8*, i64) #1
+
+; Function Attrs: nounwind uwtable
+define i32 @ld_h(i8* %ctx, i8* %ctx2, i32 %foo) #0 {
+  %1 = tail call i64 @llvm.bpf.load.half(i8* %ctx, i64 123) #2
+  %2 = sext i32 %foo to i64
+  %3 = tail call i64 @llvm.bpf.load.half(i8* %ctx2, i64 %2) #2
+  %4 = add i64 %3, %1
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+; CHECK-LABEL: ld_h:
+; CHECK: r0 = *(u16 *)skb[r
+; CHECK: r0 = *(u16 *)skb[123]
+}
+
+declare i64 @llvm.bpf.load.half(i8*, i64) #1
+
+; Function Attrs: nounwind uwtable
+define i32 @ld_w(i8* %ctx, i8* %ctx2, i32 %foo) #0 {
+  %1 = tail call i64 @llvm.bpf.load.word(i8* %ctx, i64 123) #2
+  %2 = sext i32 %foo to i64
+  %3 = tail call i64 @llvm.bpf.load.word(i8* %ctx2, i64 %2) #2
+  %4 = add i64 %3, %1
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+; CHECK-LABEL: ld_w:
+; CHECK: r0 = *(u32 *)skb[r
+; CHECK: r0 = *(u32 *)skb[123]
+}
+
+declare i64 @llvm.bpf.load.word(i8*, i64) #1
+
+define i32 @ld_pseudo() #0 {
+entry:
+  %call = tail call i64 @llvm.bpf.pseudo(i64 2, i64 3)
+  tail call void @bar(i64 %call, i32 4) #2
+  ret i32 0
+; CHECK-LABEL: ld_pseudo:
+; CHECK: ld_pseudo r1, 2, 3
+}
+
+declare void @bar(i64, i32) #1
+
+declare i64 @llvm.bpf.pseudo(i64, i64) #2
+
+define i32 @bswap(i64 %a, i64 %b, i64 %c) #0 {
+entry:
+  %0 = tail call i64 @llvm.bswap.i64(i64 %a)
+  %conv = trunc i64 %b to i32
+  %1 = tail call i32 @llvm.bswap.i32(i32 %conv)
+  %conv1 = zext i32 %1 to i64
+  %add = add i64 %conv1, %0
+  %conv2 = trunc i64 %c to i16
+  %2 = tail call i16 @llvm.bswap.i16(i16 %conv2)
+  %conv3 = zext i16 %2 to i64
+  %add4 = add i64 %add, %conv3
+  %conv5 = trunc i64 %add4 to i32
+  ret i32 %conv5
+; CHECK-LABEL: bswap:
+; CHECK: bswap64 r1
+; CHECK: bswap32 r2
+; CHECK: r2 += r1
+; CHECK: bswap16 r3
+; CHECK: r2 += r3
+}
+
+declare i64 @llvm.bswap.i64(i64) #1
+declare i32 @llvm.bswap.i32(i32) #1
+declare i16 @llvm.bswap.i16(i16) #1
diff --git a/test/CodeGen/BPF/objdump_trivial.ll b/test/CodeGen/BPF/objdump_trivial.ll
new file mode 100644
index 00000000000..48fee21a2e4
--- /dev/null
+++ b/test/CodeGen/BPF/objdump_trivial.ll
@@ -0,0 +1,19 @@
+; RUN: llc -march=bpfel -filetype=obj -o - %s | llvm-objdump -d - | FileCheck %s
+
+; CHECK: if r2 s> r1 goto
+; CHECK: call
+; CHECK: exit
+
+declare void @a()
+declare void @b()
+
+define void @foo(i32 %a) {
+%b = icmp sgt i32 %a, -1
+br i1 %b, label %x, label %y
+x:
+call void @a()
+ret void
+y:
+call void @b()
+ret void
+}