Bug #12082: Tail-calling method can't catch exception raised by tail-called method - Ruby master - Ruby Issue Tracking System

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Bug #12082

closed

Tail-calling method can't catch exception raised by tail-called method

Added by rhenium (Kazuki Yamaguchi) almost 9 years ago. Updated over 8 years ago.

Status:

Closed

Assignee:

ko1 (Koichi Sasada)

Target version:

ruby -v:

Backport:

2.1: WONTFIX, 2.2: DONE, 2.3: DONE

[ruby-core:73871]

Description

The following code doesn't work as expected, on all versions of Ruby with tail call optimization (1.9.1 to 2.3.0).

def do_raise
  raise "should be rescued"
end
options = {
  tailcall_optimization: true,
  trace_instruction: false,
}
RubyVM::InstructionSequence.compile(<<EOF, __FILE__, __FILE__, __LINE__, options).eval
  def test_rescue
    return do_raise
    1 + 2
  rescue
    :ok
  end
EOF

p test_rescue # should print :ok, but raises "should be rescued"

Looks like nop instruction is (also) used to avoid this optimization (compile.c), but when doing early return, no nop is inserted.

I attached a (dirty) fix for this. Maybe there is a cleaner way.

Files

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0001-compile.c-don-t-do-tail-call-optimization-if-covered.patch (7.21 KB) 0001-compile.c-don-t-do-tail-call-optimization-if-covered.patch		rhenium (Kazuki Yamaguchi), 02/18/2016 04:34 AM
0001-compile.c-don-t-do-tail-call-optimization-if-covered-v2.patch (7.49 KB) 0001-compile.c-don-t-do-tail-call-optimization-if-covered-v2.patch		rhenium (Kazuki Yamaguchi), 03/09/2016 09:17 AM

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#1 [ruby-core:73873]

Updated by ko1 (Koichi Sasada) almost 9 years ago

Assignee set to ko1 (Koichi Sasada)

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#2 [ruby-core:74240]

Updated by rhenium (Kazuki Yamaguchi) almost 9 years ago

File 0001-compile.c-don-t-do-tail-call-optimization-if-covered-v2.patch 0001-compile.c-don-t-do-tail-call-optimization-if-covered-v2.patch added

Updating my patch, because it breaks such code:

def errinfo
  $!
end
RubyVM::InstructionSequence.compile(<<EOF, __FILE__, __FILE__, __LINE__, tailcall_optimization: true).eval
  def test_rescue
    raise "a"
  rescue
    errinfo
  end
EOF

p test_rescue # should return a RuntimeError