<tr><th colspan="2"><b>ANALYSIS PASSES</b></th></tr>
<tr><th>Option</th><th>Name</th></tr>
<tr><td><a href="#aa-eval">-aa-eval</a></td><td>Exhaustive Alias Analysis Precision Evaluator</td></tr>
-<tr><td><a href="#anders-aa">-anders-aa</a></td><td>Andersen's Interprocedural Alias Analysis</td></tr>
<tr><td><a href="#basicaa">-basicaa</a></td><td>Basic Alias Analysis (default AA impl)</td></tr>
<tr><td><a href="#basiccg">-basiccg</a></td><td>Basic CallGraph Construction</td></tr>
-<tr><td><a href="#basicvn">-basicvn</a></td><td>Basic Value Numbering (default GVN impl)</td></tr>
-<tr><td><a href="#callgraph">-callgraph</a></td><td>Print a call graph</td></tr>
-<tr><td><a href="#callscc">-callscc</a></td><td>Print SCCs of the Call Graph</td></tr>
-<tr><td><a href="#cfgscc">-cfgscc</a></td><td>Print SCCs of each function CFG</td></tr>
<tr><td><a href="#codegenprepare">-codegenprepare</a></td><td>Optimize for code generation</td></tr>
<tr><td><a href="#count-aa">-count-aa</a></td><td>Count Alias Analysis Query Responses</td></tr>
<tr><td><a href="#debug-aa">-debug-aa</a></td><td>AA use debugger</td></tr>
<tr><td><a href="#domfrontier">-domfrontier</a></td><td>Dominance Frontier Construction</td></tr>
<tr><td><a href="#domtree">-domtree</a></td><td>Dominator Tree Construction</td></tr>
-<tr><td><a href="#externalfnconstants">-externalfnconstants</a></td><td>Print external fn callsites passed constants</td></tr>
+<tr><td><a href="#dot-callgraph">-dot-callgraph</a></td><td>Print Call Graph to 'dot' file</td></tr>
+<tr><td><a href="#dot-cfg">-dot-cfg</a></td><td>Print CFG of function to 'dot' file</td></tr>
+<tr><td><a href="#dot-cfg-only">-dot-cfg-only</a></td><td>Print CFG of function to 'dot' file (with no function bodies)</td></tr>
+<tr><td><a href="#dot-dom">-dot-dom</a></td><td>Print dominator tree of function to 'dot' file</td></tr>
+<tr><td><a href="#dot-dom-only">-dot-dom-only</a></td><td>Print dominator tree of function to 'dot' file (with no function bodies)</td></tr>
+<tr><td><a href="#dot-postdom">-dot-postdom</a></td><td>Print post dominator tree of function to 'dot' file</td></tr>
+<tr><td><a href="#dot-postdom-only">-dot-postdom-only</a></td><td>Print post dominator tree of function to 'dot' file (with no function bodies)</td></tr>
<tr><td><a href="#globalsmodref-aa">-globalsmodref-aa</a></td><td>Simple mod/ref analysis for globals</td></tr>
<tr><td><a href="#instcount">-instcount</a></td><td>Counts the various types of Instructions</td></tr>
<tr><td><a href="#intervals">-intervals</a></td><td>Interval Partition Construction</td></tr>
-<tr><td><a href="#load-vn">-load-vn</a></td><td>Load Value Numbering</td></tr>
<tr><td><a href="#loops">-loops</a></td><td>Natural Loop Construction</td></tr>
<tr><td><a href="#memdep">-memdep</a></td><td>Memory Dependence Analysis</td></tr>
<tr><td><a href="#no-aa">-no-aa</a></td><td>No Alias Analysis (always returns 'may' alias)</td></tr>
<tr><td><a href="#no-profile">-no-profile</a></td><td>No Profile Information</td></tr>
<tr><td><a href="#postdomfrontier">-postdomfrontier</a></td><td>Post-Dominance Frontier Construction</td></tr>
<tr><td><a href="#postdomtree">-postdomtree</a></td><td>Post-Dominator Tree Construction</td></tr>
-<tr><td><a href="#print">-print</a></td><td>Print function to stderr</td></tr>
<tr><td><a href="#print-alias-sets">-print-alias-sets</a></td><td>Alias Set Printer</td></tr>
-<tr><td><a href="#print-callgraph">-print-callgraph</a></td><td>Print Call Graph to 'dot' file</td></tr>
-<tr><td><a href="#print-cfg">-print-cfg</a></td><td>Print CFG of function to 'dot' file</td></tr>
-<tr><td><a href="#print-cfg-only">-print-cfg-only</a></td><td>Print CFG of function to 'dot' file (with no function bodies)</td></tr>
-<tr><td><a href="#printm">-printm</a></td><td>Print module to stderr</td></tr>
-<tr><td><a href="#printusedtypes">-printusedtypes</a></td><td>Find Used Types</td></tr>
+<tr><td><a href="#print-callgraph">-print-callgraph</a></td><td>Print a call graph</td></tr>
+<tr><td><a href="#print-callgraph-sccs">-print-callgraph-sccs</a></td><td>Print SCCs of the Call Graph</td></tr>
+<tr><td><a href="#print-cfg-sccs">-print-cfg-sccs</a></td><td>Print SCCs of each function CFG</td></tr>
+<tr><td><a href="#print-externalfnconstants">-print-externalfnconstants</a></td><td>Print external fn callsites passed constants</td></tr>
