search for: lowerconstant

...of global variables, at least for the trivial case. The trivial case is if TargetLowering::isNoopAddrSpaceCast(SrcAS, DestAS) returns true. In this case the MCExpr for the addrspacecast is the MCExpr of its first operand. It seems hard to obtain an instance of TargetLowering in AsmPrinter::lowerConstant(). Other methods in this class obtain it by calling `MF->getSubtarget().getTargetLowering()`. However, because MF is nullptr when lowering initializers of global variables, it won't work. My impression is that this is not possible because every function has its own TargetLowering inst...

...d.zip.s was ~>190Mb when this crush occurred. > > > > How this can be corrected? > > Attached patch should fix the issue. The unreachable condition was > caused by a constant expression involving an inttoptr from i32. This > results in a zext to 64 bits, but apparently LowerConstant in > AsmPrinter doesn't handle constant expressions involving zext. Aren't > zext constant expressions supported by LLVM? > > - Allan > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs....

...st solution, but there were some problems and the fact that this is my first attempt to change LLVM. My original assumption was that, changing MCExpr to accept relocation information, we could propagate that down later to whatever gets written from it. To change that, one needs to overwrite the LowerConstant function in AsmPrinter, but that's a static function that rely on other static functions in the same file. Also, ARMMCInstLower (my first guess) seems to have not being used to generate anything. I know that MC is radically changing the area as we speak, so I also didn't want to spend t...

...or always trying to do pointer arithmetic using i32 instead of the target's pointer size, which is what my patch addressed. As for whether there is a bug in LLVM, I'm not sure. I've played around with it some more, and it looks like zext expressions get constant folded before reaching LowerConstant. The only way I've triggered the unreachable condition is to make a pointer->i32->pointer constant expression on a 64bit machine, similar to what vmkit was doing. Attached is a test case. The commented out expressions don't trigger the unreachable condition, nor does a simple zext...

...c (93Mb), > glibj-optimized.zip.s  was ~>190Mb when this crush occurred. > > How this can be corrected? Attached patch should fix the issue. The unreachable condition was caused by a constant expression involving an inttoptr from i32. This results in a zext to 64 bits, but apparently LowerConstant in AsmPrinter doesn't handle constant expressions involving zext. Aren't zext constant expressions supported by LLVM? - Allan -------------- next part -------------- A non-text attachment was scrubbed... Name: libvmjc.diff Type: text/x-patch Size: 909 bytes Desc: not available URL: <h...

Hi, Trying to build AOT version of vmkit java, building for that classpath glibj.zip: $ cd vmkit/tools/vmjc/libvmjc $ make ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1 REQUIRES_FRAME_POINTER=1 has eventually, after 50 minutes, brought: <<< llvm[0]: Compiling glibj.zip to llvm llvm[0]: Optimizing glibj.zip llvm[0]: Compiling glibj.zip.bc to native UNREACHABLE executed! 0 llc

...ion, but there were some problems and the fact that this is my first attempt to change LLVM. > > My original assumption was that, changing MCExpr to accept relocation information, we could propagate that down later to whatever gets written from it. To change that, one needs to overwrite the LowerConstant function in AsmPrinter, but that’s a static function that rely on other static functions in the same file. Also, ARMMCInstLower (my first guess) seems to have not being used to generate anything. > > I know that MC is radically changing the area as we speak, so I also didn’t want to spend t...

Hi, I was wondering how exactly LLVM handles the ConstantExpr, specifically GEP ConstantExpr, in code generation. From what I'm reading, translating these Constant Expressions into Instructions can slow the code, so I'd like to be able to handle ConstantExpr in the same way that LLVM code generation does. Thanks, Brandon

...there were some problems and the fact that this is my first attempt to change LLVM. >> >> My original assumption was that, changing MCExpr to accept relocation information, we could propagate that down later to whatever gets written from it. To change that, one needs to overwrite the LowerConstant function in AsmPrinter, but that’s a static function that rely on other static functions in the same file. Also, ARMMCInstLower (my first guess) seems to have not being used to generate anything. >> >> I know that MC is radically changing the area as we speak, so I also didn’t want to...

...getelementptr (i32, i32* bitcast ([3 x > i32]* @w > > to i32*), i32 1) > > > > This way, you save yourself from needing to worry about manipulating > addends > > in the backend, the linker will take care of it for you. > > That's no worry at all, AsmPrinter::lowerConstant evaluates both > constant expressions to MCExpr: w + 4. > But you still need to worry about how "w + 4" is represented in the object file. > Do you suggest we use this to limit "reloc" to accepting only > GlobalValue as the second argument instead of an arbitrary...

...> to i32*), i32 1) > >> > > >> > This way, you save yourself from needing to worry about manipulating > >> > addends > >> > in the backend, the linker will take care of it for you. > >> > >> That's no worry at all, AsmPrinter::lowerConstant evaluates both > >> constant expressions to MCExpr: w + 4. > > > > > > But you still need to worry about how "w + 4" is represented in the > object > > file. > > It's a relocation with target "w" and addend "4". > Someo...

On Fri, Oct 7, 2016 at 12:20 PM, Evgenii Stepanov <eugeni.stepanov at gmail.com > wrote: > I've tried implementing some of the alternatives mentioned in this > thread, and so far I like this syntax the most: > > i32 reloc (29, void ()* @f, 3925868544) > ; 29 = 0x1d = R_ARM_JUMP24 > ; 3925868544 = 0xea000000 > > Note the zeroes in the relocated data instead of

...llvm::Mangler::ManglerPrefixTy)", referenced from: llvm::AsmPrinter::GetExternalSymbolSymbol(llvm::StringRef) constin libLLVMAsmPrinter.a(AsmPrinter.cpp.o) "llvm::TargetData::getIndexedOffset(llvm::Type const*, llvm::Value* const*, unsigned int) const", referenced from: LowerConstant(llvm::Constant const*, llvm::AsmPrinter&)in libLLVMAsmPrinter.a(AsmPrinter.cpp.o) SymbolicallyEvaluateGEP(llvm::Constant* const*, unsigned int, llvm::Type const*, llvm::TargetData const*)in libLLVMAnalysis.a(ConstantFolding.cpp.o) SymbolicallyEvaluateGEP(llvm::Constant* const*, unsi...