diff --git a/docs/Passes.html b/docs/Passes.html new file mode 100644 index 00000000000..fa6e22fedff --- /dev/null +++ b/docs/Passes.html @@ -0,0 +1,984 @@ + + + + LLVM's Analysis and Transform Passes + + + + +
LLVM's Analysis and Transform Passes
+ +
    +
  1. Introduction
    2. +
  2. Analysis Passes +
  3. Transform Passes
    4. +
  4. Utility Passes
    5. +
+ +
+

Written by Reid Spencer

+
+ + +
Introduction
+
+

This document serves as a high level summary of the optimization features + that LLVM provides. Optimizations are implemented as Passes that traverse some + portion of a program to either collect information or transform the program. + THe table below divides the passes that LLVM provides into three categories. + Analysis passes compute information that other passes can use or for debugging + or program visualization purposes. Transform passes can use (or invalidate) + the analysis passes. Transform passes all mutate the program in some way. + Utility passes provides ome utility but don't otherwise fit categorization. + For example passes to extract functions to bytecode or write a module to + bytecode are neither analysis nor transform passes. +

The table below provides a quick summary of each pass and links to the more + complete pass description later in the document.

+
+
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
ANALYSIS PASSES
OptionNameDirectory
-aa-evalExhaustive Alias Analysis Precision Evaluator
-anders-aaAndersen's Interprocedural Alias Analysis
-basicaaBasic Alias Analysis (default AA impl)
-basiccgBasic CallGraph Construction
-basicvnBasic Value Numbering (default GVN impl)
-callgraphPrint a call graph
-callsccPrint SCCs of the Call Graph
-cfgsccPrint SCCs of each function CFG
-count-aaCount Alias Analysis Query Responses
-debug-aaAA use debugger
-domfrontierDominance Frontier Construction
-domsetDominator Set Construction
-domtreeDominator Tree Construction
-etforestET Forest Construction
-externalfnconstantsPrint external fn callsites passed constants
-globalsmodref-aaSimple mod/ref analysis for globals
-idomImmediate Dominators Construction
-instcountCounts the various types of Instructions
-intervalsInterval Partition Construction
-load-vnLoad Value Numbering
-loopsNatural Loop Construction
-no-aaNo Alias Analysis (always returns 'may' alias)
-no-profileNo Profile Information
-postdomfrontierPost-Dominance Frontier Construction
-postdomsetPost-Dominator Set Construction
-postdomtreePost-Dominator Tree Construction
-postetforestPost-ET-Forest Construction
-postidomImmediate Post-Dominators Construction
-printPrint function to stderr
-print-alias-setsAlias Set Printer
-print-callgraphPrint Call Graph to 'dot' file
-print-cfgPrint CFG of function to 'dot' file
-print-cfg-onlyPrint CFG of function to 'dot' file (with no function bodies)
-printmPrint module to stderr
-printusedtypesFind Used Types
-profile-loaderLoad profile information from llvmprof.out
-scalar-evolutionScalar Evolution Analysis
-targetdataTarget Data Layout
TRANSFORM PASSES
OptionNameDirectory
-adceAggressive Dead Code Elimination
-argpromotionPromote 'by reference' arguments to scalars
-block-placementProfile Guided Basic Block Placement
-break-crit-edgesBreak Critical Edges in CFG
-ceeCorrelated Expression Elimination
-condpropConditional Propagation
-constmergeMerge Duplicate Global Constants
-constpropSimple constant propagation
-dceDead Code Elimination
-deadargelimDead Argument Elimination
-deadtypeelimDead Type Elimination
-dieDead Instruction Elimination
-dseDead Store Elimination
-gcseGlobal Common Subexpression Elimination
-globaldceDead Global Elimination
-globaloptGlobal Variable Optimizer
-indmemremIndirect Malloc and Free Removal
-indvarsCanonicalize Induction Variables
-inlineFunction Integration/Inlining
-insert-block-profilingInsert instrumentation for block profiling
-insert-edge-profilingInsert instrumentation for edge profiling
-insert-function-profilingInsert instrumentation for function profiling
-insert-null-profiling-rsMeasure profiling framework overhead
-insert-rs-profiling-frameworkInsert random sampling instrumentation framework
-instcombineCombine redundant instructions
-internalizeInternalize Global Symbols
-ipconstpropInterprocedural constant propagation
-ipsccpInterprocedural Sparse Conditional Constant Propagation
-lcssaLoop-Closed SSA Form Pass
-licmLoop Invariant Code Motion
-loop-extractExtract loops into new functions
-loop-extract-singleExtract at most one loop into a new function
-loop-reduceLoop Strength Reduction
-loop-unrollUnroll Loops
-loop-unswitchUnswitch Loops
-loopsimplifyCanonicalize Natural Loops
-lower-packedLower Packed Operations
-lowerallocsLower allocations from instructions to calls
-lowergcLower GC intrinsics, for GCless code generators
-lowerinvokeLower Invoke and Unwind
-lowerselectLower Selects To Branches
-lowersetjmpLower Set Jump
-lowerswitchLower SwitchInst's to branches
-mem2regPromote Memory to Register
-mergereturnUnify Function Exit Nodes
-predsimplifyPredicate Simplifier
-prune-ehRemove unused exception handling info
-raiseallocsRaise allocations from calls to instructions
-reassociateReassociate Expressions
-reg2memDemote Values to Memory
-scalarreplScalar Replacement of Aggregates
-sccpSparse Conditional Constant Propagation
-simplify-libcallsSimplify well-known library calls
-simplifycfgSimplify the CFG
-stripStrip all symbols from a module
-tailcallelimTail Call Elimination
-tailduplicateTail Duplication
UTILITY PASSES
OptionNameDirectory
-deadarghaX0rDead Argument Hacking (BUGPOINT ONLY)
-extract-blocksExtract Basic Blocks From Module (BUGPOINT ONLY)
-emitbytecodeBytecode Writer
-verifyModule Verifier
+
+ + +
Analysis Passes
+
+

