78 lines
2.7 KiB
Diff
78 lines
2.7 KiB
Diff
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From 997f11f54322883c3181225f29d101a597f31730 Mon Sep 17 00:00:00 2001
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From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
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Date: Wed, 24 Aug 2022 17:36:47 -0300
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Subject: [PATCH] Bug: 'break' may not properly close variable in a 'for' loop
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Function 'leaveblock' was generating "break" label before removing
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variables from the closing block. If 'createlabel' created a 'close'
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instruction (which it did when matching a goto/break that exited
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the scope of an upvalue), that instruction would use the wrong level.
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---
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lparser.c | 16 ++++++++--------
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testes/locals.lua | 20 ++++++++++++++++++++
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2 files changed, 28 insertions(+), 8 deletions(-)
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diff --git a/lparser.c b/lparser.c
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index a5cd55257..fe693b571 100644
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--- a/src/lparser.c
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+++ b/src/lparser.c
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@@ -674,19 +674,19 @@ static void leaveblock (FuncState *fs) {
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LexState *ls = fs->ls;
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int hasclose = 0;
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int stklevel = reglevel(fs, bl->nactvar); /* level outside the block */
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- if (bl->isloop) /* fix pending breaks? */
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+ removevars(fs, bl->nactvar); /* remove block locals */
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+ lua_assert(bl->nactvar == fs->nactvar); /* back to level on entry */
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+ if (bl->isloop) /* has to fix pending breaks? */
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hasclose = createlabel(ls, luaS_newliteral(ls->L, "break"), 0, 0);
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- if (!hasclose && bl->previous && bl->upval)
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+ if (!hasclose && bl->previous && bl->upval) /* still need a 'close'? */
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luaK_codeABC(fs, OP_CLOSE, stklevel, 0, 0);
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- fs->bl = bl->previous;
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- removevars(fs, bl->nactvar);
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- lua_assert(bl->nactvar == fs->nactvar);
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fs->freereg = stklevel; /* free registers */
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ls->dyd->label.n = bl->firstlabel; /* remove local labels */
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- if (bl->previous) /* inner block? */
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- movegotosout(fs, bl); /* update pending gotos to outer block */
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+ fs->bl = bl->previous; /* current block now is previous one */
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+ if (bl->previous) /* was it a nested block? */
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+ movegotosout(fs, bl); /* update pending gotos to enclosing block */
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else {
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- if (bl->firstgoto < ls->dyd->gt.n) /* pending gotos in outer block? */
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+ if (bl->firstgoto < ls->dyd->gt.n) /* still pending gotos? */
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undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]); /* error */
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}
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}
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diff --git a/testes/locals.lua b/testes/locals.lua
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index ddb75054f..d50beaa52 100644
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--- a/testes/locals.lua
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+++ b/testes/locals.lua
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@@ -360,6 +360,26 @@ do
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end
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+do
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+ -- bug in 5.4.4: 'break' may generate wrong 'close' instruction when
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+ -- leaving a loop block.
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+
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+ local closed = false
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+
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+ local o1 = setmetatable({}, {__close=function() closed = true end})
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+
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+ local function test()
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+ for k, v in next, {}, nil, o1 do
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+ local function f() return k end -- create an upvalue
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+ break
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+ end
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+ assert(closed)
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+ end
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+
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+ test()
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+end
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+
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+
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do print("testing errors in __close")
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-- original error is in __close
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