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| -rw-r--r-- | llvm/docs/WritingAnLLVMPass.html | 293 |
1 files changed, 216 insertions, 77 deletions
diff --git a/llvm/docs/WritingAnLLVMPass.html b/llvm/docs/WritingAnLLVMPass.html index 0ca54994f51..71dc4926ac3 100644 --- a/llvm/docs/WritingAnLLVMPass.html +++ b/llvm/docs/WritingAnLLVMPass.html @@ -83,6 +83,11 @@ <ul> <li><a href="#releaseMemory">The <tt>releaseMemory</tt> method</a></li> </ul></li> + <li><a href="#registering">Registering dynamically loaded passes</a> + <ul> + <li><a href="#registering_existing">Using existing registries</a></li> + <li><a href="#registering_new">Creating new registries</a></li> + </ul></li> <li><a href="#debughints">Using GDB with dynamically loaded passes</a> <ul> <li><a href="#breakpoint">Setting a breakpoint in your pass</a></li> @@ -97,7 +102,8 @@ </ol> <div class="doc_author"> - <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></p> + <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>, + <a href="mailto:jlaskey@apple.com">Jim Laskey</a></p> </div> <!-- *********************************************************************** --> @@ -163,7 +169,7 @@ source tree in the <tt>lib/Transforms/Hello</tt> directory.</p> copy the following into <tt>Makefile</tt>:</p> <hr/> -<pre> +<div class="doc_code"><pre> # Makefile for hello pass # Path to top level of LLVM heirarchy @@ -181,7 +187,7 @@ LOADABLE_MODULE = 1 # Include the makefile implementation stuff include $(LEVEL)/Makefile.common -</pre> +</pre></div> <p>This makefile specifies that all of the <tt>.cpp</tt> files in the current directory are to be compiled and linked together into a @@ -205,10 +211,10 @@ the pass itself.</p> <p>Now that we have a way to compile our new pass, we just have to write it. Start out with:</p> -<pre> +<div class="doc_code"><pre> <b>#include</b> "<a href="http://llvm.org/doxygen/Pass_8h-source.html">llvm/Pass.h</a>" <b>#include</b> "<a href="http://llvm.org/doxygen/Function_8h-source.html">llvm/Function.h</a>" -</pre> +</pre></div> <p>Which are needed because we are writing a <tt><a href="http://llvm.org/doxygen/classllvm_1_1Pass.html">Pass</a></tt>, and @@ -216,18 +222,18 @@ we are operating on <tt><a href="http://llvm.org/doxygen/classllvm_1_1Function.html">Function</a></tt>'s.</p> <p>Next we have:</p> -<pre> +<div class="doc_code"><pre> <b>using namespace llvm;</b> -</pre> +</pre></div> <p>... which is required because the functions from the include files live in the llvm namespace. </p> <p>Next we have:</p> -<pre> +<div class="doc_code"><pre> <b>namespace</b> { -</pre> +</pre></div> <p>... which starts out an anonymous namespace. Anonymous namespaces are to C++ what the "<tt>static</tt>" keyword is to C (at global scope). It makes the @@ -237,9 +243,9 @@ information.</p> <p>Next, we declare our pass itself:</p> -<pre> +<div class="doc_code"><pre> <b>struct</b> Hello : <b>public</b> <a href="#FunctionPass">FunctionPass</a> { -</pre><p> +</pre></div><p> <p>This declares a "<tt>Hello</tt>" class that is a subclass of <tt><a href="http://llvm.org/doxygen/classllvm_1_1FunctionPass.html">FunctionPass</a></tt>. @@ -248,13 +254,13 @@ href="#passtype">later</a>, but for now, know that <a href="#FunctionPass"><tt>FunctionPass</tt></a>'s operate a function at a time.</p> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> <a href="#runOnFunction">runOnFunction</a>(Function &F) { std::cerr << "<i>Hello: </i>" << F.getName() << "\n"; <b>return false</b>; } }; <i>// end of struct Hello</i> -</pre> +</pre></div> <p>We declare a "<a href="#runOnFunction"><tt>runOnFunction</tt></a>" method, which overloads an abstract virtual method inherited from <a @@ -262,10 +268,10 @@ href="#FunctionPass"><tt>FunctionPass</tt></a>. This is where we are supposed to do our thing, so we just print out our message with the name of each function.