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author | Yonghong Song <yhs@fb.com> | 2017-12-03 19:02:03 +0000 |
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committer | Yonghong Song <yhs@fb.com> | 2017-12-03 19:02:03 +0000 |
commit | 170dfab48d7741847180760e8ac42308e08ee2db (patch) | |
tree | 65fb7bd6e8e8de24b0a48725ee743c1c30470fc4 | |
parent | 1254c70db9559d0c7cbcfa98d046120bd15f2a29 (diff) | |
download | llvm-170dfab48d7741847180760e8ac42308e08ee2db.zip llvm-170dfab48d7741847180760e8ac42308e08ee2db.tar.gz llvm-170dfab48d7741847180760e8ac42308e08ee2db.tar.bz2 |
bpf: fix bug on silently truncating 64-bit immediate
We came across an llvm bug when compiling some testcases that 64-bit
immediates are silently truncated into 32-bit and then packed into
BPF_JMP | BPF_K encoding. This caused comparison with wrong value.
This bug looks to be introduced by r308080 (llvm 5.0). The Select_Ri pattern is
supposed to be lowered into J*_Ri while the latter only support 32-bit
immediate encoding, therefore Select_Ri should have similar immediate
predicate check as what J*_Ri are doing.
The bug is fixed by
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315889 91177308-0d34-0410-b5e6-96231b3b80d8
in llvm 6.0.
This patch is largely the same as the fix in llvm 6.0 except
one minor adjustment for the test case.
Reported-by: John Fastabend <john.fastabend@gmail.com>
Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Yonghong Song <yhs@fb.com>
llvm-svn: 319633
-rw-r--r-- | llvm/lib/Target/BPF/BPFISelLowering.cpp | 8 | ||||
-rw-r--r-- | llvm/lib/Target/BPF/BPFInstrInfo.td | 2 | ||||
-rw-r--r-- | llvm/test/CodeGen/BPF/select_ri.ll | 35 |
3 files changed, 42 insertions, 3 deletions
diff --git a/llvm/lib/Target/BPF/BPFISelLowering.cpp b/llvm/lib/Target/BPF/BPFISelLowering.cpp index 81b0aa7..5740b49 100644 --- a/llvm/lib/Target/BPF/BPFISelLowering.cpp +++ b/llvm/lib/Target/BPF/BPFISelLowering.cpp @@ -578,11 +578,15 @@ BPFTargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI, .addReg(LHS) .addReg(MI.getOperand(2).getReg()) .addMBB(Copy1MBB); - else + else { + int64_t imm32 = MI.getOperand(2).getImm(); + // sanity check before we build J*_ri instruction. + assert (isInt<32>(imm32)); BuildMI(BB, DL, TII.get(NewCC)) .addReg(LHS) - .addImm(MI.getOperand(2).getImm()) + .addImm(imm32) .addMBB(Copy1MBB); + } // Copy0MBB: // %FalseValue = ... diff --git a/llvm/lib/Target/BPF/BPFInstrInfo.td b/llvm/lib/Target/BPF/BPFInstrInfo.td index f683578..59e92f8 100644 --- a/llvm/lib/Target/BPF/BPFInstrInfo.td +++ b/llvm/lib/Target/BPF/BPFInstrInfo.td @@ -464,7 +464,7 @@ let usesCustomInserter = 1 in { (ins GPR:$lhs, i64imm:$rhs, i64imm:$imm, GPR:$src, GPR:$src2), "# Select PSEUDO $dst = $lhs $imm $rhs ? $src : $src2", [(set i64:$dst, - (BPFselectcc i64:$lhs, (i64 imm:$rhs), (i64 imm:$imm), i64:$src, i64:$src2))]>; + (BPFselectcc i64:$lhs, (i64 i64immSExt32:$rhs), (i64 imm:$imm), i64:$src, i64:$src2))]>; } // load 64-bit global addr into register diff --git a/llvm/test/CodeGen/BPF/select_ri.ll b/llvm/test/CodeGen/BPF/select_ri.ll index c4ac376..3610d40 100644 --- a/llvm/test/CodeGen/BPF/select_ri.ll +++ b/llvm/test/CodeGen/BPF/select_ri.ll @@ -25,3 +25,38 @@ entry: } attributes #0 = { norecurse nounwind readonly } + +; test immediate out of 32-bit range +; Source file: + +; unsigned long long +; load_word(void *buf, unsigned long long off) +; asm("llvm.bpf.load.word"); +; +; int +; foo(void *buf) +; { +; unsigned long long sum = 0; +; +; sum += load_word(buf, 100); +; sum += load_word(buf, 104); +; +; if (sum != 0x1ffffffffULL) +; return ~0U; +; +; return 0; +;} + +; Function Attrs: nounwind readonly +define i32 @foo(i8*) local_unnamed_addr #0 { + %2 = tail call i64 @llvm.bpf.load.word(i8* %0, i64 100) + %3 = tail call i64 @llvm.bpf.load.word(i8* %0, i64 104) + %4 = add i64 %3, %2 + %5 = icmp ne i64 %4, 8589934591 +; CHECK: r{{[0-9]+}} = 8589934591ll + %6 = sext i1 %5 to i32 + ret i32 %6 +} + +; Function Attrs: nounwind readonly +declare i64 @llvm.bpf.load.word(i8*, i64) #1 |