Compiler Alias Analysis for Scope-Restricted Pointers
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Solution Overview
Problem
Current compilers face difficulties in effectively managing aliasing constraints for scope-restricted pointers, leading to suboptimal runtime performance due to challenges in representing and optimizing block-scope restricted pointers, which are often overlooked in favor of function-scope restricted pointers, resulting in inefficient code optimizations across function call boundaries.
Innovation Solution
A computer-implemented process that identifies an object and its scope, assigns a unique value, demarcates entrance and exit points, optimizes using aliasing information, and tracks state information to update the object, enabling more aggressive aliasing optimizations for restricted pointers within specific code regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If shadowing is used to represent scope-restricted aliasing, then aliasing precision is improved within function scope, but device complexity increases due to symbol explosion
Solution Approach 1:
The invention segments the program into regions with explicit scope boundaries (such as function scopes, blocks, or loops). Each region is independently analyzed for aliasing constraints, allowing the compiler to apply shadowing only within specific regions rather than globally. This segmentation limits the number of shadows created while maintaining precision where needed.
Solution Approach 2:
The invention applies different aliasing representations to different regions of the program. Within scope-restricted regions, shadowing is used to achieve precise aliasing information. Outside these regions, traditional aliasing analysis is used. This local differentiation optimizes the balance between precision and complexity by applying the more complex shadowing mechanism only where necessary.
2Measurement precision
If shadowing is used for restricted parameters, then aliasing refinement is achieved, but code optimization across function call boundaries becomes problematic
Solution Approach 1:
The invention performs preliminary identification of scope-restricted pointers and establishes their aliasing constraints before code generation and optimization passes. By pre-marking these pointers and their scopes, the compiler can later apply optimizations across function call boundaries with confidence that aliasing constraints are preserved, eliminating the need to保守ively restrict optimizations.
Solution Approach 2:
The invention introduces region markers or scope annotations as intermediary structures that carry aliasing information across function call boundaries. These intermediaries allow the compiler to track and preserve aliasing constraints through inlining and inter-procedural optimizations, bridging the gap between local shadowing precision and global optimization needs.
3Ease of manufacture
If traditional aliasing analysis is used, then implementation simplicity is maintained, but runtime performance is suboptimal due to conservative optimizations
Solution Approach 1:
The invention applies shadowing not universally to all pointers, but partially only to scope-restricted pointers that can benefit from it. This selective application maintains implementation simplicity for the majority of pointers while achieving performance improvements for the specific subset where scope restrictions enable more aggressive optimizations.
Solution Approach 2:
The invention changes the aliasing analysis parameters (creating shadows and setting flags) specifically for scope-restricted pointers, while leaving other pointers with traditional aliasing analysis. This parameter differentiation allows the compiler to achieve better runtime performance for restricted pointers without significantly increasing overall implementation complexity.
Data Source
AI summary
An illustrative embodiment of a computer-implemented process for managing aliasing constraints, identifies an object to form an identified object, identifies a scope of the identified object to form an identified scope, and assigns a unique value to the identified object within the identified scope. The computer-implemented process further demarcates an entrance to the identified scope, demarcates an exit to the identified scope, optimizes the identified object using a property of the identified scope and associated aliasing information, tracks the identified object state to form tracked state information; and uses the tracked state information to update the identified object.