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llvm-project/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp

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//===- InferFunctionAttrs.cpp - Infer implicit function attributes --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO/InferFunctionAttrs.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/MemoryBuiltins.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"
using namespace llvm;
#define DEBUG_TYPE "inferattrs"
STATISTIC(NumReadNone, "Number of functions inferred as readnone");
STATISTIC(NumReadOnly, "Number of functions inferred as readonly");
STATISTIC(NumArgMemOnly, "Number of functions inferred as argmemonly");
STATISTIC(NumNoUnwind, "Number of functions inferred as nounwind");
STATISTIC(NumNoCapture, "Number of arguments inferred as nocapture");
STATISTIC(NumReadOnlyArg, "Number of arguments inferred as readonly");
STATISTIC(NumNoAlias, "Number of function returns inferred as noalias");
STATISTIC(NumNonNull, "Number of function returns inferred as nonnull returns");
static bool setDoesNotAccessMemory(Function &F) {
if (F.doesNotAccessMemory())
return false;
F.setDoesNotAccessMemory();
++NumReadNone;
return true;
}
static bool setOnlyReadsMemory(Function &F) {
if (F.onlyReadsMemory())
return false;
F.setOnlyReadsMemory();
++NumReadOnly;
return true;
}
static bool setOnlyAccessesArgMemory(Function &F) {
if (F.onlyAccessesArgMemory())
return false;
F.setOnlyAccessesArgMemory ();
++NumArgMemOnly;
return true;
}
static bool setDoesNotThrow(Function &F) {
if (F.doesNotThrow())
return false;
F.setDoesNotThrow();
++NumNoUnwind;
return true;
}
static bool setDoesNotCapture(Function &F, unsigned n) {
if (F.doesNotCapture(n))
return false;
F.setDoesNotCapture(n);
++NumNoCapture;
return true;
}
static bool setOnlyReadsMemory(Function &F, unsigned n) {
if (F.onlyReadsMemory(n))
return false;
F.setOnlyReadsMemory(n);
++NumReadOnlyArg;
return true;
}
static bool setDoesNotAlias(Function &F, unsigned n) {
if (F.doesNotAlias(n))
return false;
F.setDoesNotAlias(n);
++NumNoAlias;
return true;
}
static bool setNonNull(Function &F, unsigned n) {
assert((n != AttributeSet::ReturnIndex ||
F.getReturnType()->isPointerTy()) &&
"nonnull applies only to pointers");
if (F.getAttributes().hasAttribute(n, Attribute::NonNull))
return false;
F.addAttribute(n, Attribute::NonNull);
++NumNonNull;
return true;
}
/// Analyze the name and prototype of the given function and set any applicable
/// attributes.
///
/// Returns true if any attributes were set and false otherwise.
static bool inferPrototypeAttributes(Function &F,
const TargetLibraryInfo &TLI) {
if (F.hasFnAttribute(Attribute::OptimizeNone))
return false;
FunctionType *FTy = F.getFunctionType();
LibFunc::Func TheLibFunc;
if (!(TLI.getLibFunc(F.getName(), TheLibFunc) && TLI.has(TheLibFunc)))
return false;
bool Changed = false;
switch (TheLibFunc) {
case LibFunc::strlen:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setOnlyReadsMemory(F);
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::strchr:
case LibFunc::strrchr:
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isIntegerTy())
return false;
Changed |= setOnlyReadsMemory(F);
Changed |= setDoesNotThrow(F);
return Changed;
case LibFunc::strtol:
case LibFunc::strtod:
case LibFunc::strtof:
case LibFunc::strtoul:
case LibFunc::strtoll:
case LibFunc::strtold:
case LibFunc::strtoull:
if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::strcpy:
case LibFunc::stpcpy:
case LibFunc::strcat:
case LibFunc::strncat:
case LibFunc::strncpy:
case LibFunc::stpncpy:
if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::strxfrm:
if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::strcmp: // 0,1
case LibFunc::strspn: // 0,1
case LibFunc::strncmp: // 0,1
case LibFunc::strcspn: // 0,1
case LibFunc::strcoll: // 0,1
case LibFunc::strcasecmp: // 0,1
case LibFunc::strncasecmp: //
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setOnlyReadsMemory(F);
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::strstr:
case LibFunc::strpbrk:
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setOnlyReadsMemory(F);
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::strtok:
case LibFunc::strtok_r:
if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::scanf:
if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::setbuf:
case LibFunc::setvbuf:
if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::strdup:
case LibFunc::strndup:
if (FTy->getNumParams() < 1 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::stat:
case LibFunc::statvfs:
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::sscanf:
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::sprintf:
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::snprintf:
if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 3);
Changed |= setOnlyReadsMemory(F, 3);
return Changed;
case LibFunc::setitimer:
if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
Changed |= setDoesNotCapture(F, 3);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::system:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
// May throw; "system" is a valid pthread cancellation point.
