similar to: Assembly file compilation flow

Passing an assembly file to clang does not go through any CodeGen phases. It operates entirely in the MC layer. No MachineFunctions will be created. It just runs it through the MCAsmParser. Most of the setup for this is in clang's tools/driver/cc1as_main.cpp in the function ExecuteAssembler ~Craig On Thu, May 10, 2018 at 1:32 PM Soham Sinha via llvm-dev < llvm-dev at lists.llvm.org>

I think a key point to understand is the MCStreamer interface, which has two implementations: one for object-file generation, and one for .s file generation. CodeGen/AsmPrinter can attach to either of these implementations. MCAsmParser will generally attach to the object-file version of MCStreamer. --paulr From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Craig Topper via

It does, when the function has a body. When it doesn't, it ignores <https://godbolt.org/g/2BCvht>. The body might be provided later on in the toolchain via linking a library. Regards, Soham Sinha PhD Student, Department of Computer Science Boston University On Tue, Jun 26, 2018 at 10:25 AM Hans Wennborg <hans at chromium.org> wrote: > It works for me: > >

For the same reason GCC allowed the attribute. Even if I want to use/inline a function later on in the pipeline. Regards, Soham Sinha PhD Student, Department of Computer Science Boston University On Tue, Jun 26, 2018 at 8:30 AM mayuyu.io <admin at mayuyu.io> wrote: > Out of curiosity, how does an unused declaration affect the emitted object > file > > Zhang > > > 在

Hello, I want to add assembly instructions at certain points in a function. This is X86 specific. So I am working in the lib/Target/X86 folder. I create a `MachineFunctionPass` in that folder. I register it in the X86TargetMachine.cpp in addPreEmitPass(). I use BuildMI to insert my own assembly instructions in the MachineFunctionPass. This works and my assembly instructions are inserted at

One place to look might be in the MachineOutliner target hooks in X86InstrInfo and AArch64InstrInfo. The MachineOutliner runs extremely late in the pass pipeline so it might be a good place to look for some inspiration. Of course, because this is *extremely late* it might not do *exactly* what you need. (e.g, this is post-register allocation, post frame-lowering, etc.) - Jessica > On May 4,

clang doesn't seem to respect __attribute__((used)) in C functions. Even if I declare a function like the following: __attribute__((used)) void function(), then also it doesn't declare the function in its IR file if I don't use the function. Is there any other way to force the declaration of "unused" function declarations with clang. I have hacked in clang 6.0.0 in

Hello, How can I inline a function mentioned in other file? I have an inline function *foo* in C source file (a.c) which is not referenced in this file. I compile this file to a.ll (I notice that the compiled a.ll doesn't have *foo*'s definition, probably because it was inlined but not called anywhere) I have another C source file b.c with function *bar*; I compile this to b.ll I link

Hello Dean, I looked at the XRay Instrumentation. That's a nice engineering effort. I am sure you had your motivation to do this in CodeGen just like I wanted to do. I don't understand all of your code but I get the idea that you are adjusting the alignment with explicit bytes and no-op instructions. My problem is also very much related to yours where my stack pointer ($rsp) alignment

Hi Eli, I have tried that: static void registerMyPass(const PassManagerBuilder &, llvm::legacy::PassManagerBase &PM) { PM.add(new MyPass()); } static RegisterStandardPasses RegisterMyPass(PassManagerBuilder::EP_OptimizerLast, registerMyPass); It still couldn't find my pass. Regards, Soham Sinha PhD Student,

Hi Soham, “extern inline” keyword will help in this case, with this keyword compiler is forced to keeps the definition of the function and make it available for the external usage. Also it retains the “inlinehint” attribute on the function, with that lto inliner may make it inline. Best, Ashutosh From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Mehdi AMINI via llvm-dev

Hello, I have written a pass for the IR and I can run it with opt -load lib/LLVMMyPass.so -mypass -myarguments -S -o output.ll < output.bc I have registered my pass with the following code: static RegisterPass<MyPass> X("mypass", "MyPass Pass (with getAnalysisUsage implemented)"); How do I include the same pass in the clang driver. I tried running the pass: clang

On Tue, May 8, 2018 at 4:06 AM Soham Sinha <soham1 at bu.edu> wrote: > Hello Dean, > I looked at the XRay Instrumentation. That's a nice engineering effort. I am sure you had your motivation to do this in CodeGen just like I wanted to do. I don't understand all of your code but I get the idea that you are adjusting the alignment with explicit bytes and no-op instructions. My

Hi Soham, Are you intending to use the inline keyword in order to control the inlining optimization? The inline keyword is not doing this, it is changing the linkage type of the symbol and instruct the compiler to discard it if there is no call left, and also will instruct the linker to deduplicate. For instance if multiple file include a header that defines an inline function, this function

On Sun, May 6, 2018 at 7:26 AM Soham Sinha via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Hello, > I want to add assembly instructions at certain points in a function. This is X86 specific. So I am working in the lib/Target/X86 folder. I create a `MachineFunctionPass` in that folder. I register it in the X86TargetMachine.cpp in addPreEmitPass(). I use BuildMI to insert my own

> > Date: Mon, 14 May 2018 14:26:13 -0400 > From: Kenneth Adam Miller via llvm-dev <llvm-dev at lists.llvm.org> > To: llvm-dev <llvm-dev at lists.llvm.org> > Subject: [llvm-dev] Andresen Algorithm > Message-ID: > <CAK7rcp_yXA79UuLvcD6LPMQBvi9tTpOGAcuWZ > Ux1tFKTyvuh2Q at mail.gmail.com> > Content-Type: text/plain; charset="utf-8" >

Actually I figured out that it is: opt -cfl-anders-aa *.ll But now I noticed that I need the graph that it computes, and it doesn't seem to emit that. On Wed, May 16, 2018 at 5:19 PM, Kenneth Adam Miller < kennethadammiller at gmail.com> wrote: > Is there a particular way to run a specific alias analysis that is already > implemented on a .ll file produced by clang -S

Hi Dean, I looked at XRay. I also thought on the similar line to add assembly instructions as auxiliary template code and jump on to there. However, that may still dis-align the stack. I have to think about it. But your XRay code does give me the courage to think about this seriously. Thank you for your help. I also figured out that we can access certain CodeGen's feature right from the IR

Is there a particular way to run a specific alias analysis that is already implemented on a .ll file produced by clang -S -emit-llvm? On Mon, May 14, 2018 at 7:36 PM, Soham Sinha via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Date: Mon, 14 May 2018 14:26:13 -0400 >> From: Kenneth Adam Miller via llvm-dev <llvm-dev at lists.llvm.org> >> To: llvm-dev <llvm-dev at

Usually you need to add the -analyze option, to dump the analysis results. On Wed, May 16, 2018 at 9:09 PM, Kenneth Adam Miller via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Actually I figured out that it is: > > opt -cfl-anders-aa *.ll > > But now I noticed that I need the graph that it computes, and it doesn't > seem to emit that. > > On Wed, May 16,