+<tr><td><a href="#print-function">-print-function</a></td><td>Print function to stderr</td></tr>
+<tr><td><a href="#print-module">-print-module</a></td><td>Print module to stderr</td></tr>
+<tr><td><a href="#print-used-types">-print-used-types</a></td><td>Find Used Types</td></tr>
<tr><td><a href="#profile-loader">-profile-loader</a></td><td>Load profile information from llvmprof.out</td></tr>
<tr><td><a href="#scalar-evolution">-scalar-evolution</a></td><td>Scalar Evolution Analysis</td></tr>
<tr><td><a href="#targetdata">-targetdata</a></td><td>Target Data Layout</td></tr>
<tr><td><a href="#argpromotion">-argpromotion</a></td><td>Promote 'by reference' arguments to scalars</td></tr>
<tr><td><a href="#block-placement">-block-placement</a></td><td>Profile Guided Basic Block Placement</td></tr>
<tr><td><a href="#break-crit-edges">-break-crit-edges</a></td><td>Break critical edges in CFG</td></tr>
-<tr><td><a href="#cee">-cee</a></td><td>Correlated Expression Elimination</td></tr>
-<tr><td><a href="#condprop">-condprop</a></td><td>Conditional Propagation</td></tr>
+<tr><td><a href="#codegenprepare">-codegenprepare</a></td><td>Prepare a function for code generation </td></tr>
<tr><td><a href="#constmerge">-constmerge</a></td><td>Merge Duplicate Global Constants</td></tr>
<tr><td><a href="#constprop">-constprop</a></td><td>Simple constant propagation</td></tr>
<tr><td><a href="#dce">-dce</a></td><td>Dead Code Elimination</td></tr>
<tr><td><a href="#deadtypeelim">-deadtypeelim</a></td><td>Dead Type Elimination</td></tr>
<tr><td><a href="#die">-die</a></td><td>Dead Instruction Elimination</td></tr>
<tr><td><a href="#dse">-dse</a></td><td>Dead Store Elimination</td></tr>
-<tr><td><a href="#gcse">-gcse</a></td><td>Global Common Subexpression Elimination</td></tr>
<tr><td><a href="#globaldce">-globaldce</a></td><td>Dead Global Elimination</td></tr>
<tr><td><a href="#globalopt">-globalopt</a></td><td>Global Variable Optimizer</td></tr>
<tr><td><a href="#gvn">-gvn</a></td><td>Global Value Numbering</td></tr>
-<tr><td><a href="#gvnpre">-gvnpre</a></td><td>Global Value Numbering/Partial Redundancy Elimination</td></tr>
<tr><td><a href="#indmemrem">-indmemrem</a></td><td>Indirect Malloc and Free Removal</td></tr>
<tr><td><a href="#indvars">-indvars</a></td><td>Canonicalize Induction Variables</td></tr>
<tr><td><a href="#inline">-inline</a></td><td>Function Integration/Inlining</td></tr>
<tr><td><a href="#internalize">-internalize</a></td><td>Internalize Global Symbols</td></tr>
<tr><td><a href="#ipconstprop">-ipconstprop</a></td><td>Interprocedural constant propagation</td></tr>
<tr><td><a href="#ipsccp">-ipsccp</a></td><td>Interprocedural Sparse Conditional Constant Propagation</td></tr>
+<tr><td><a href="#jump-threading">-jump-threading</a></td><td>Thread control through conditional blocks </td></tr>
<tr><td><a href="#lcssa">-lcssa</a></td><td>Loop-Closed SSA Form Pass</td></tr>
<tr><td><a href="#licm">-licm</a></td><td>Loop Invariant Code Motion</td></tr>
+<tr><td><a href="#loop-deletion">-loop-deletion</a></td><td>Dead Loop Deletion Pass </td></tr>
<tr><td><a href="#loop-extract">-loop-extract</a></td><td>Extract loops into new functions</td></tr>
<tr><td><a href="#loop-extract-single">-loop-extract-single</a></td><td>Extract at most one loop into a new function</td></tr>
<tr><td><a href="#loop-index-split">-loop-index-split</a></td><td>Index Split Loops</td></tr>
<tr><td><a href="#loop-unroll">-loop-unroll</a></td><td>Unroll loops</td></tr>
<tr><td><a href="#loop-unswitch">-loop-unswitch</a></td><td>Unswitch loops</td></tr>
<tr><td><a href="#loopsimplify">-loopsimplify</a></td><td>Canonicalize natural loops</td></tr>
-<tr><td><a href="#lower-packed">-lower-packed</a></td><td>lowers packed operations to operations on smaller packed datatypes</td></tr>
<tr><td><a href="#lowerallocs">-lowerallocs</a></td><td>Lower allocations from instructions to calls</td></tr>
-<tr><td><a href="#lowergc">-lowergc</a></td><td>Lower GC intrinsics, for GCless code generators</td></tr>
<tr><td><a href="#lowerinvoke">-lowerinvoke</a></td><td>Lower invoke and unwind, for unwindless code generators</td></tr>
-<tr><td><a href="#lowerselect">-lowerselect</a></td><td>Lower select instructions to branches</td></tr>