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::malloc:
if (FTy->getNumParams() != 1 || !FTy->getReturnType()->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
return Changed;
case LibFunc::memcmp:
if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setOnlyReadsMemory(F);
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::memchr:
case LibFunc::memrchr:
if (FTy->getNumParams() != 3)
return false;
Changed |= setOnlyReadsMemory(F);
Changed |= setDoesNotThrow(F);
return Changed;
case LibFunc::modf:
case LibFunc::modff:
case LibFunc::modfl:
if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::memcpy:
case LibFunc::memccpy:
case LibFunc::memmove:
if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::memalign:
if (!FTy->getReturnType()->isPointerTy())
return false;
Changed |= setDoesNotAlias(F, 0);
return Changed;
case LibFunc::mkdir:
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::mktime:
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::realloc:
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getReturnType()->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::read:
if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
return false;
// May throw; "read" is a valid pthread cancellation point.
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::rewind:
if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::rmdir:
case LibFunc::remove:
case LibFunc::realpath:
if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::rename:
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::readlink:
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::write:
if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
return false;
// May throw; "write" is a valid pthread cancellation point.
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::bcopy:
if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::bcmp:
if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setOnlyReadsMemory(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::bzero:
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::calloc:
if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
return Changed;
case LibFunc::chmod:
case LibFunc::chown:
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::ctermid:
case LibFunc::clearerr:
case LibFunc::closedir:
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::atoi:
case LibFunc::atol:
case LibFunc::atof:
case LibFunc::atoll:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setOnlyReadsMemory(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::access:
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::fopen:
if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::fdopen:
if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::feof:
case LibFunc::free:
case LibFunc::fseek:
case LibFunc::ftell:
case LibFunc::fgetc:
case LibFunc::fseeko:
case LibFunc::ftello:
case LibFunc::fileno:
case LibFunc::fflush:
case LibFunc::fclose:
case LibFunc::fsetpos:
case LibFunc::flockfile:
case LibFunc::funlockfile:
case LibFunc::ftrylockfile:
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::ferror:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F);
return Changed;
case LibFunc::fputc:
case LibFunc::fstat:
case LibFunc::frexp:
case LibFunc::frexpf:
case LibFunc::frexpl:
case LibFunc::fstatvfs:
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::fgets:
if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 3);
return Changed;
case LibFunc::fread:
if (FTy->getNumParams() != 4 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(3)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 4);
return Changed;
case LibFunc::fwrite:
if (FTy->getNumParams() != 4 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(3)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 4);
return Changed;
case LibFunc::fputs:
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::fscanf:
case LibFunc::fprintf:
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::fgetpos:
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::getc:
case LibFunc::getlogin_r:
case LibFunc::getc_unlocked:
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::getenv:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setOnlyReadsMemory(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::gets:
case LibFunc::getchar:
Changed |= setDoesNotThrow(F);
return Changed;
case LibFunc::getitimer:
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::getpwnam:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::ungetc:
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::uname:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::unlink:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::unsetenv:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::utime:
case LibFunc::utimes:
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::putc:
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::puts:
case LibFunc::printf:
case LibFunc::perror:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::pread:
if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
return false;
// May throw; "pread" is a valid pthread cancellation point.
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::pwrite:
if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
return false;
// May throw; "pwrite" is a valid pthread cancellation point.
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::putchar:
Changed |= setDoesNotThrow(F);
return Changed;
case LibFunc::popen:
if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::pclose:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::vscanf:
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::vsscanf:
if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::vfscanf:
if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::valloc:
if (!FTy->getReturnType()->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
return Changed;
case LibFunc::vprintf:
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::vfprintf:
case LibFunc::vsprintf:
if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::vsnprintf:
if (FTy->getNumParams() != 4 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 3);
Changed |= setOnlyReadsMemory(F, 3);
return Changed;
case LibFunc::open:
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
return false;
// May throw; "open" is a valid pthread cancellation point.