</p> -<pre> +<div class="doc_code"><pre> RegisterOpt<Hello> X("<i>hello</i>", "<i>Hello World Pass</i>"); } <i>// end of anonymous namespace</i> -</pre> +</pre></div> <p>Lastly, we register our class <tt>Hello</tt>, giving it a command line argument "<tt>hello</tt>", and a name "<tt>Hello World Pass</tt>". There are @@ -275,7 +281,7 @@ depending on what it is to be used for. For "optimizations" we use the <p>As a whole, the <tt>.cpp</tt> file looks like:</p> -<pre> +<div class="doc_code"><pre> <b>#include</b> "<a href="http://llvm.org/doxygen/Pass_8h-source.html">llvm/Pass.h</a>" <b>#include</b> "<a href="http://llvm.org/doxygen/Function_8h-source.html">llvm/Function.h</a>" @@ -291,7 +297,7 @@ depending on what it is to be used for. For "optimizations" we use the RegisterOpt<Hello> X("<i>hello</i>", "<i>Hello World Pass</i>"); } -</pre> +</pre></div> <p>Now that it's all together, compile the file with a simple "<tt>gmake</tt>" command in the local directory and you should get a new @@ -320,12 +326,12 @@ LLVM. We can now run the bytecode file (<tt>hello.bc</tt>) for the program through our transformation like this (or course, any bytecode file will work):</p> -<pre> +<div class="doc_code"><pre> $ opt -load ../../../Debug/lib/Hello.so -hello < hello.bc > /dev/null Hello: __main Hello: puts Hello: main -</pre> +</pre></div> <p>The '<tt>-load</tt>' option specifies that '<tt>opt</tt>' should load your pass as a shared object, which makes '<tt>-hello</tt>' a valid command line @@ -337,7 +343,7 @@ interesting way, we just throw away the result of <tt>opt</tt> (sending it to <p>To see what happened to the other string you registered, try running <tt>opt</tt> with the <tt>--help</tt> option:</p> -<pre> +<div class="doc_code"><pre> $ opt -load ../../../Debug/lib/Hello.so --help OVERVIEW: llvm .bc -> .bc modular optimizer @@ -354,7 +360,7 @@ OPTIONS: -inline - Function Integration/Inlining -instcombine - Combine redundant instructions ... -</pre> +</pre></div> <p>The pass name get added as the information string for your pass, giving some documentation to users of <tt>opt</tt>. Now that you have a working pass, you @@ -365,7 +371,7 @@ line option (<tt>--time-passes</tt>) that allows you to get information about the execution time of your pass along with the other passes you queue up. For example:</p> -<pre> +<div class="doc_code"><pre> $ opt -load ../../../Debug/lib/Hello.so -hello -time-passes < hello.bc > /dev/null Hello: __main Hello: puts @@ -381,7 +387,7 @@ Hello: main 0.0000 ( 0.0%) 0.0000 ( 0.0%) 0.0000 ( 0.0%) 0.0013 ( 2.7%) Module Verifier <b> 0.0000 ( 0.0%) 0.0000 ( 0.0%) 0.0000 ( 0.0%) 0.0033 ( 6.9%) Hello World Pass</b> 0.0100 (100.0%) 0.0100 (100.0%) 0.0200 (100.0%) 0.0479 (100.0%) TOTAL -</pre> +</pre></div> <p>As you can see, our implementation above is pretty fast :). The additional passes listed are automatically inserted by the '<tt>opt</tt>' tool to verify @@ -467,9 +473,9 @@ following signature:</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> runOnModule(Module &M) = 0; -</pre> +</pre></div> <p>The <tt>runOnModule</tt> method performs the interesting work of the pass. It should return true if the module was modified by the transformation and @@ -535,9 +541,9 @@ false if they didn't.</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> doInitialization(Module &M); -</pre> +</pre></div> <p>The <tt>doIninitialize</tt> method is allowed to do most of the things that <tt>CallGraphSCCPass</tt>'s are not allowed to do. They can add and remove @@ -556,9 +562,9 @@ fast).</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> runOnSCC(const std::vector<CallGraphNode *> &SCCM) = 0; -</pre> +</pre></div> <p>The <tt>runOnSCC</tt> method performs the interesting work of the pass, and should return true if the module was modified by the transformation, false @@ -574,9 +580,9 @@ otherwise.</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> doFinalization(Module &M); -</pre> +</pre></div> <p>The <tt>doFinalization</tt> method is an infrequently used method that is called when the pass framework has finished calling <a @@ -625,9 +631,9 @@ should return true if they modified the program, or false if they didn't.