The flag checks that translate `break N` / `continue N` were emitted only
at the end of each enclosing loop body. After the inner construct exited
with the countdown flag set, every trailing statement of the enclosing
body still executed before the check ran:
foreach ([1] as $x) {
foreach ([1] as $y) { break 2; }
echo "leaked"; // ran in compiled output, not in PHP
}
The native (int-typed) switch path was worse: its check sat inside the
do-while(0) wrapper, decrementing the flag a second time for the switch
level the C++ `break` had already exited. A `break 2` from a native
switch inside a loop therefore never exited the loop at all.
Emit the propagation check immediately after every nested loop / switch
statement instead, from the statement dispatcher, and drop the dead
end-of-body emissions. The check now also distinguishes the enclosing
construct: when it sits inside a switch, a continue that lands on the
switch level lowers to `break`, matching PHP's continue-targets-switch
semantics.
parseBreak/parseContinue now reject levels exceeding the number of
enclosing breakable constructs - the same compile-time validation PHP
performs (`Cannot 'break' 2 levels`) - which the countdown scheme
relies on to terminate at an enclosing construct.
The continue-2-while scenario in break-continue-level.phpt encoded the
old leaked behavior: its `$i++` after the inner loop only ran because of
the misplaced check; standard PHP loops forever on it. The counter now
advances before the inner loop.
master^2
Alessio Giacobbe
parent
a44fd22e50
commit
9fd46c22e3
7 changed files with 223 additions and 38 deletions
@ -0,0 +1,155 @@ |
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--TEST-- |
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Multi-level break/continue must skip trailing statements of enclosing bodies |
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--FILE-- |
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<?php |
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|
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function nativeSwitchBreak(int $n): void |
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{ |
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// break 2 from a native (int-typed) switch inside a loop must exit the loop |
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for ($i = 0; $i < 3; $i++) { |
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echo "n-iter $i\n"; |
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switch ($n) { |
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case 1: |
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echo "n-case\n"; |
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break 2; |
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default: |
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break; |
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} |
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echo "n-after $i\n"; |
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} |
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echo "native-switch-break-2: done\n"; |
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} |
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|
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function main(): void |
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{ |
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// break 2: statements after the inner loop must not run |
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foreach ([1, 2, 3] as $x) { |
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foreach ([1, 2, 3] as $y) { |
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echo "b2 inner $x.$y\n"; |
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break 2; |
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} |
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echo "b2 leaked $x\n"; |
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} |
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echo "break-2: done\n"; |
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|
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// continue 2: statements after the inner loop must not run |
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foreach ([1, 2] as $x) { |
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foreach ([1, 2] as $y) { |
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echo "c2 inner $x.$y\n"; |
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continue 2; |
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} |
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echo "c2 leaked $x\n"; |
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} |
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echo "continue-2: done\n"; |
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|
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// break 2 from a switch inside a loop: statements after the switch |
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// must not run and the loop must exit |
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for ($i = 0; $i < 3; $i++) { |
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echo "sw iter $i\n"; |
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switch ($i) { |
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case 1: |
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echo "sw case $i\n"; |
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break 2; |
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default: |
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break; |
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} |
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echo "sw after $i\n"; |
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} |
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echo "switch-break-2: done\n"; |
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|
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// continue 2 from a switch inside a loop targets the loop |
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for ($i = 0; $i < 3; $i++) { |
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switch ($i) { |
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case 1: |
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echo "swc case $i\n"; |
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continue 2; |
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default: |
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break; |
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} |
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echo "swc after $i\n"; |
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} |
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echo "switch-continue-2: done\n"; |
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|
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// break 3 from a loop inside a switch inside a loop |
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for ($i = 0; $i < 3; $i++) { |
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switch ($i) { |
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case 0: |
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foreach ([1, 2] as $y) { |
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echo "b3 deep $i.$y\n"; |
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break 3; |
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} |
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echo "b3 leaked after deep loop\n"; |
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break; |
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default: |
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echo "b3 leaked default\n"; |
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break; |
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} |
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echo "b3 leaked after switch $i\n"; |
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} |
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echo "break-3-through-switch: done\n"; |
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|
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// continue 2 from a loop inside a switch acts as break on the switch |
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// level: statements after the switch must still run |
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for ($i = 0; $i < 2; $i++) { |
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switch ($i) { |
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case 0: |
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foreach ([1, 2] as $y) { |
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echo "c2s deep $i.$y\n"; |
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continue 2; |
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} |
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echo "c2s leaked after deep loop\n"; |
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break; |
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default: |
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break; |
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} |
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echo "c2s after switch $i\n"; |
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} |
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echo "continue-2-targets-switch: done\n"; |
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|
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// continue 3 propagates through a switch up to the outer loop |
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for ($i = 0; $i < 2; $i++) { |
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switch ($i) { |
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case 0: |
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foreach ([1, 2] as $y) { |
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echo "c3 deep $i.$y\n"; |
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continue 3; |
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} |
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echo "c3 leaked after deep loop\n"; |
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break; |
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default: |
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break; |
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} |
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echo "c3 after switch $i\n"; |
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} |
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echo "continue-3-through-switch: done\n"; |
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|
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nativeSwitchBreak(1); |
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} |
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?> |
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--EXPECT-- |
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b2 inner 1.1 |
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break-2: done |
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c2 inner 1.1 |
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c2 inner 2.1 |
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continue-2: done |
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sw iter 0 |
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sw after 0 |
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sw iter 1 |
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sw case 1 |
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switch-break-2: done |
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swc after 0 |
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swc case 1 |
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swc after 2 |
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switch-continue-2: done |
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b3 deep 0.1 |
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break-3-through-switch: done |
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c2s deep 0.1 |
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c2s after switch 0 |
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c2s after switch 1 |
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continue-2-targets-switch: done |
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c3 deep 0.1 |
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c3 after switch 1 |
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continue-3-through-switch: done |
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n-iter 0 |
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n-case |
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native-switch-break-2: done |
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