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::opendir:
if (FTy->getNumParams() != 1 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::tmpfile:
if (!FTy->getReturnType()->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
return Changed;
case LibFunc::times:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::htonl:
case LibFunc::htons:
case LibFunc::ntohl:
case LibFunc::ntohs:
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAccessMemory(F);
return Changed;
case LibFunc::lstat:
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::lchown:
if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::qsort:
if (FTy->getNumParams() != 4 || !FTy->getParamType(3)->isPointerTy())
return false;
// May throw; places call through function pointer.
Changed |= setDoesNotCapture(F, 4);
return Changed;
case LibFunc::dunder_strdup:
case LibFunc::dunder_strndup:
if (FTy->getNumParams() < 1 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::dunder_strtok_r:
if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::under_IO_getc:
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::under_IO_putc:
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::dunder_isoc99_scanf:
if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::stat64:
case LibFunc::lstat64:
case LibFunc::statvfs64:
if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::dunder_isoc99_sscanf:
if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::fopen64:
if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 1);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
case LibFunc::fseeko64:
case LibFunc::ftello64:
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc::tmpfile64:
if (!FTy->getReturnType()->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotAlias(F, 0);
return Changed;
case LibFunc::fstat64:
case LibFunc::fstatvfs64:
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return false;
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::open64:
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
return false;
// May throw; "open" is a valid pthread cancellation point.
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
case LibFunc::gettimeofday:
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
// Currently some platforms have the restrict keyword on the arguments to
// gettimeofday. To be conservative, do not add noalias to gettimeofday's
// arguments.
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setDoesNotCapture(F, 2);
return Changed;
case LibFunc::Znwj: // new(unsigned int)
case LibFunc::Znwm: // new(unsigned long)
case LibFunc::Znaj: // new[](unsigned int)
case LibFunc::Znam: // new[](unsigned long)
case LibFunc::msvc_new_int: // new(unsigned int)
case LibFunc::msvc_new_longlong: // new(unsigned long long)
case LibFunc::msvc_new_array_int: // new[](unsigned int)
case LibFunc::msvc_new_array_longlong: // new[](unsigned long long)
if (FTy->getNumParams() != 1)
return false;
// Operator new always returns a nonnull noalias pointer
Changed |= setNonNull(F, AttributeSet::ReturnIndex);
Changed |= setDoesNotAlias(F, AttributeSet::ReturnIndex);
return Changed;
//TODO: add LibFunc entries for:
//case LibFunc::memset_pattern4:
//case LibFunc::memset_pattern8:
case LibFunc::memset_pattern16:
if (FTy->isVarArg() || FTy->getNumParams() != 3 ||
!isa<PointerType>(FTy->getParamType(0)) ||
!isa<PointerType>(FTy->getParamType(1)) ||
!isa<IntegerType>(FTy->getParamType(2)))
return false;
Changed |= setOnlyAccessesArgMemory(F);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
// int __nvvm_reflect(const char *)
case LibFunc::nvvm_reflect:
if (FTy->getNumParams() != 1 || !isa<PointerType>(FTy->getParamType(0)))
return false;
Changed |= setDoesNotAccessMemory(F);
Changed |= setDoesNotThrow(F);
return Changed;
default:
// FIXME: It'd be really nice to cover all the library functions we're
// aware of here.
return false;
}
}
static bool inferAllPrototypeAttributes(Module &M,
const TargetLibraryInfo &TLI) {
bool Changed = false;
for (Function &F : M.functions())
// We only infer things using the prototype if the definition isn't around
// to analyze directly.
if (F.isDeclaration())
Changed |= inferPrototypeAttributes(F, TLI);
return Changed;
}
PreservedAnalyses InferFunctionAttrsPass::run(Module &M,
AnalysisManager<Module> &AM) {
auto &TLI = AM.getResult<TargetLibraryAnalysis>(M);
if (!inferAllPrototypeAttributes(M, TLI))
// 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 {
auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
return inferAllPrototypeAttributes(M, TLI);
}
};
}
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();
}
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