Igor’s Tip of the Week #126: Non-returning functions

Some functions in programs do not return to caller: well-known examples include C runtime functions like exit(), abort(), assert() but also many others. Modern compilers can exploit this knowledge to optimize the code better: for example, the code which would normally follow such a function call does not need to be generated which decreases the […]

Igor’s Tip of the Week #121: Limiting search to an address range

When performing a search in IDA, it by default starts from the current position and continues up to the maximum address in the database (or to the minimal for searches “Up”). This works well enough for small to average files, but can get pretty slow for big ones, or especially in case of debugging […]

Igor’s Tip of the Week #115: Set callee address

Cross-references is one of the most useful features of IDA. For example, they allow you to see where a particular function is being called or referenced from, helping you to see how the function is used and understand its behavior better or discover potential bugs or vulnerabilities. For direct calls, IDA adds cross-references automatically, […]

Igor’s tip of the week #105: Offsets with custom base

We’ve already covered simple offsets, where an operand value or a data value matches an address in the program and so can be directly converted to an offset. However, programs may also employ more complex, or indirect ways of referring to a location. One common approach is using a small offset from some predefined […]

Igor’s tip of the week #100: Collapsing pseudocode parts

When working with big functions in the decompiler, it may be useful to temporarily hide some parts of the pseudocode to analyze the rest. While currently it’s not possible to hide arbitrary lines like in disassembly, you can hide specific sections of it.   Collapsing local variable declarations While the local variable declarations are useful to see […]

Igor’s tip of the week #99: Enums

In IDA, an enum (from “enumeration”) is a set of symbolic constants with numerical values. They can be thought of as a superset of C/C++ enum types and preprocessor defines. These constants can be used in disassembly or pseudocode to replace specific numbers or their combinations with symbolic names, making the listing more readable and understandable.  Creating […]

Igor’s tip of the week #94: Variable-sized structures

Variable-sized structures is a construct used to handle binary structures of variable size with the advantage of compile-time type checking. In source code Usually such structures use a layout similar to following: struct varsize_t { // some fixed fields at the start int id; size_t datalen; //[more fields] unsigned char data[];// variable part }; In other words, a fixed-layout part at […]

Igor’s tip of the week #91: Item flags

When changing operand representation, you may need to check what are the operand types currently used by IDA for a specific instruction. In some cases it is obvious (e.g. for offset or character type), but the hex and default, for example, look exactly the same in most processors so it’s not easy to tell […]