This section describes the LLVM Analysis Passes.

+
+ + +
+ Exhaustive Alias Analysis Precision Evaluator +
+
+

Yet to be written.

+
+ + +
+ Andersen's Interprocedural Alias Analysis +
+
+

Yet to be written.

+
+ + +
+ Basic Alias Analysis +
+
+

Yet to be written.

+
+ + +
+ Basic Call Graph Construction +
+
+

Yet to be written.

+
+ + +
+ Basic Value Numbering +
+
+

Yet to be written.

+
+ + +
+ Print Call Graph +
+
+

Yet to be written.

+
+ + +
+ Print SCCs of the Call Graph +
+
+

Yet to be written.

+
+ + +
+ Print SCCs of each Function Control Flow Graph +
+
+

Yet to be written.

+
+ + +
+ Count Alias Analysis Query Responses +
+
+

Yet to be written.

+
+ + +
+ Alias Analysis Usage Debugger +
+
+

Yet to be written.

+
+ + +
+ Dominance Frontier Construction +
+
+

Yet to be written.

+
+ + +
+ Dominator Set Construction +
+
+

Yet to be written.

+
+ + +
+ Dominator Tree Construction +
+
+

Yet to be written.

+
+ + +
+ ET Forest Construction +
+
+

Yet to be written.

+
+ + +
+ Basic Value Numbering +
+
+

Yet to be written.

+
+ + +
+ Print external fn callsites passed constants +
+
+

Yet to be written.

+
+ + +
+ Simple mod/ref analysis for globals +
+
+

Yet to be written.

+
+ + +
+ Immediate Dominators Construction +
+
+

Yet to be written.

+
+ + +
+ Counts the various types of Instructions +
+
+

Yet to be written.

+
+ + +
+ Interval Partition Construction +
+
+

Yet to be written.

+
+ + +
+ Load Value Numbering +
+
+

Yet to be written.

+
+ + +
+ Natural Loop Construction +
+
+

Yet to be written.

+
+ + +
+ No Alias Analysis (always returns 'may' alias) +
+
+

Yet to be written.

+
+ + +
+ No Profile Information +
+
+

Yet to be written.

+
+ + +
+ Post-Dominance Frontier Construction +
+
+

Yet to be written.

+
+ + +
+ Post-Dominator Set Construction +
+
+

Yet to be written.

+
+ + +
+ Post-Dominator Tree Construction +
+
+

Yet to be written.

+
+ + +
+ Post-ET-Forest Construction +
+
+

Yet to be written.

+
+ + +
+ Immediate Post-Dominators Construction +
+
+

Yet to be written.

+
+ + +
+ Print function to stderr +
+
+

Yet to be written.

+
+ + +
+ Alias Set Printer +
+
+

Yet to be written.

+
+ + +
+ Print Call Graph to 'dot' file +
+
+

Yet to be written.

+
+ + +
+ Print CFG of function to 'dot' file +
+
+

Yet to be written.

+
+ + +
+ Print CFG of function to 'dot' file (with no function bodies) +
+
+

Yet to be written.

+
+ + +
+ Print module to stderr +
+
+

Yet to be written.

+
+ + +
+ Find Used Types +
+
+

Yet to be written.

+
+ + +
+ Load profile information from llvmprof.out +
+
+

Yet to be written.

+
+ + +
+ Scalar Evolution Analysis +
+
+

Yet to be written.

+
+ + +
+ Target Data Layout +
+
+

Yet to be written.

+
+ + +
Transform Passes
+
+

This section describes the LLVM Transform Passes.

+
+ + +
+ Aggressive Dead Code Elimination +
+
+

Yet to be written.

+
+ + +
+ Promote 'by reference' arguments to scalars +
+
+

Yet to be written.

+
+ + +
+ Profile Guided Basic Block Placement +
+
+

Yet to be written.

+
+ + +
+ Break Critical Edges in CFG +
+
+

Yet to be written.

+
+ + +
+ Correlated Expression Elimination +
+
+

Yet to be written.

+
+ + +
+ Conditional Propagation +
+
+

Yet to be written.