</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> doInitialization(Module &M); -</pre> +</pre></div> <p>The <tt>doIninitialize</tt> method is allowed to do most of the things that <tt>FunctionPass</tt>'s are not allowed to do. They can add and remove @@ -653,9 +659,9 @@ free functions that it needs, adding prototypes to the module if necessary.</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> runOnFunction(Function &F) = 0; -</pre><p> +</pre></div><p> <p>The <tt>runOnFunction</tt> method must be implemented by your subclass to do the transformation or analysis work of your pass. As usual, a true value should @@ -671,9 +677,9 @@ be returned if the function is modified.</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> doFinalization(Module &M); -</pre> +</pre></div> <p>The <tt>doFinalization</tt> method is an infrequently used method that is called when the pass framework has finished calling <a @@ -719,9 +725,9 @@ href="#FunctionPass"><tt>FunctionPass</tt></a>'s have, but also have the followi <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> doInitialization(Function &F); -</pre> +</pre></div> <p>The <tt>doIninitialize</tt> method is allowed to do most of the things that <tt>BasicBlockPass</tt>'s are not allowed to do, but that @@ -740,9 +746,9 @@ fast).</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> runOnBasicBlock(BasicBlock &BB) = 0; -</pre> +</pre></div> <p>Override this function to do the work of the <tt>BasicBlockPass</tt>. This function is not allowed to inspect or modify basic blocks other than the @@ -759,9 +765,9 @@ if the basic block is modified.</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> doFinalization(Function &F); -</pre> +</pre></div> <p>The <tt>doFinalization</tt> method is an infrequently used method that is called when the pass framework has finished calling <a @@ -805,9 +811,9 @@ data)</li> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual bool</b> runOnMachineFunction(MachineFunction &MF) = 0; -</pre> +</pre></div> <p><tt>runOnMachineFunction</tt> can be considered the main entry point of a <tt>MachineFunctionPass</tt>; that is, you should override this method to do the @@ -877,9 +883,9 @@ should implement the virtual <tt>print</tt> method:</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual void</b> print(std::ostream &O, <b>const</b> Module *M) <b>const</b>; -</pre> +</pre></div> <p>The <tt>print</tt> method must be implemented by "analyses" in order to print a human readable version of the analysis results. This is useful for debugging @@ -927,9 +933,9 @@ having any prerequisite passes, and invalidating <b>all</b> other passes.</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual void</b> getAnalysisUsage(AnalysisUsage &Info) <b>const</b>; -</pre> +</pre></div> <p>By implementing the <tt>getAnalysisUsage</tt> method, the required and invalidated sets may be specified for your transformation. The implementation @@ -1008,24 +1014,24 @@ the fact that it hacks on the CFG. <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <i>// This is an example implementation from an analysis, which does not modify // the program at all, yet has a prerequisite.</i> <b>void</b> <a href="http://llvm.org/doxygen/classllvm_1_1PostDominanceFrontier.html">PostDominanceFrontier</a>::getAnalysisUsage(AnalysisUsage &AU) <b>const</b> { AU.setPreservesAll(); AU.addRequired<<a href="http://llvm.org/doxygen/classllvm_1_1PostDominatorTree.html">PostDominatorTree</a>>(); } -</pre> +</pre></div> <p>and:</p> -<pre> +<div class="doc_code"><pre> <i>// This example modifies the program, but does not modify the CFG</i> <b>void</b> <a href="http://llvm.org/doxygen/structLICM.html">LICM</a>::getAnalysisUsage(AnalysisUsage &AU) <b>const</b> { AU.setPreservesCFG(); AU.addRequired<<a href="http://llvm.org/doxygen/classllvm_1_1LoopInfo.html">LoopInfo</a>>(); } -</pre> +</pre></div> </div> @@ -1042,12 +1048,12 @@ required with the <a href="#getAnalysisUsage"><tt>getAnalysisUsage</tt></a> method. It takes a single template