<tr><td><a href="#lowersetjmp">-lowersetjmp</a></td><td>Lower Set Jump</td></tr>
<tr><td><a href="#lowerswitch">-lowerswitch</a></td><td>Lower SwitchInst's to branches</td></tr>
<tr><td><a href="#mem2reg">-mem2reg</a></td><td>Promote Memory to Register</td></tr>
+<tr><td><a href="#memcpyopt">-memcpyopt</a></td><td>Optimize use of memcpy and friends</td></tr>
<tr><td><a href="#mergereturn">-mergereturn</a></td><td>Unify function exit nodes</td></tr>
-<tr><td><a href="#predsimplify">-predsimplify</a></td><td>Predicate Simplifier</td></tr>
<tr><td><a href="#prune-eh">-prune-eh</a></td><td>Remove unused exception handling info</td></tr>
-<tr><td><a href="#raiseallocs">-raiseallocs</a></td><td>Raise allocations from calls to instructions</td></tr>
<tr><td><a href="#reassociate">-reassociate</a></td><td>Reassociate expressions</td></tr>
<tr><td><a href="#reg2mem">-reg2mem</a></td><td>Demote all values to stack slots</td></tr>
<tr><td><a href="#scalarrepl">-scalarrepl</a></td><td>Scalar Replacement of Aggregates</td></tr>
<tr><td><a href="#simplify-libcalls">-simplify-libcalls</a></td><td>Simplify well-known library calls</td></tr>
<tr><td><a href="#simplifycfg">-simplifycfg</a></td><td>Simplify the CFG</td></tr>
<tr><td><a href="#strip">-strip</a></td><td>Strip all symbols from a module</td></tr>
+<tr><td><a href="#strip-dead-prototypes">-strip-dead-prototypes</a></td><td>Remove unused function declarations</td></tr>
+<tr><td><a href="#sretpromotion">-sretpromotion</a></td><td>Promote sret arguments</td></tr>
<tr><td><a href="#tailcallelim">-tailcallelim</a></td><td>Tail Call Elimination</td></tr>
<tr><td><a href="#tailduplicate">-tailduplicate</a></td><td>Tail Duplication</td></tr>
<tr><th>Option</th><th>Name</th></tr>
<tr><td><a href="#deadarghaX0r">-deadarghaX0r</a></td><td>Dead Argument Hacking (BUGPOINT USE ONLY; DO NOT USE)</td></tr>
<tr><td><a href="#extract-blocks">-extract-blocks</a></td><td>Extract Basic Blocks From Module (for bugpoint use)</td></tr>
-<tr><td><a href="#emitbitcode">-emitbitcode</a></td><td>Bitcode Writer</td></tr>
+<tr><td><a href="#preverify">-preverify</a></td><td>Preliminary module verification</td></tr>
<tr><td><a href="#verify">-verify</a></td><td>Module Verifier</td></tr>
<tr><td><a href="#view-cfg">-view-cfg</a></td><td>View CFG of function</td></tr>
<tr><td><a href="#view-cfg-only">-view-cfg-only</a></td><td>View CFG of function (with no function bodies)</td></tr>
+<tr><td><a href="#view-dom">-view-dom</a></td><td>View dominator tree of function</td></tr>
+<tr><td><a href="#view-dom-only">-view-dom-only</a></td><td>View dominator tree of function (with no function bodies)</td></tr>
+<tr><td><a href="#view-postdom">-view-postdom</a></td><td>View post dominator tree of function</td></tr>
+<tr><td><a href="#view-postdom-only">-view-postdom-only</a></td><td>View post dominator tree of function (with no function bodies)</td></tr>
</table>
</div>
Spadini, and Wojciech Stryjewski.</p>
</div>
-<!-------------------------------------------------------------------------- -->
-<div class="doc_subsection">
- <a name="anders-aa">Andersen's Interprocedural Alias Analysis</a>
-</div>
-<div class="doc_text">
- <p>
- This is an implementation of Andersen's interprocedural alias
- analysis
- </p>
-
- <p>
- In pointer analysis terms, this is a subset-based, flow-insensitive,
- field-sensitive, and context-insensitive algorithm pointer algorithm.
- </p>
-
- <p>
- This algorithm is implemented as three stages:
- </p>
-
- <ol>
- <li>Object identification.</li>
- <li>Inclusion constraint identification.</li>
- <li>Offline constraint graph optimization.</li>
- <li>Inclusion constraint solving.</li>
- </ol>
-
- <p>
- The object identification stage identifies all of the memory objects in the
- program, which includes globals, heap allocated objects, and stack allocated
- objects.
- </p>
-
- <p>
- The inclusion constraint identification stage finds all inclusion constraints
- in the program by scanning the program, looking for pointer assignments and
- other statements that effect the points-to graph. For a statement like
- <code><var>A</var> = <var>B</var></code>, this statement is processed to
- indicate that <var>A</var> can point to anything that <var>B</var> can point
- to. Constraints can handle copies, loads, and stores, and address taking.
