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author | Björn Gustavsson <bjorn@erlang.org> | 2011-12-05 09:22:12 +0100 |
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committer | Björn Gustavsson <bjorn@erlang.org> | 2011-12-06 13:22:18 +0100 |
commit | 1687a490039698fab6ccabdbbd61faa5d9d5eb41 (patch) | |
tree | 3f84ca91da1791e39fa42d944bd627f866c34ba9 | |
parent | 43a493df03174bc04d9a62edb4cff96943eebe35 (diff) | |
download | otp-1687a490039698fab6ccabdbbd61faa5d9d5eb41.tar.gz otp-1687a490039698fab6ccabdbbd61faa5d9d5eb41.tar.bz2 otp-1687a490039698fab6ccabdbbd61faa5d9d5eb41.zip |
beam_validator: Fix type for failure label for bs_start_match2/5
A bs_start_match2/5 instruction will never fail (take the branch) if
given a match state or a binary. Therefore, the type at the failure
label should be 'term', not match state or binary. Without this
correction, the beam_validator will reject safe programs.
-rw-r--r-- | lib/compiler/src/beam_validator.erl | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl index fe3b1680d9..95f12df40d 100644 --- a/lib/compiler/src/beam_validator.erl +++ b/lib/compiler/src/beam_validator.erl @@ -670,10 +670,20 @@ valfun_4({get_tuple_element,Src,I,Dst}, Vst) -> valfun_4({test,bs_start_match2,{f,Fail},Live,[Ctx,NeedSlots],Ctx}, Vst0) -> %% If source and destination registers are the same, match state %% is OK as input. - _ = get_move_term_type(Ctx, Vst0), + CtxType = get_move_term_type(Ctx, Vst0), verify_live(Live, Vst0), Vst1 = prune_x_regs(Live, Vst0), - Vst = branch_state(Fail, Vst1), + BranchVst = case CtxType of + {match_context,_,_} -> + %% The failure branch will never be taken when Ctx + %% is a match context. Therefore, the type for Ctx + %% at the failure label must not be match_context + %% (or we could reject legal code). + set_type_reg(term, Ctx, Vst1); + _ -> + Vst1 + end, + Vst = branch_state(Fail, BranchVst), set_type_reg(bsm_match_state(NeedSlots), Ctx, Vst); valfun_4({test,bs_start_match2,{f,Fail},Live,[Src,Slots],Dst}, Vst0) -> assert_term(Src, Vst0), |