argument that specifies which pass class you want, and returns a reference to that pass. For example:</p> -<pre> +<div class="doc_code"><pre> bool LICM::runOnFunction(Function &F) { LoopInfo &LI = getAnalysis<LoopInfo>(); ... } -</pre> +</pre></div> <p>This method call returns a reference to the pass desired. You may get a runtime assertion failure if you attempt to get an analysis that you did not @@ -1062,13 +1068,13 @@ If your pass is capable of updating analyses if they exist (e.g., <tt>getAnalysisToUpdate</tt> method, which returns a pointer to the analysis if it is active. For example:</p> -<pre> +<div class="doc_code"><pre> ... if (DominatorSet *DS = getAnalysisToUpdate<DominatorSet>()) { <i>// A DominatorSet is active. This code will update it.</i> } ... -</pre> +</pre></div> </div> @@ -1163,14 +1169,14 @@ an analysis should be registered, with a human readable name provided for it. Unlike registration of passes, there is no command line argument to be specified for the Analysis Group Interface itself, because it is "abstract":</p> -<pre> +<div class="doc_code"><pre> <b>static</b> RegisterAnalysisGroup<<a href="http://llvm.org/doxygen/classllvm_1_1AliasAnalysis.html">AliasAnalysis</a>> A("<i>Alias Analysis</i>"); -</pre> +</pre></div> <p>Once the analysis is registered, passes can declare that they are valid implementations of the interface by using the following code:</p> -<pre> +<div class="doc_code"><pre> <b>namespace</b> { //<i> Analysis Group implementations <b>must</b> be registered normally...</i> RegisterOpt<FancyAA> @@ -1179,7 +1185,7 @@ implementations of the interface by using the following code:</p> //<i> Declare that we implement the AliasAnalysis interface</i> RegisterAnalysisGroup<<a href="http://llvm.org/doxygen/classllvm_1_1AliasAnalysis.html">AliasAnalysis</a>, FancyAA> C; } -</pre> +</pre></div> <p>This just shows a class <tt>FancyAA</tt> that is registered normally, then uses the <tt>RegisterAnalysisGroup</tt> template to "join" the <tt><a @@ -1188,7 +1194,7 @@ analysis group. Every implementation of an analysis group should join using this template. A single pass may join multiple different analysis groups with no problem.</p> -<pre> +<div class="doc_code"><pre> <b>namespace</b> { //<i> Analysis Group implementations <b>must</b> be registered normally...</i> RegisterOpt<<a href="http://llvm.org/doxygen/structBasicAliasAnalysis.html">BasicAliasAnalysis</a>> @@ -1197,7 +1203,7 @@ no problem.</p> //<i> Declare that we implement the AliasAnalysis interface</i> RegisterAnalysisGroup<<a href="http://llvm.org/doxygen/classllvm_1_1AliasAnalysis.html">AliasAnalysis</a>, <a href="http://llvm.org/doxygen/structBasicAliasAnalysis.html">BasicAliasAnalysis</a>, <b>true</b>> E; } -</pre> +</pre></div> <p>Here we show how the default implementation is specified (using the extra argument to the <tt>RegisterAnalysisGroup</tt> template). There must be exactly @@ -1290,7 +1296,7 @@ option, just type '<tt>opt --help-hidden</tt>').</p> how our <a href="#basiccode">Hello World</a> pass interacts with other passes. Lets try it out with the <tt>gcse</tt> and <tt>licm</tt> passes:</p> -<pre> +<div class="doc_code"><pre> $ opt -load ../../../Debug/lib/Hello.so -gcse -licm --debug-pass=Structure < hello.bc > /dev/null Module Pass Manager Function Pass Manager @@ -1308,7 +1314,7 @@ Module Pass Manager -- Module Verifier Bytecode Writer --Bytecode Writer -</pre> +</pre></div> <p>This output shows us when passes are constructed and when the analysis results are known to be dead (prefixed with '<tt>--</tt>'). Here we see that @@ -1327,7 +1333,7 @@ passes.