<html><head><base href="x-msg://65/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Feb 11, 2010, at 9:20 AM, Anton Lokhmotov wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div lang="EN-GB" link="blue" vlink="purple"><div class="Section1"><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">Dear Clang aficionados,<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">I’d like to adapt Clang to accept a C extension, perform a bit of analysis and then output LLVM IR. <o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">First, I learnt how to use Sema/ParseAST and CodeGen/ModuleBuilder in the 2.6 release. However, since ParseAST in not re-enterable I can’t do analysis and code generation at the same time. So I’d really appreciate if you could point me to the right way of doing this!</div></div></div></span></blockquote><div><br></div>CompilerInstance/CompilerInvocation are definitely the way to do this. You could also build your own FrontendAction that does both analysis and codegen in one shot.</div><div><br><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div lang="EN-GB" link="blue" vlink="purple"><div class="Section1"><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">Second, I’m looking to the development branch. I see some great looking API changes, such as introducing CompilerInstance and CompilerInvocation, and a bunch of FrontendActions. I was hoping to use FrontendActions for implementing my analysis and code gen, but no luck so far.<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">The minimal program<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">/// \file CompilerInstance.c<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">#include <clang/Frontend/FrontendActions.h><o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">int main()<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">{<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; "> clang::EmitLLVMOnlyAction emitLLVM;<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">}<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">results in:<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">lib/VMCore/Pass.cpp:228: void <unnamed>::PassRegistrar::RegisterPass(const llvm::PassInfo&): Assertion `Inserted && "Pass registered multiple times!"' failed.<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">In addition, by trial and error I figured out that I needed to link against many Clang and LLVM libraries, e.g.<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">g++ ./CompilerInstance.o -lclangFrontend -lclangSema -lclangDriver -lclangAnalysis -lclangChecker -lclangRewrite -lclangAST -lclangCodeGen -lclangLex -lclangBasic -lclangParse -lLLVMScalarOpts -lLLVMInstCombine -lLLVMSelectionDAG -lLLVMipo -lLLVMipa -lLTO -lLLVMTransformUtils -lLLVMBitWriter -lLLVMAnalysis -lLLVMCodeGen -lLLVMCore -lLLVMMC -lLLVMSupport -lLLVMSystem -lLLVMTarget -lm -ldl –lpthread<o:p></o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">I find it weird that in order to use a FrontendAction that only emits LLVM code I also need to link against so many optimisation libraries. </div></div></div></span></blockquote><div><br></div><div>When you're emitting LLVM IR, you naturally end up using LLVM's optimization infrastructure to handle that IR, so you need to link in that code.</div><br><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div lang="EN-GB" link="blue" vlink="purple"><div class="Section1"><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0.0001pt; margin-left: 0cm; font-size: 11pt; font-family: Calibri, sans-serif; ">Can I conclude from this experience that FrontendActions are not supposed to be used like this? (The same happens when I first initialise a CompilerInstance properly and then declare an EmitLLVMOnlyAction object.) Again, what would be the right way to do this?</div></div></div></span></blockquote><br></div><div>It seems like you're doing the right thing. You can use llvm-config to help you figure out exactly which libraries you need to link against to get the right back-end bits.</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>- Doug</div></body></html>