File 2113-compiler-Fix-awkward-match-context-substitution.patch of Package erlang
From 6ae9975689858d0e0c9af0a36869c012bb3762c0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20H=C3=B6gberg?= <john@erlang.org>
Date: Wed, 7 Aug 2019 14:00:09 +0200
Subject: [PATCH 2/2] compiler: Fix awkward match context substitution
This worked out by accident since codegen never actually looks at
the arguments for 'succeeded'; it just assumes that they reference
the preceding instruction.
---
lib/compiler/src/beam_ssa_lint.erl | 20 +++++++++++++++++++-
lib/compiler/src/beam_ssa_pre_codegen.erl | 4 ++++
lib/compiler/test/misc_SUITE.erl | 24 ++++++++++++++++++++++--
3 files changed, 45 insertions(+), 3 deletions(-)
diff --git a/lib/compiler/src/beam_ssa_lint.erl b/lib/compiler/src/beam_ssa_lint.erl
index b2a8c1a0d1..224095d4c4 100644
--- a/lib/compiler/src/beam_ssa_lint.erl
+++ b/lib/compiler/src/beam_ssa_lint.erl
@@ -65,7 +65,13 @@ format_error({{_M,F,A},{phi_inside_block, Name, Id}}) ->
[F, A, format_var(Name), Id]);
format_error({{_M,F,A},{undefined_label_in_phi, Label, I}}) ->
io_lib:format("~p/~p: Unknown block label ~p in phi node ~ts",
- [F, A, Label, format_instr(I)]).
+ [F, A, Label, format_instr(I)]);
+format_error({{_M,F,A},{succeeded_not_preceded, I}}) ->
+ io_lib:format("~p/~p: ~ts does not reference the preceding instruction",
+ [F, A, format_instr(I)]);
+format_error({{_M,F,A},{succeeded_not_last, I}}) ->
+ io_lib:format("~p/~p: ~ts is not the last instruction in its block",
+ [F, A, format_instr(I)]).
format_instr(I) ->
[$',beam_ssa_pp:format_instr(I),$'].
@@ -229,6 +235,18 @@ vvars_block(Id, State0) ->
State :: #vvars{}.
vvars_block_1([], State) ->
State;
+vvars_block_1([#b_set{dst=OpVar,args=OpArgs}=I,
+ #b_set{op=succeeded,args=[OpVar],dst=SuccVar}], State) ->
+ ok = vvars_assert_args(OpArgs, I, State),
+ vvars_save_var(SuccVar, vvars_save_var(OpVar, State));
+vvars_block_1([#b_set{op=succeeded,args=Args}=I | [_|_]], State) ->
+ ok = vvars_assert_args(Args, I, State),
+ %% 'succeeded' must be the last instruction in its block.
+ throw({succeeded_not_last, I});
+vvars_block_1([#b_set{op=succeeded,args=Args}=I], State)->
+ ok = vvars_assert_args(Args, I, State),
+ %% 'succeeded' must be be directly preceded by the operation it checks.
+ throw({succeeded_not_preceded, I});
vvars_block_1([#b_set{ dst = Dst, op = phi } | Is], State) ->
%% We don't check phi node arguments at this point since we may not have
%% visited their definition yet. They'll be handled later on in
diff --git a/lib/compiler/src/beam_ssa_pre_codegen.erl b/lib/compiler/src/beam_ssa_pre_codegen.erl
index 9847b87b18..61b2155e39 100644
--- a/lib/compiler/src/beam_ssa_pre_codegen.erl
+++ b/lib/compiler/src/beam_ssa_pre_codegen.erl
@@ -603,6 +603,10 @@ bs_instrs([{L,#b_blk{is=Is0}=Blk}|Bs], CtxChain, Acc0) ->
bs_instrs([], _, Acc) ->
reverse(Acc).
+bs_instrs_is([#b_set{op=succeeded}=I|Is], CtxChain, Acc) ->
+ %% This instruction refers to a specific operation, so we must not
+ %% substitute the context argument.
+ bs_instrs_is(Is, CtxChain, [I | Acc]);
bs_instrs_is([#b_set{op=Op,args=Args0}=I0|Is], CtxChain, Acc) ->
Args = [bs_subst_ctx(A, CtxChain) || A <- Args0],
I1 = I0#b_set{args=Args},
diff --git a/lib/compiler/test/misc_SUITE.erl b/lib/compiler/test/misc_SUITE.erl
index eb60dc049d..20fadc4fdb 100644
--- a/lib/compiler/test/misc_SUITE.erl
+++ b/lib/compiler/test/misc_SUITE.erl
@@ -274,13 +274,33 @@ silly_coverage(Config) when is_list(Config) ->
bad_ssa_lint_input() ->
{b_module,#{},t,
- [{foobar,1},{module_info,0},{module_info,1}],
+ [{a,1},{b,1},{c,1},{module_info,0},{module_info,1}],
[],
[{b_function,
- #{func_info => {t,foobar,1},location => {"t.erl",4}},
+ #{func_info => {t,a,1},location => {"t.erl",4}},
[{b_var,0}],
#{0 => {b_blk,#{},[],{b_ret,#{},{b_var,'@undefined_var'}}}},
3},
+ {b_function,
+ #{func_info => {t,b,1},location => {"t.erl",5}},
+ [{b_var,0}],
+ #{0 =>
+ {b_blk,#{},
+ [{b_set,#{},{b_var,'@first_var'},first_op,[]},
+ {b_set,#{},{b_var,'@second_var'},second_op,[]},
+ {b_set,#{},{b_var,'@ret'},succeeded,[{b_var,'@first_var'}]}],
+ {b_ret,#{},{b_var,'@ret'}}}},
+ 3},
+ {b_function,
+ #{func_info => {t,c,1},location => {"t.erl",6}},
+ [{b_var,0}],
+ #{0 =>
+ {b_blk,#{},
+ [{b_set,#{},{b_var,'@first_var'},first_op,[]},
+ {b_set,#{},{b_var,'@ret'},succeeded,[{b_var,'@first_var'}]},
+ {b_set,#{},{b_var,'@second_var'},second_op,[]}],
+ {b_ret,#{},{b_var,'@ret'}}}},
+ 3},
{b_function,
#{func_info => {t,module_info,0}},
[],
--
2.16.4