- </p>
-
- <p>
- The offline constraint graph optimization portion includes offline variable
- substitution algorithms intended to computer pointer and location
- equivalences. Pointer equivalences are those pointers that will have the
- same points-to sets, and location equivalences are those variables that
- always appear together in points-to sets.
- </p>
-
- <p>
- The inclusion constraint solving phase iteratively propagates the inclusion
- constraints until a fixed point is reached. This is an O(<var>n</var>³)
- algorithm.
- </p>
-
- <p>
- Function constraints are handled as if they were structs with <var>X</var>
- fields. Thus, an access to argument <var>X</var> of function <var>Y</var> is
- an access to node index <code>getNode(<var>Y</var>) + <var>X</var></code>.
- This representation allows handling of indirect calls without any issues. To
- wit, an indirect call <code><var>Y</var>(<var>a</var>,<var>b</var>)</code> is
- equivalent to <code>*(<var>Y</var> + 1) = <var>a</var>, *(<var>Y</var> + 2) =
- <var>b</var></code>. The return node for a function <var>F</var> is always
- located at <code>getNode(<var>F</var>) + CallReturnPos</code>. The arguments
- start at <code>getNode(<var>F</var>) + CallArgPos</code>.
- </p>
-</div>
-
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="basicaa">Basic Alias Analysis (default AA impl)</a>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="basicvn">Basic Value Numbering (default GVN impl)</a>
+ <a name="codegenprepare">Optimize for code generation</a>
</div>
<div class="doc_text">
<p>
- This is the default implementation of the <code>ValueNumbering</code>
- interface. It walks the SSA def-use chains to trivially identify
- lexically identical expressions. This does not require any ahead of time
- analysis, so it is a very fast default implementation.
+ This pass munges the code in the input function to better prepare it for
+ SelectionDAG-based code generation. This works around limitations in it's
+ basic-block-at-a-time approach. It should eventually be removed.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="callgraph">Print a call graph</a>
+ <a name="count-aa">Count Alias Analysis Query Responses</a>
</div>
<div class="doc_text">
<p>
- This pass, only available in <code>opt</code>, prints the call graph to
- standard output in a human-readable form.
+ A pass which can be used to count how many alias queries
+ are being made and how the alias analysis implementation being used responds.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="callscc">Print SCCs of the Call Graph</a>
+ <a name="debug-aa">AA use debugger</a>
</div>
<div class="doc_text">
<p>
- This pass, only available in <code>opt</code>, prints the SCCs of the call
- graph to standard output in a human-readable form.
+ This simple pass checks alias analysis users to ensure that if they
+ create a new value, they do not query AA without informing it of the value.
+ It acts as a shim over any other AA pass you want.
+ </p>
+
+ <p>
+ Yes keeping track of every value in the program is expensive, but this is
+ a debugging pass.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="cfgscc">Print SCCs of each function CFG</a>
+ <a name="domfrontier">Dominance Frontier Construction</a>
</div>
<div class="doc_text">
<p>
- This pass, only available in <code>opt</code>, prints the SCCs of each
- function CFG to standard output in a human-readable form.
+ This pass is a simple dominator construction algorithm for finding forward
+ dominator frontiers.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="codegenprepare">Optimize for code generation</a>
+ <a name="domtree">Dominator Tree Construction</a>
</div>
<div class="doc_text">
<p>
- This pass munges the code in the input function to better prepare it for
- SelectionDAG-based code generation. This works around limitations in it's
- basic-block-at-a-time approach. It should eventually be removed.
+ This pass is a simple dominator construction algorithm for finding forward
+ dominators.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="count-aa">Count Alias Analysis Query Responses</a>
+ <a name="dot-callgraph">Print Call Graph to 'dot' file</a>
</div>
<div class="doc_text">
<p>
- A pass which can be used to count how many alias queries
- are being made and how the alias analysis implementation being used responds.
+ This pass, only available in <code>opt</code>, prints the call graph into a
+ <code>.dot</code> graph. This graph can then be processed with the "dot" tool
+ to convert it to postscript or some other suitable format.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="debug-aa">AA use debugger</a>
+ <a name="dot-cfg">Print CFG of function to 'dot' file</a>
</div>
<div class="doc_text">
<p>
- This simple pass checks alias analysis users to ensure that if they
- create a new value, they do not query AA without informing it of the value.
- It acts as a shim over any other AA pass you want.
+ This pass, only available in <code>opt</code>, prints the control flow graph
+ into a <code>.dot</code> graph. This graph can then be processed with the
+ "dot" tool to convert it to postscript or some other suitable format.
</p>
-
+</div>
+
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="dot-cfg-only">Print CFG of function to 'dot' file (with no function bodies)</a>
+</div>
+<div class="doc_text">
<p>
- Yes keeping track of every value in the program is expensive, but this is
- a debugging pass.
