[llvm-dev] Is it possible to get the exact PC address of an instruction?

[Robinson, Paul via llvm-dev]

Hello Abhay,

Are you talking about fault injection at runtime?  With an instruction generated from C/C++ source?  I can imagine using a label in the source code, and finding the address of that label afterward, which limits you to the first instruction generated after the label.
But in the general case, if I had to do this myself, I’d probably end up disassembling the object file to find the instruction of interest; or generating asm source (with -S) and inserting a label before running it through the assembler.  None of these tactics do anything clever within LLVM, it would work with any toolchain.

Good luck,
--paulr

From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of Abhay Kamesh Potharaju via llvm-dev
Sent: Tuesday, June 9, 2020 11:16 AM
To: llvm-dev at lists.llvm.org
Subject: [llvm-dev] Is it possible to get the exact PC address of an instruction?

I wish to perform some instrumentation at a particular PC address/instruction using LLVM and I wished to know if getting the PC address of the instruction is in fact possible given the nature of the llvm compiler? For instance, I wish to inject a fault multiple times at the same instruction address and analyze this behavior. I wish to get the PC address of the instruction so as to be able to point to it as my injection target for all my runs.

Regards
Abhay Potharaju

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