</p> <p>Lets see how this changes when we run the <a href="#basiccode">Hello World</a> pass in between the two passes:</p> -<pre> +<div class="doc_code"><pre> $ opt -load ../../../Debug/lib/Hello.so -gcse -hello -licm --debug-pass=Structure < hello.bc > /dev/null Module Pass Manager Function Pass Manager @@ -1352,23 +1358,23 @@ Module Pass Manager Hello: __main Hello: puts Hello: main -</pre> +</pre></div> <p>Here we see that the <a href="#basiccode">Hello World</a> pass has killed the Dominator Set pass, even though it doesn't modify the code at all! To fix this, we need to add the following <a href="#getAnalysisUsage"><tt>getAnalysisUsage</tt></a> method to our pass:</p> -<pre> +<div class="doc_code"><pre> <i>// We don't modify the program, so we preserve all analyses</i> <b>virtual void</b> getAnalysisUsage(AnalysisUsage &AU) <b>const</b> { AU.setPreservesAll(); } -</pre> +</pre></div> <p>Now when we run our pass, we get this output:</p> -<pre> +<div class="doc_code"><pre> $ opt -load ../../../Debug/lib/Hello.so -gcse -hello -licm --debug-pass=Structure < hello.bc > /dev/null Pass Arguments: -gcse -hello -licm Module Pass Manager @@ -1392,7 +1398,7 @@ Module Pass Manager Hello: __main Hello: puts Hello: main -</pre> +</pre></div> <p>Which shows that we don't accidentally invalidate dominator information anymore, and therefore do not have to compute it twice.</p> @@ -1406,9 +1412,9 @@ anymore, and therefore do not have to compute it twice.</p> <div class="doc_text"> -<pre> +<div class="doc_code"><pre> <b>virtual void</b> releaseMemory(); -</pre> +</pre></div> <p>The <tt>PassManager</tt> automatically determines when to compute analysis results, and how long to keep them around for. Because the lifetime of the pass @@ -1427,6 +1433,139 @@ class, before the next call of <tt>run*</tt> in your pass.</p> <!-- *********************************************************************** --> <div class="doc_section"> + <a name="registering">Registering dynamically loaded passes</a> +</div> +<!-- *********************************************************************** --> + +<div class="doc_text"> + +<p><i>Size matters</i> when constructing production quality tools using llvm, +both for the purposes of distribution, and for regulating the resident code size +when running on the target system. Therefore, it becomes desirable to +selectively use some passes, while omitting others and maintain the flexibility +to change configurations later on. You want to be able to do all this, and, +provide feedback to the user. This is where pass registration comes into +play.</p> + +<p>The fundamental mechanisms for pass registration are the +<tt>MachinePassRegistry</tt> class and subclasses of +<tt>MachinePassRegistryNode</tt>.</p> + +<p>An instance of <tt>MachinePassRegistry</tt> is used to maintain a list of +<tt>MachinePassRegistryNode</tt> objects. This instance maintains the list and +communicates additions and deletions to the command line interface.</p> + +<p>An instance of <tt>MachinePassRegistryNode</tt> subclass is used to maintain +information provided about a particular pass. This information includes the +command line name, the command help string and the address of the function used +to create an instance of the pass. A global static constructor of one of these +instances <i>registers</i> with a corresponding <tt>MachinePassRegistry</tt>, +the static destructor <i>unregisters</i>. Thus a pass that is statically linked +in the tool will be registered at start up. A dynamically loaded pass will +register on load and unregister at unload.</p> + +</div> + +<!-- _______________________________________________________________________ --> +<div class="doc_subsection"> + <a name="registering_existing">Using existing registries</a> +</div> + +<div class="doc_text"> + +<p>There are predefined registries to track instruction scheduling +(<tt>RegisterScheduler</tt>) and register allocation (<tt>RegisterRegAlloc</tt>) +machine passes. Here we will describe how to <i>register</i> a register +allocator machine pass.