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On 11/21/11 6:35 AM, Deu Arm wrote:
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Hi everybody,
<div><br>
</div>
<div>I am writing an LLVM pass and I want to iterate over the
whole module (including global variables), that's why I use
ModulePass instead of FunctionPass. But I don't know how to do
it. Using Module::iterator seams to iterate only over functions.
But I need to iterate over all the Instructions in the module.
How should I do such an iteration?</div>
</blockquote>
<br>
To iterate over all the instructions, you need essentially need to
do the following:<br>
<br>
for all Functions F in Module M)<br>
for all Basic Blocks BB in Function F<br>
for all Instructions I in Basic Block BB<br>
do_something_with I<br>
<br>
That said, if you need to process certain instructions within the
module, the best thing to do is to make your pass inherit from the
InstVisitor<> class
(<a class="moz-txt-link-freetext" href="http://llvm.org/doxygen/classllvm_1_1InstCombiner.html">http://llvm.org/doxygen/classllvm_1_1InstCombiner.html</a>). You
basically inherit from InstVisitor like so:<br>
<br>
class MyPass : public ModulePass, InstVisitor<MyPass> {<br>
...<br>
}<br>
<br>
... and then implement a visit method for each type of instruction
that you want to handle. In your runOnModule() method, call
visit(M) to start iterating over every instruction in the Module.
The visit() method will call the appropriate visitXXX() method for
each instruction.<br>
<br>
For an example, see the Load/Store Instrumentation pass from
SAFECode:<br>
<br>
<a class="moz-txt-link-freetext" href="http://llvm.org/viewvc/llvm-project/safecode/trunk/lib/InsertPoolChecks/LoadStoreChecks.cpp?view=markup&pathrev=144620">http://llvm.org/viewvc/llvm-project/safecode/trunk/lib/InsertPoolChecks/LoadStoreChecks.cpp?view=markup&pathrev=144620</a><br>
<a class="moz-txt-link-freetext" href="http://llvm.org/viewvc/llvm-project/safecode/trunk/include/safecode/LoadStoreChecks.h?view=markup&pathrev=144620">http://llvm.org/viewvc/llvm-project/safecode/trunk/include/safecode/LoadStoreChecks.h?view=markup&pathrev=144620</a><br>
<br>
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cite="mid:CAAD26ec3BzNAp2KSmGdSa+Mptq97eyE4-ksQh4L8AEcUUuLaWw@mail.gmail.com"
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<div>Also, I would like to find all the "string" variables and do
some changes to them. But LLVM's IR language does not have such
a type. Tell me, please, what should I use.</div>
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<br>
Strings are usually encoded as GlobalVariable's. To find them, use
the global_begin() and global_end() iterators to iterate over all
GlobalVariables in the program. Strings are pointer to arrays of
type i8.<br>
<br>
-- John T.<br>
<br>
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cite="mid:CAAD26ec3BzNAp2KSmGdSa+Mptq97eyE4-ksQh4L8AEcUUuLaWw@mail.gmail.com"
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<div><br>
</div>
<div>Sincerely, </div>
<div>Shuhmacher</div>
<br>
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