+
+ + +
+ Merge Duplicate Global Constants +
+
+

Yet to be written.

+
+ + +
+ Simple constant propagation +
+
+

Yet to be written.

+
+ + +
+ Dead Code Elimination +
+
+

Yet to be written.

+
+ + +
+ Dead Argument Elimination +
+
+

Yet to be written.

+
+ + +
+ Dead Type Elimination +
+
+

Yet to be written.

+
+ + +
+ Dead Instruction Elimination +
+
+

Yet to be written.

+
+ + +
+ Dead Store Elimination +
+
+

Yet to be written.

+
+ + +
+ Global Common Subexpression Elimination +
+
+

Yet to be written.

+
+ + +
+ Dead Global Elimination +
+
+

Yet to be written.

+
+ + +
+ Global Variable Optimizer +
+
+

Yet to be written.

+
+ + +
+ Indirect Malloc and Free Removal +
+
+

Yet to be written.

+
+ + +
+ Canonicalize Induction Variables +
+
+

Yet to be written.

+
+ + +
+ Function Integration/Inlining +
+
+

Yet to be written.

+
+ + +
+ Insert instrumentation for block profiling +
+
+

Yet to be written.

+
+ + +
+ Insert instrumentation for edge profiling +
+
+

Yet to be written.

+
+ + +
+ Insert instrumentation for function profiling +
+
+

Yet to be written.

+
+ + +
+ Measure profiling framework overhead +
+
+

Yet to be written.

+
+ + +
+ Insert random sampling instrumentation framework +
+
+

Yet to be written.

+
+ + +
+ Combine redundant instructions +
+
+

Yet to be written.

+
+ + +
+ Internalize Global Symbols +
+
+

Yet to be written.

+
+ + +
+ Interprocedural constant propagation +
+
+

Yet to be written.

+
+ + +
+ Interprocedural Sparse Conditional Constant Propagation +
+
+

Yet to be written.

+
+ + +
+ Loop-Closed SSA Form Pass +
+
+

Yet to be written.

+
+ + +
+ Loop Invariant Code Motion +
+
+

Yet to be written.

+
+ + +
+ Extract loops into new functions +
+
+

Yet to be written.

+
+ + +
+ Extract at most one loop into a new function +
+
+

Yet to be written.

+
+ + +
+ Loop Strength Reduction +
+
+

Yet to be written.

+
+ + +
+ Unroll Loops +
+
+

Yet to be written.

+
+ + +
+ Unswitch Loops +
+
+

Yet to be written.

+
+ + +
+ Canonicalize Natural Loops +
+
+

Yet to be written.

+
+ + +
+ Lower Packed Operations +
+
+

Yet to be written.

+
+ + +
+ Lower allocations from instructions to calls +
+
+

Yet to be written.

+
+ + +
+ Lower GC intrinsics, for GCless code generators +
+
+

Yet to be written.

+
+ + +
+ Lower Invoke and Unwind +
+
+

Yet to be written.

+
+ + +
+ Lower Selects To Branches +
+
+

Yet to be written.

+
+ + +
+ Lower Set Jump +
+
+

Yet to be written.

+
+ + +
+ Lower SwitchInst's to branches +
+
+

Yet to be written.

+
+ + +
+ Promote Memory to Register +
+
+

Yet to be written.

+
+ + +
+ Unify Function Exit Nodes +
+
+

Yet to be written.

+
+ + +
+ Predicate Simplifier +
+
+

Yet to be written.

+
+ + +
+ Remove unused exception handling info +
+
+

Yet to be written.

+
+ + +
+ Raise allocations from calls to instructions +
+
+

Yet to be written.

+
+ + +
+ Reassociate Expressions +
+
+

Yet to be written.

+
+ + +
+ Demote Values to Memory +
+
+

Yet to be written.

+
+ + +
+ Scalar Replacement of Aggregates +
+
+

Yet to be written.

+
+ + +
+ Sparse Conditional Constant Propagation +
+
+

Yet to be written.

+
+ + +
+ Simplify well-known library calls +
+
+

Yet to be written.

+
+ + +
+ Simplify the CFG +
+
+

Yet to be written.

+
+ + +
+ Strip all symbols from a module +
+
+

Yet to be written.

+
+ + +
+ Tail Call Elimination +
+
+

Yet to be written.

+
+ + +
+ Tail Duplication +
+
+

Yet to be written.

+
+ + +
Utility Passes
+
+

This section describes the LLVM Utility Passes.

+
+ + +
+ Dead Argument Hacking (BUGPOINT ONLY) +
+
+

Yet to be written.

+
+ + +
+ Extract Basic Blocks From Module (BUGPOINT ONLY) +
+
+

Yet to be written.

+
+ + +
+ Bytecode Writer +
+
+

Yet to be written.

+
+ + +
+ Module Verifier +
+
+

Yet to be written.

+
+ + + +
+
+ Valid CSS! + Valid HTML 4.01! + + Reid Spencer
+ LLVM Compiler Infrastructure
+ Last modified: $Date$ +
+ + +