</p> + +<p>Implement your register allocator machine pass. In your register allocator +.cpp file add the following include;</p> + +<div class="doc_code"><pre> + #include ""llvm/CodeGen/RegAllocRegistry.h"" +</pre></div> + +<p>Also in your register allocator .cpp file, define a creator function in the +form; </p> + +<div class="doc_code"><pre> + FunctionPass *createMyRegisterAllocator() { + return new MyRegisterAllocator(); + } +</pre></div> + +<p>Note that the signature of this function should match the type of +<tt>RegisterRegAlloc::FunctionPassCtor</tt>. In the same file add the +"installing" declaration, in the form;</p> + +<div class="doc_code"><pre> + static RegisterRegAlloc myRegAlloc("myregalloc", + " my register allocator help string", + createMyRegisterAllocator); +</pre></div> + +<p>Note the two spaces prior to the help string produces a tidy result on the +--help query.</p> + +<div class="doc_code"><pre> +$ llc --help + ... + -regalloc - Register allocator to use: (default = linearscan) + =linearscan - linear scan register allocator + =local - local register allocator + =simple - simple register allocator + =myregalloc - my register allocator help string + ... +</pre></div> + +<p>And that's it. The user is now free to use <tt>-regalloc=myregalloc</tt> as +an option. Registering instruction schedulers is similar except use the +<tt>RegisterRegAlloc</tt> class. Note that the +<tt>RegisterRegAlloc::FunctionPassCtor</tt> is significantly different from +<tt>RegisterRegAlloc::FunctionPassCtor</tt>.</p> + +<p>To force the load/linking of your register allocator into the llc/lli tools, +add your creator function's global declaration to "Passes.h" and add a "pseudo" +call line to <tt>llvm/Codegen/LinkAllCodegenComponents.h</tt>.</p> + +</div> + + +<!-- _______________________________________________________________________ --> +<div class="doc_subsection"> + <a name="registering_new">Creating new registries</a> +</div> + +<div class="doc_text"> + +<p>The easiest way to get started is to clone one of the existing registries; we +recommend <tt>llvm/CodeGen/RegAllocRegistry.h</tt>. The key things to modify +are the class name and the <tt>FunctionPassCtor</tt> type.</p> + +<p>Then you need to declare the registry. Example: if your pass registry is +<tt>RegisterMyPasses</tt> then define;</p> + +<div class="doc_code"><pre> +MachinePassRegistry RegisterMyPasses::Registry; +</pre></div> + +<p>And finally, declare the command line option for your passes. Example:</p> + +<div class="doc_code"><pre> + cl::opt<RegisterMyPasses::FunctionPassCtor, false, + RegisterPassParser<RegisterMyPasses> > + MyPassOpt("mypass", + cl::init(&createDefaultMyPass), + cl::desc("my pass option help")); +</pre></div> + +<p>Here the command option is "mypass", with createDefaultMyPass as the default +creator.</p> + +</div> + +<!-- *********************************************************************** --> +<div class="doc_section"> <a name="debughints">Using GDB with dynamically loaded passes</a> </div> <!-- *********************************************************************** --> @@ -1454,7 +1593,7 @@ on that.</p> <p>First thing you do is start <tt>gdb</tt> on the <tt>opt</tt> process:</p> -<pre> +<div class="doc_code"><pre> $ <b>gdb opt</b> GNU gdb 5.0 Copyright 2000 Free Software Foundation, Inc. @@ -1464,7 +1603,7 @@ Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "sparc-sun-solaris2.6"... (gdb) -</pre> +</pre></div> <p>Note that <tt>opt</tt> has a lot of debugging information in it, so it takes time to load. Be patient. Since we cannot set a breakpoint in our pass yet @@ -1474,7 +1613,7 @@ object. The most foolproof way of doing this is to set a breakpoint in <tt>PassManager::run</tt> and then run the process with the arguments you want:</p> -<pre> +<div class="doc_code"><pre> (gdb) <b>break PassManager::run</b> Breakpoint 1 at 0x2413bc: file Pass.cpp, line 70. (gdb) <b>run test.bc -load $(LLVMTOP)/llvm/Debug/lib/[libname].so -[passoption]</b> @@ -1482,7 +1621,7 @@ Starting program: opt test.bc -load $(LLVMTOP)/llvm/Debug/lib/[libname].so -[pas Breakpoint 1, PassManager::run (this=0xffbef174, M=@0x70b298) at Pass.cpp:70 70 bool PassManager::run(Module &M) { return PM->run(M); } (gdb) -</pre> +</pre></div> <p>Once the <tt>opt</tt> stops in the <tt>PassManager::run</tt> method you are now free to set breakpoints in your pass so that you can trace through execution |