+ This pass, only available in <code>opt</code>, prints the control flow graph
+ into a <code>.dot</code> graph, omitting the function bodies. This graph can
+ then be processed with the "dot" tool to convert it to postscript or some
+ other suitable format.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="domfrontier">Dominance Frontier Construction</a>
+ <a name="dot-dom">Print dominator tree of function to 'dot' file</a>
</div>
<div class="doc_text">
<p>
- This pass is a simple dominator construction algorithm for finding forward
- dominator frontiers.
+ This pass, only available in <code>opt</code>, prints the dominator tree
+ into a <code>.dot</code> graph. This graph can then be processed with the
+ "dot" tool to convert it to postscript or some other suitable format.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="domtree">Dominator Tree Construction</a>
+ <a name="dot-dom-only">Print dominator tree of function to 'dot' file (with no
+ function bodies)</a>
</div>
<div class="doc_text">
<p>
- This pass is a simple dominator construction algorithm for finding forward
- dominators.
+ This pass, only available in <code>opt</code>, prints the dominator tree
+ into a <code>.dot</code> graph, omitting the function bodies. This graph can
+ then be processed with the "dot" tool to convert it to postscript or some
+ other suitable format.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="externalfnconstants">Print external fn callsites passed constants</a>
+ <a name="dot-postdom">Print post dominator tree of function to 'dot' file</a>
</div>
<div class="doc_text">
<p>
- This pass, only available in <code>opt</code>, prints out call sites to
- external functions that are called with constant arguments. This can be
- useful when looking for standard library functions we should constant fold
- or handle in alias analyses.
+ This pass, only available in <code>opt</code>, prints the post dominator tree
+ into a <code>.dot</code> graph. This graph can then be processed with the
+ "dot" tool to convert it to postscript or some other suitable format.
+ </p>
+</div>
+
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="dot-postdom-only">Print post dominator tree of function to 'dot' file
+ (with no function bodies)</a>
+</div>
+<div class="doc_text">
+ <p>
+ This pass, only available in <code>opt</code>, prints the post dominator tree
+ into a <code>.dot</code> graph, omitting the function bodies. This graph can
+ then be processed with the "dot" tool to convert it to postscript or some
+ other suitable format.
</p>
</div>
</p>
</div>
-<!-------------------------------------------------------------------------- -->
-<div class="doc_subsection">
- <a name="load-vn">Load Value Numbering</a>
-</div>
-<div class="doc_text">
- <p>
- This pass value numbers load and call instructions. To do this, it finds
- lexically identical load instructions, and uses alias analysis to determine
- which loads are guaranteed to produce the same value. To value number call
- instructions, it looks for calls to functions that do not write to memory
- which do not have intervening instructions that clobber the memory that is
- read from.
- </p>
-
- <p>
- This pass builds off of another value numbering pass to implement value
- numbering for non-load and non-call instructions. It uses Alias Analysis so
- that it can disambiguate the load instructions. The more powerful these base
- analyses are, the more powerful the resultant value numbering will be.
- </p>
-</div>
-
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="loops">Natural Loop Construction</a>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="print">Print function to stderr</a>
+ <a name="print-alias-sets">Alias Set Printer</a>
+</div>
+<div class="doc_text">
+ <p>Yet to be written.</p>
+</div>
+
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="print-callgraph">Print a call graph</a>
</div>
<div class="doc_text">
<p>
- The <code>PrintFunctionPass</code> class is designed to be pipelined with
- other <code>FunctionPass</code>es, and prints out the functions of the module
- as they are processed.
+ This pass, only available in <code>opt</code>, prints the call graph to
+ standard output in a human-readable form.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="print-alias-sets">Alias Set Printer</a>
+ <a name="print-callgraph-sccs">Print SCCs of the Call Graph</a>
</div>
<div class="doc_text">
- <p>Yet to be written.</p>
+ <p>
+ This pass, only available in <code>opt</code>, prints the SCCs of the call
+ graph to standard output in a human-readable form.
+ </p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="print-callgraph">Print Call Graph to 'dot' file</a>
+ <a name="print-cfg-sccs">Print SCCs of each function CFG</a>
</div>
<div class="doc_text">
<p>
- This pass, only available in <code>opt</code>, prints the call graph into a
- <code>.dot</code> graph. This graph can then be processed with the "dot" tool
- to convert it to postscript or some other suitable format.
+ This pass, only available in <code>opt</code>, prints the SCCs of each
+ function CFG to standard output in a human-readable form.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="print-cfg">Print CFG of function to 'dot' file</a>
+ <a name="print-externalfnconstants">Print external fn callsites passed constants</a>
</div>
<div class="doc_text">
<p>
- This pass, only available in <code>opt</code>, prints the control flow graph
- into a <code>.dot</code> graph. This graph can then be processed with the
- "dot" tool to convert it to postscript or some other suitable format.
+ This pass, only available in <code>opt</code>, prints out call sites to
+ external functions that are called with constant arguments. This can be
+ useful when looking for standard library functions we should constant fold
+ or handle in alias analyses.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="print-cfg-only">Print CFG of function to 'dot' file (with no function bodies)</a>
+ <a name="print-function">Print function to stderr</a>
</div>
<div class="doc_text">
<p>
- This pass, only available in <code>opt</code>, prints the control flow graph
- into a <code>.dot</code> graph, omitting the function bodies. This graph can
- then be processed with the "dot" tool to convert it to postscript or some
- other suitable format.
