In the LLVM IR module function annotations are stored in one big global array of strings. Traverse this array and parse the data into a format more useful for future passes. A map between Functions * and a list of annotations is exposed.
Signed-off-by: Anton Johansson <a...@rev.ng> --- .../include/FunctionAnnotation.h | 54 ++++++++++++ .../helper-to-tcg/include/PrepareForOptPass.h | 7 +- .../PrepareForOptPass/PrepareForOptPass.cpp | 87 +++++++++++++++++++ .../helper-to-tcg/pipeline/Pipeline.cpp | 3 +- 4 files changed, 149 insertions(+), 2 deletions(-) create mode 100644 subprojects/helper-to-tcg/include/FunctionAnnotation.h diff --git a/subprojects/helper-to-tcg/include/FunctionAnnotation.h b/subprojects/helper-to-tcg/include/FunctionAnnotation.h new file mode 100644 index 0000000000..b562f7c892 --- /dev/null +++ b/subprojects/helper-to-tcg/include/FunctionAnnotation.h @@ -0,0 +1,54 @@ +// +// Copyright(c) 2024 rev.ng Labs Srl. All Rights Reserved. +// +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 2 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program; if not, see <http://www.gnu.org/licenses/>. +// + +#pragma once + +#include <llvm/ADT/DenseMap.h> +#include <llvm/ADT/SmallVector.h> +#include <stdint.h> + +namespace llvm +{ +class Function; +} + +// Different kind of function annotations which control the behaviour +// of helper-to-tcg. +enum class AnnotationKind : uint8_t { + // Function should be translated + HelperToTcg, + // Declares a list of arguments as immediates + Immediate, + // Declares a list of arguments as vectors, represented by offsets into + // the CPU state + PtrToOffset, +}; + +// Annotation data which may be attached to a function +struct Annotation { + // Indices of function arguments the annotation applies to, only + // used for AnnotationKind::[Immediate|PtrToOffset]. + llvm::SmallVector<uint8_t, 4> ArgIndices; + AnnotationKind Kind; +}; + +// Map from Function * to a list of struct Annotation. std::map is used here +// which allocates for each mapped pair due to the value being large +// (at least 48*3 bits). If ArgIndices were to be stored out-of-band this could +// be reduced, and DenseMap would be more appropriate. +using AnnotationVectorTy = llvm::SmallVector<Annotation, 3>; +using AnnotationMapTy = llvm::DenseMap<llvm::Function *, AnnotationVectorTy>; diff --git a/subprojects/helper-to-tcg/include/PrepareForOptPass.h b/subprojects/helper-to-tcg/include/PrepareForOptPass.h index d74618613f..5f9c059b97 100644 --- a/subprojects/helper-to-tcg/include/PrepareForOptPass.h +++ b/subprojects/helper-to-tcg/include/PrepareForOptPass.h @@ -17,6 +17,7 @@ #pragma once +#include "FunctionAnnotation.h" #include <llvm/IR/PassManager.h> // @@ -27,8 +28,12 @@ // class PrepareForOptPass : public llvm::PassInfoMixin<PrepareForOptPass> { + AnnotationMapTy &ResultAnnotations; public: - PrepareForOptPass() {} + PrepareForOptPass(AnnotationMapTy &ResultAnnotations) + : ResultAnnotations(ResultAnnotations) + { + } llvm::PreservedAnalyses run(llvm::Module &M, llvm::ModuleAnalysisManager &MAM); }; diff --git a/subprojects/helper-to-tcg/passes/PrepareForOptPass/PrepareForOptPass.cpp b/subprojects/helper-to-tcg/passes/PrepareForOptPass/PrepareForOptPass.cpp index 0a018494fe..9f1d4df102 100644 --- a/subprojects/helper-to-tcg/passes/PrepareForOptPass/PrepareForOptPass.cpp +++ b/subprojects/helper-to-tcg/passes/PrepareForOptPass/PrepareForOptPass.cpp @@ -16,10 +16,97 @@ // #include <PrepareForOptPass.h> +#include <Error.h> + +#include <llvm/IR/Constants.h> +#include <llvm/IR/Function.h> +#include <llvm/IR/Instruction.h> +#include <llvm/IR/Module.h> using namespace llvm; +static Expected<Annotation> parseAnnotationStr(StringRef Str, + uint32_t num_function_args) +{ + Annotation Ann; + + Str = Str.trim(); + + if (Str.consume_front("helper-to-tcg")) { + Ann.Kind = AnnotationKind::HelperToTcg; + // Early return, no additional info to parse from annotation string + return Ann; + } else if (Str.consume_front("immediate")) { + Ann.Kind = AnnotationKind::Immediate; + } else if (Str.consume_front("ptr-to-offset")) { + Ann.Kind = AnnotationKind::PtrToOffset; + } else { + return mkError("Unknown annotation"); + } + + // Parse comma separated list of argument indices + + if (!Str.consume_front(":")) { + return mkError("Expected \":\""); + } + + Str = Str.ltrim(' '); + do { + Str = Str.ltrim(' '); + uint32_t i = 0; + Str.consumeInteger(10, i); + if (i >= num_function_args) { + return mkError("Annotation has out of bounds argument index"); + } + Ann.ArgIndices.push_back(i); + } while (Str.consume_front(",")); + + return Ann; +} + +static void collectAnnotations(Module &M, AnnotationMapTy &ResultAnnotations) +{ + // cast over dyn_cast is being used here to + // assert that the structure of + // + // llvm.global.annotation + // + // is what we expect. + + GlobalVariable *GA = M.getGlobalVariable("llvm.global.annotations"); + if (!GA) { + return; + } + + // Get the metadata which is stored in the first op + auto *CA = cast<ConstantArray>(GA->getOperand(0)); + // Loop over metadata + for (Value *CAOp : CA->operands()) { + auto *Struct = cast<ConstantStruct>(CAOp); + assert(Struct->getNumOperands() >= 2); + Constant *UseOfF = Struct->getOperand(0); + if (isa<UndefValue>(UseOfF)) { + continue; + } + auto *F = cast<Function>(UseOfF->getOperand(0)); + auto *AnnVar = + cast<GlobalVariable>(Struct->getOperand(1)->getOperand(0)); + auto *AnnData = cast<ConstantDataArray>(AnnVar->getOperand(0)); + + StringRef AnnStr = AnnData->getAsString(); + AnnStr = AnnStr.substr(0, AnnStr.size() - 1); + Expected<Annotation> Ann = parseAnnotationStr(AnnStr, F->arg_size()); + if (!Ann) { + dbgs() << "Failed to parse annotation: \"" << Ann.takeError() + << "\" for function " << F->getName() << "\n"; + continue; + } + ResultAnnotations[F].push_back(*Ann); + } +} + PreservedAnalyses PrepareForOptPass::run(Module &M, ModuleAnalysisManager &MAM) { + collectAnnotations(M, ResultAnnotations); return PreservedAnalyses::none(); } diff --git a/subprojects/helper-to-tcg/pipeline/Pipeline.cpp b/subprojects/helper-to-tcg/pipeline/Pipeline.cpp index fad335f4a9..3b9493bc73 100644 --- a/subprojects/helper-to-tcg/pipeline/Pipeline.cpp +++ b/subprojects/helper-to-tcg/pipeline/Pipeline.cpp @@ -174,7 +174,8 @@ int main(int argc, char **argv) MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM))); } - MPM.addPass(PrepareForOptPass()); + AnnotationMapTy Annotations; + MPM.addPass(PrepareForOptPass(Annotations)); { FunctionPassManager FPM; -- 2.45.2
