If the previous instruction is not a leaf instruction, then the PC was
incremented before the instruction was ran (meaning the currently
executing instruction is actually the previous instruction), so we
should not increment the PC otherwise we will calculate the source
line for the next instruction.
This bug can be reproduced in the following script:
```
require "objspace"
ObjectSpace.trace_object_allocations_start
a =
1.0 / 0.0
p [ObjectSpace.allocation_sourceline(a), ObjectSpace.allocation_sourcefile(a)]
```
Which outputs: [4, "test.rb"]
This is incorrect because the object was allocated on line 10 and not
line 4. The behaviour is correct when we use a leaf instruction (e.g.
if we replaced `1.0 / 0.0` with `"hello"`), then the output is:
[10, "test.rb"].
[Bug #19456]
Use ID instead of GENTRY for gvars.
Global variables are compiled into GENTRY (a pointer to struct
rb_global_entry). This patch replace this GENTRY to ID and
make the code simple.
We need to search GENTRY from ID every time (st_lookup), so
additional overhead will be introduced.
However, the performance of accessing global variables is not
important now a day and this simplicity helps Ractor development.
Fixes [Bug #16332]
Constant access was changed to no longer allow top-level constant access
through `nil`, but `defined?` wasn't changed at the same time to stay
consistent.
Use a separate defined type to distinguish between a constant
referenced from the current lexical scope and one referenced from
another namespace.
If a function has rb_warning() that is not a leaf because warning
ultimately is a method call of Warning#warn.
If a function has rb_name_error() that is not a leaf because
NameError is allocated, then initialized. This of course
involves calling NameError#initialize.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66976 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
These erb files are in fact erb comments + plain C. Adding #line
help us debug in case we have trouble there.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66572 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
An instruction is leaf if it has no rb_funcall inside. In order to
check this property, we introduce stack canary which is a random
number collected at runtime. Stack top is always filled with this
number and checked for stack smashing operations, when VM_CHECK_MODE.
[GH-1947]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64677 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