+ The <code>PrintFunctionPass</code> class is designed to be pipelined with
+ other <code>FunctionPass</code>es, and prints out the functions of the module
+ as they are processed.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="printm">Print module to stderr</a>
+ <a name="print-module">Print module to stderr</a>
</div>
<div class="doc_text">
<p>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="printusedtypes">Find Used Types</a>
+ <a name="print-used-types">Find Used Types</a>
</div>
<div class="doc_text">
<p>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="cee">Correlated Expression Elimination</a>
-</div>
-<div class="doc_text">
- <p>Correlated Expression Elimination propagates information from conditional
- branches to blocks dominated by destinations of the branch. It propagates
- information from the condition check itself into the body of the branch,
- allowing transformations like these for example:</p>
-
-<blockquote><pre>
-if (i == 7)
- ... 4*i; // constant propagation
-
-M = i+1; N = j+1;
-if (i == j)
- X = M-N; // = M-M == 0;
-</pre></blockquote>
-
- <p>This is called Correlated Expression Elimination because we eliminate or
- simplify expressions that are correlated with the direction of a branch. In
- this way we use static information to give us some information about the
- dynamic value of a variable.</p>
-</div>
-
-<!-------------------------------------------------------------------------- -->
-<div class="doc_subsection">
- <a name="condprop">Conditional Propagation</a>
+ <a name="codegenprepare">Prepare a function for code generation</a>
</div>
<div class="doc_text">
- <p>This pass propagates information about conditional expressions through the
- program, allowing it to eliminate conditional branches in some cases.</p>
+ This pass munges the code in the input function to better prepare it for
+ SelectionDAG-based code generation. This works around limitations in it's
+ basic-block-at-a-time approach. It should eventually be removed.
</div>
<!-------------------------------------------------------------------------- -->
</p>
</div>
-<!-------------------------------------------------------------------------- -->
-<div class="doc_subsection">
- <a name="gcse">Global Common Subexpression Elimination</a>
-</div>
-<div class="doc_text">
- <p>
- This pass is designed to be a very quick global transformation that
- eliminates global common subexpressions from a function. It does this by
- using an existing value numbering implementation to identify the common
- subexpressions, eliminating them when possible.
- </p>
-</div>
-
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="globaldce">Dead Global Elimination</a>
</div>
<div class="doc_text">
<p>
- This pass performs global value numbering to eliminate fully redundant
- instructions. It also performs simple dead load elimination.
+ This pass performs global value numbering to eliminate fully and partially
+ redundant instructions. It also performs redundant load elimination.
</p>
</div>
-<!-------------------------------------------------------------------------- -->
-<div class="doc_subsection">
- <a name="gvnpre">Global Value Numbering/Partial Redundancy Elimination</a>
-</div>
-<div class="doc_text">
- <p>
- This pass performs a hybrid of global value numbering and partial redundancy
- elimination, known as GVN-PRE. It performs partial redundancy elimination on
- values, rather than lexical expressions, allowing a more comprehensive view
- the optimization. It replaces redundant values with uses of earlier
- occurences of the same value. While this is beneficial in that it eliminates
- unneeded computation, it also increases register pressure by creating large
- live ranges, and should be used with caution on platforms that are very
- sensitive to register pressure.
- </p>
-</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
the dependence on the exit value of the induction variable. If the only
purpose of the loop is to compute the exit value of some derived
expression, this transformation will make the loop dead.</li>
- </p>
+ </ol>
<p>
This transformation should be followed by strength reduction after all of the
</p>
</div>
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="jump-threading">Thread control through conditional blocks</a>
+</div>
+<div class="doc_text">
+ <p>
+ Jump threading tries to find distinct threads of control flow running through
+ a basic block. This pass looks at blocks that have multiple predecessors and
+ multiple successors. If one or more of the predecessors of the block can be
+ proven to always cause a jump to one of the successors, we forward the edge
+ from the predecessor to the successor by duplicating the contents of this
+ block.
+ </p>
+ <p>
+ An example of when this can occur is code like this:
+ </p>
+
+ <pre
+>if () { ...
+ X = 4;
+}
+if (X < 3) {</pre>
+
+ <p>
+ In this case, the unconditional branch at the end of the first if can be
+ revectored to the false side of the second if.
+ </p>
+</div>
+
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="lcssa">Loop-Closed SSA Form Pass</a>
variable.</li>
</ul>
</div>
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="loop-deletion">Dead Loop Deletion Pass</a>
+</div>
+<div class="doc_text">
+ <p>
+ This file implements the Dead Loop Deletion Pass. This pass is responsible
+ for eliminating loops with non-infinite computable trip counts that have no
+ side effects or volatile instructions, and do not contribute to the
+ computation of the function's return value.
+ </p>
+</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
</p>
</div>
-<!-------------------------------------------------------------------------- -->
-<div class="doc_subsection">
- <a name="lower-packed">lowers packed operations to operations on smaller packed datatypes</a>
-</div>
-<div class="doc_text">
- <p>
- Lowers operations on vector datatypes into operations on more primitive vector
- datatypes, and finally to scalar operations.
