Files
clang-p2996/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp
Teresa Johnson 9c27b59cec Change TargetLibraryInfo analysis passes to always require Function
Summary:
This is the first change to enable the TLI to be built per-function so
that -fno-builtin* handling can be migrated to use function attributes.
See discussion on D61634 for background. This is an enabler for fixing
handling of these options for LTO, for example.

This change should not affect behavior, as the provided function is not
yet used to build a specifically per-function TLI, but rather enables
that migration.

Most of the changes were very mechanical, e.g. passing a Function to the
legacy analysis pass's getTLI interface, or in Module level cases,
adding a callback. This is similar to the way the per-function TTI
analysis works.

There was one place where we were looking for builtins but not in the
context of a specific function. See FindCXAAtExit in
lib/Transforms/IPO/GlobalOpt.cpp. I'm somewhat concerned my workaround
could provide the wrong behavior in some corner cases. Suggestions
welcome.

Reviewers: chandlerc, hfinkel

Subscribers: arsenm, dschuff, jvesely, nhaehnle, mehdi_amini, javed.absar, sbc100, jgravelle-google, eraman, aheejin, steven_wu, george.burgess.iv, dexonsmith, jfb, asbirlea, gchatelet, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66428

llvm-svn: 371284
2019-09-07 03:09:36 +00:00

85 lines
2.9 KiB
C++

//===- InferFunctionAttrs.cpp - Infer implicit function attributes --------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO/InferFunctionAttrs.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
using namespace llvm;
#define DEBUG_TYPE "inferattrs"
static bool inferAllPrototypeAttributes(
Module &M, function_ref<TargetLibraryInfo &(Function &)> GetTLI) {
bool Changed = false;
for (Function &F : M.functions())
// We only infer things using the prototype and the name; we don't need
// definitions.
if (F.isDeclaration() && !F.hasOptNone())
Changed |= inferLibFuncAttributes(F, GetTLI(F));
return Changed;
}
PreservedAnalyses InferFunctionAttrsPass::run(Module &M,
ModuleAnalysisManager &AM) {
FunctionAnalysisManager &FAM =
AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
auto GetTLI = [&FAM](Function &F) -> TargetLibraryInfo & {
return FAM.getResult<TargetLibraryAnalysis>(F);
};
if (!inferAllPrototypeAttributes(M, GetTLI))
// If we didn't infer anything, preserve all analyses.
return PreservedAnalyses::all();
// Otherwise, we may have changed fundamental function attributes, so clear
// out all the passes.
return PreservedAnalyses::none();
}
namespace {
struct InferFunctionAttrsLegacyPass : public ModulePass {
static char ID; // Pass identification, replacement for typeid
InferFunctionAttrsLegacyPass() : ModulePass(ID) {
initializeInferFunctionAttrsLegacyPassPass(
*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<TargetLibraryInfoWrapperPass>();
}
bool runOnModule(Module &M) override {
if (skipModule(M))
return false;
auto GetTLI = [this](Function &F) -> TargetLibraryInfo & {
return this->getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
};
return inferAllPrototypeAttributes(M, GetTLI);
}
};
}
char InferFunctionAttrsLegacyPass::ID = 0;
INITIALIZE_PASS_BEGIN(InferFunctionAttrsLegacyPass, "inferattrs",
"Infer set function attributes", false, false)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_END(InferFunctionAttrsLegacyPass, "inferattrs",
"Infer set function attributes", false, false)
Pass *llvm::createInferFunctionAttrsLegacyPass() {
return new InferFunctionAttrsLegacyPass();
}