Dead code

Finally, many complex software programs are modified or evolved from other programs. The result may be convoluted dead end pathways, nonfunctioning dead code, and inefficient module looping structures. Examination of code to determine the elegance or simphcity that avoids these non-parsimonious problems provides an important element in the evidence supporting continued reliabihty. 

Operating system code availability Software/hardware specifications Software/hardware design practices Product design records Program coding standards System development records System test records Programming tools Control of nonoperational software Removal of dead code ... 

Dead code elimination deletes code that never gets executed. For example,... 

Clearly, there is no need to synthesize an and gate since the assignment statement will never get executed and represents dead code. 

Ensuring that there is no redundant or dead code... 

Source code that has been deliberately commented mnst not be regarded as dead code since the compiler ignores it, and can never therefore become execntable instructions. 

In instances where software instmctions become dead code because of program modifications, these should be removed from the program before recompilation and submission to the production... 

Redundant bespoke (custom) programming is considered dead code and should be removed. The only exception is rednndant code strategically introdnced to try to protect the cotmnercial confidentiality of proprietary software, nsnally by confnsing disassemblers that might be used by unethical competitor organizations to reverse engineer the product. 

Identify any dead code (and where appropriate recommend removal)... 

Naming conventions for variables, symbols, programs, and files Annotation/commenfing/documentation conventions Display conventions (e.g., color standards, symbologies) Provisions for adherence to modular design principles Identification of approved languages or development software Provisions for elimination of dead code ... 

Verify the absence of dead code in source code... 

Dead code, which should be removed and an analysis performed to assess the effect and the need for reverification. 

Secondly, the checks run by the verifying compilers are usually not based on abstract interpretation. They are mostly realized as abstract syntax tree transformations much in the line with the supporting routines of the compilation process (data and control flow graph analysis, dead code elimination, register allocation, etc.) and the evaluation function is basically the matching of antipatterns of common programming bugs. 

The integration of various static analyzers into the HelenOS continuous integration process is underway. For the initial evaluation we have used Stanse [16] and Clang Analyzer [5]. Both of them showed to be moderately helpful to point out instances of unreachable dead code, use of language constructs which have ambiguous semantics in C and one case of possible NULL-pointer dereference. 

The adaptive strategy is less order-sensitive, and said to be the most useful one in practice. However, it may result in dead code (clauses that always lead to failure), namely when it relies on a clause yet unknown to be incorrect. Again, this is not a desirable behavior. 

Code motion, variable folding, dead code elimination, etc. Scheduling StokSS... 

Applies optimizing compiler transformations, including constant folding, common subexpression elimination, dead code elimination, loop retiming, loop pipelining, loop unrolling, and loop jamming. 

Uses various compiler transformations, including constant folding and dead code elimination. 

Similar to dead code elimination in optimizing compilers. Dead Vtbody Elimination removes a vtbody that is not called by other vtbodies. An automated version of the transformation is also available that removes all vtbodies not called by others. For example, applying Dead Vtbody Elimination to the VT on the right side of Figure 3-2 would remove vtbody V2 B, which is no longer referenced by other vtbodies. This transformation is typically applied after Vtbody Inline Expansion. 

Flow Analysis This phase uses classical flow analysis algorithms [Aho86] to analyze the lifetimes of variables, to determine live and dead variables, and to eliminate dead code. In the general synthesis path, dead code elimination is performed by the transformations, and lifetime analysis is performed by EMUCS. 

Further reviews (e.g. dead code, test coverage adequacy, behavior of algorithms) and traceability to the software design requirements ... 

Read in your HDL code using the read command with the appropriate options. The read command performs syntax checking and basic code optimization such as, constant propagation and dead-code elimination before creating a network of logic equations and registers. 

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