- </p>
-</div>
-
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="lowerallocs">Lower allocations from instructions to calls</a>
</p>
</div>
-<!-------------------------------------------------------------------------- -->
-<div class="doc_subsection">
- <a name="lowergc">Lower GC intrinsics, for GCless code generators</a>
-</div>
-<div class="doc_text">
- <p>
- This file implements lowering for the <tt>llvm.gc*</tt> intrinsics for targets
- that do not natively support them (which includes the C backend). Note that
- the code generated is not as efficient as it would be for targets that
- natively support the GC intrinsics, but it is useful for getting new targets
- up-and-running quickly.
- </p>
-
- <p>
- This pass implements the code transformation described in this paper:
- </p>
-
- <blockquote><p>
- "Accurate Garbage Collection in an Uncooperative Environment"
- Fergus Henderson, ISMM, 2002
- </p></blockquote>
-</div>
-
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="lowerinvoke">Lower invoke and unwind, for unwindless code generators</a>
</p>
</div>
-<!-------------------------------------------------------------------------- -->
-<div class="doc_subsection">
- <a name="lowerselect">Lower select instructions to branches</a>
-</div>
-<div class="doc_text">
- <p>
- Lowers select instructions into conditional branches for targets that do not
- have conditional moves or that have not implemented the select instruction
- yet.
- </p>
-
- <p>
- Note that this pass could be improved. In particular it turns every select
- instruction into a new conditional branch, even though some common cases have
- select instructions on the same predicate next to each other. It would be
- better to use the same branch for the whole group of selects.
- </p>
-</div>
-
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="lowersetjmp">Lower Set Jump</a>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="mergereturn">Unify function exit nodes</a>
+ <a name="memcpyopt">Optimize use of memcpy and friend</a>
</div>
<div class="doc_text">
<p>
- Ensure that functions have at most one <tt>ret</tt> instruction in them.
- Additionally, it keeps track of which node is the new exit node of the CFG.
+ This pass performs various transformations related to eliminating memcpy
+ calls, or transforming sets of stores into memset's.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="predsimplify">Predicate Simplifier</a>
+ <a name="mergereturn">Unify function exit nodes</a>
</div>
<div class="doc_text">
<p>
- Path-sensitive optimizer. In a branch where <tt>x == y</tt>, replace uses of
- <tt>x</tt> with <tt>y</tt>. Permits further optimization, such as the
- elimination of the unreachable call:
+ Ensure that functions have at most one <tt>ret</tt> instruction in them.
+ Additionally, it keeps track of which node is the new exit node of the CFG.
</p>
-
-<blockquote><pre
->void test(int *p, int *q)
-{
- if (p != q)
- return;
-
- if (*p != *q)
- foo(); // unreachable
-}</pre></blockquote>
</div>
<!-------------------------------------------------------------------------- -->
</p>
</div>
-<!-------------------------------------------------------------------------- -->
-<div class="doc_subsection">
- <a name="raiseallocs">Raise allocations from calls to instructions</a>
-</div>
-<div class="doc_text">
- <p>
- Converts <tt>@malloc</tt> and <tt>@free</tt> calls to <tt>malloc</tt> and
- <tt>free</tt> instructions.
- </p>
-</div>
-
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="reassociate">Reassociate expressions</a>
<p>
This file demotes all registers to memory references. It is intented to be
the inverse of <a href="#mem2reg"><tt>-mem2reg</tt></a>. By converting to
- <tt>load</tt> instructions, the only values live accross basic blocks are
+ <tt>load</tt> instructions, the only values live across basic blocks are
<tt>alloca</tt> instructions and <tt>load</tt> instructions before
<tt>phi</tt> nodes. It is intended that this should make CFG hacking much
easier. To make later hacking easier, the entry block is split into two, such
</p>
</div>
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="strip-dead-prototypes">Remove unused function declarations</a>
+</div>
+<div class="doc_text">
+ <p>
+ This pass loops over all of the functions in the input module, looking for
+ dead declarations and removes them. Dead declarations are declarations of
+ functions for which no implementation is available (i.e., declarations for
+ unused library functions).
+ </p>
+</div>
+
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="sretpromotion">Promote sret arguments</a>
+</div>
+<div class="doc_text">
+ <p>
+ This pass finds functions that return a struct (using a pointer to the struct
+ as the first argument of the function, marked with the '<tt>sret</tt>' attribute) and
+ replaces them with a new function that simply returns each of the elements of
+ that struct (using multiple return values).
+ </p>
+
+ <p>
+ This pass works under a number of conditions:
+ </p>
+
+ <ul>
+ <li>The returned struct must not contain other structs</li>
+ <li>The returned struct must only be used to load values from</li>
+ <li>The placeholder struct passed in is the result of an <tt>alloca</tt></li>
+ </ul>
+</div>
+
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="tailcallelim">Tail Call Elimination</a>
<a name="deadarghaX0r">Dead Argument Hacking (BUGPOINT USE ONLY; DO NOT USE)</a>
</div>
<div class="doc_text">
- <p>Yet to be written.</p>
+ <p>
+ Same as dead argument elimination, but deletes arguments to functions which
+ are external. This is only for use by <a
+ href="Bugpoint.html">bugpoint</a>.</p>
</div>
<!-------------------------------------------------------------------------- -->
<a name="extract-blocks">Extract Basic Blocks From Module (for bugpoint use)</a>
</div>
<div class="doc_text">
- <p>Yet to be written.</p>
+ <p>
+ This pass is used by bugpoint to extract all blocks from the module into their
+ own functions.</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
- <a name="emitbitcode">Bitcode Writer</a>
+ <a name="preverify">Preliminary module verification</a>
</div>
<div class="doc_text">
- <p>Yet to be written.</p>
+ <p>
+ Ensures that the module is in the form required by the <a
+ href="#verifier">Module Verifier</a> pass.
+ </p>
+
+ <p>
+ Running the verifier runs this pass automatically, so there should be no need
+ to use it directly.
+ </p>
</div>
<!-------------------------------------------------------------------------- -->
<a name="verify">Module Verifier</a>
</div>
<div class="doc_text">
- <p>Yet to be written.</p>
+ <p>
+ Verifies an LLVM IR code. This is useful to run after an optimization which is
+ undergoing testing. Note that <tt>llvm-as</tt> verifies its input before
+ emitting bitcode, and also that malformed bitcode is likely to make LLVM
+ crash. All language front-ends are therefore encouraged to verify their output
+ before performing optimizing transformations.
+ </p>
+
+ <ul>
+ <li>Both of a binary operator's parameters are of the same type.</li>
+ <li>Verify that the indices of mem access instructions match other
+ operands.</li>
+ <li>Verify that arithmetic and other things are only performed on
+ first-class types. Verify that shifts and logicals only happen on
+ integrals f.e.</li>
+ <li>All of the constants in a switch statement are of the correct type.</li>
+ <li>The code is in valid SSA form.</li>
+ <li>It is illegal to put a label into any other type (like a structure) or
+ to return one.</li>
+ <li>Only phi nodes can be self referential: <tt>%x = add i32 %x, %x</tt> is
+ invalid.</li>
+ <li>PHI nodes must have an entry for each predecessor, with no extras.</li>
+ <li>PHI nodes must be the first thing in a basic block, all grouped
+ together.</li>
+ <li>PHI nodes must have at least one entry.</li>
+ <li>All basic blocks should only end with terminator insts, not contain
+ them.</li>
+ <li>The entry node to a function must not have predecessors.</li>
+ <li>All Instructions must be embedded into a basic block.</li>
+ <li>Functions cannot take a void-typed parameter.</li>
+ <li>Verify that a function's argument list agrees with its declared
+ type.</li>
+ <li>It is illegal to specify a name for a void value.</li>
+ <li>It is illegal to have a internal global value with no initializer.</li>
+ <li>It is illegal to have a ret instruction that returns a value that does
+ not agree with the function return value type.</li>
+ <li>Function call argument types match the function prototype.</li>
+ <li>All other things that are tested by asserts spread about the code.</li>
+ </ul>
+
+ <p>
+ Note that this does not provide full security verification (like Java), but
+ instead just tries to ensure that code is well-formed.
+ </p>
</div>
<!-------------------------------------------------------------------------- -->
<a name="view-cfg">View CFG of function</a>
</div>
<div class="doc_text">
- <p>Yet to be written.</p>
+ <p>
+ Displays the control flow graph using the GraphViz tool.
+ </p>
</div>
<!-------------------------------------------------------------------------- -->
<a name="view-cfg-only">View CFG of function (with no function bodies)</a>
</div>
<div class="doc_text">
- <p>Yet to be written.</p>
+ <p>
+ Displays the control flow graph using the GraphViz tool, but omitting function
+ bodies.
+ </p>
+</div>
+
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="view-dom">View dominator tree of function</a>
+</div>
+<div class="doc_text">
+ <p>
+ Displays the dominator tree using the GraphViz tool.
+ </p>
+</div>
+
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="view-dom-only">View dominator tree of function (with no function
+ bodies)
+ </a>
+</div>
+<div class="doc_text">
+ <p>
+ Displays the dominator tree using the GraphViz tool, but omitting function
+ bodies.
+ </p>
+</div>
+
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="view-postdom">View post dominator tree of function</a>
+</div>
+<div class="doc_text">
+ <p>
+ Displays the post dominator tree using the GraphViz tool.
+ </p>
+</div>
+
+<!-------------------------------------------------------------------------- -->
+<div class="doc_subsection">
+ <a name="view-postdom-only">View post dominator tree of function (with no
+ function bodies)
+ </a>
+</div>
+<div class="doc_text">
+ <p>
+ Displays the post dominator tree using the GraphViz tool, but omitting
+ function bodies.
+ </p>
</div>
<!-- *********************************************************************** -->
<hr>
<address>
<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
- src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
+ src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
<a href="http://validator.w3.org/check/referer"><img
- src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
+ src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
<a href="mailto:rspencer@x10sys.com">Reid Spencer</a><br>
<a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
projects / oota-llvm.git / blobdiff