// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
-//
-// This file implements a simple interprocedural pass which walks the
-// call-graph, looking for functions which do not access or only read
-// non-local memory, and marking them readnone/readonly. It does the
-// same with function arguments independently, marking them readonly/
-// readnone/nocapture. Finally, well-known library call declarations
-// are marked with all attributes that are consistent with the
-// function's standard definition. This pass is implemented as a
-// bottom-up traversal of the call-graph.
-//
+///
+/// \file
+/// This file implements interprocedural passes which walk the
+/// call-graph deducing and/or propagating function attributes.
+///
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO.h"
STATISTIC(NumReadOnlyArg, "Number of arguments marked readonly");
STATISTIC(NumNoAlias, "Number of function returns marked noalias");
STATISTIC(NumNonNullReturn, "Number of function returns marked nonnull");
-STATISTIC(NumAnnotated, "Number of attributes added to library functions");
STATISTIC(NumNoRecurse, "Number of functions marked as norecurse");
-static cl::list<std::string>
-ForceAttributes("force-attribute", cl::Hidden,
- cl::desc("Add an attribute to a function. This should be a "
- "pair of 'function-name:attribute-name', for "
- "example -force-add-attribute=foo:noinline. This "
- "option can be specified multiple times."));
-
namespace {
typedef SmallSetVector<Function *, 8> SCCNodeSet;
}
namespace {
-struct FunctionAttrs : public CallGraphSCCPass {
+struct PostOrderFunctionAttrs : public CallGraphSCCPass {
static char ID; // Pass identification, replacement for typeid
- FunctionAttrs() : CallGraphSCCPass(ID) {
- initializeFunctionAttrsPass(*PassRegistry::getPassRegistry());
+ PostOrderFunctionAttrs() : CallGraphSCCPass(ID) {
+ initializePostOrderFunctionAttrsPass(*PassRegistry::getPassRegistry());
}
bool runOnSCC(CallGraphSCC &SCC) override;
- bool doInitialization(CallGraph &CG) override {
- Revisit.clear();
- return false;
- }
- bool doFinalization(CallGraph &CG) override;
-
+
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
AU.addRequired<AssumptionCacheTracker>();
private:
TargetLibraryInfo *TLI;
- SmallVector<WeakVH,16> Revisit;
};
}
-char FunctionAttrs::ID = 0;
-INITIALIZE_PASS_BEGIN(FunctionAttrs, "functionattrs",
+char PostOrderFunctionAttrs::ID = 0;
+INITIALIZE_PASS_BEGIN(PostOrderFunctionAttrs, "functionattrs",
"Deduce function attributes", false, false)
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
-INITIALIZE_PASS_END(FunctionAttrs, "functionattrs",
+INITIALIZE_PASS_END(PostOrderFunctionAttrs, "functionattrs",
"Deduce function attributes", false, false)
-Pass *llvm::createFunctionAttrsPass() { return new FunctionAttrs(); }
+Pass *llvm::createPostOrderFunctionAttrsPass() { return new PostOrderFunctionAttrs(); }
namespace {
/// The three kinds of memory access relevant to 'readonly' and
return MadeChange;
}
-static void setDoesNotAccessMemory(Function &F) {
- if (!F.doesNotAccessMemory()) {
- F.setDoesNotAccessMemory();
- ++NumAnnotated;
- }
-}
-
-static void setOnlyReadsMemory(Function &F) {
- if (!F.onlyReadsMemory()) {
- F.setOnlyReadsMemory();
- ++NumAnnotated;
- }
-}
-
-static void setDoesNotThrow(Function &F) {
- if (!F.doesNotThrow()) {
- F.setDoesNotThrow();
- ++NumAnnotated;
- }
-}
-
-static void setDoesNotCapture(Function &F, unsigned n) {
- if (!F.doesNotCapture(n)) {
- F.setDoesNotCapture(n);
- ++NumAnnotated;
- }
-}
-
-static void setOnlyReadsMemory(Function &F, unsigned n) {
- if (!F.onlyReadsMemory(n)) {
- F.setOnlyReadsMemory(n);
- ++NumAnnotated;
- }
-}
-
-static void setDoesNotAlias(Function &F, unsigned n) {
- if (!F.doesNotAlias(n)) {
- F.setDoesNotAlias(n);
- ++NumAnnotated;
- }
-}
-
static bool setDoesNotRecurse(Function &F) {
if (F.doesNotRecurse())
return false;
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;
-
- switch (TheLibFunc) {
- case LibFunc::strlen:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setOnlyReadsMemory(F);
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::strchr:
- case LibFunc::strrchr:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isIntegerTy())
- return false;
- setOnlyReadsMemory(F);
- setDoesNotThrow(F);
- break;
- 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;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- break;
- 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;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::strxfrm:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- 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;
- setOnlyReadsMemory(F);
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::strstr:
- case LibFunc::strpbrk:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setOnlyReadsMemory(F);
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::strtok:
- case LibFunc::strtok_r:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::scanf:
- if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::setbuf:
- case LibFunc::setvbuf:
- if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::strdup:
- case LibFunc::strndup:
- if (FTy->getNumParams() < 1 || !FTy->getReturnType()->isPointerTy() ||
- !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::stat:
- case LibFunc::statvfs:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::sscanf:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::sprintf:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::snprintf:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(2)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 3);
- setOnlyReadsMemory(F, 3);
- break;
- case LibFunc::setitimer:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy() ||
- !FTy->getParamType(2)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- setDoesNotCapture(F, 3);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::system:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- // May throw; "system" is a valid pthread cancellation point.
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::malloc:
- if (FTy->getNumParams() != 1 || !FTy->getReturnType()->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- break;
- case LibFunc::memcmp:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setOnlyReadsMemory(F);
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::memchr:
- case LibFunc::memrchr:
- if (FTy->getNumParams() != 3)
- return false;
- setOnlyReadsMemory(F);
- setDoesNotThrow(F);
- break;
- case LibFunc::modf:
- case LibFunc::modff:
- case LibFunc::modfl:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::memcpy:
- case LibFunc::memccpy:
- case LibFunc::memmove:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::memalign:
- if (!FTy->getReturnType()->isPointerTy())
- return false;
- setDoesNotAlias(F, 0);
- break;
- case LibFunc::mkdir:
- if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::mktime:
- if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::realloc:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getReturnType()->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::read:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
- return false;
- // May throw; "read" is a valid pthread cancellation point.
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::rewind:
- if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::rmdir:
- case LibFunc::remove:
- case LibFunc::realpath:
- if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::rename:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::readlink:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::write:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
- return false;
- // May throw; "write" is a valid pthread cancellation point.
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::bcopy:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::bcmp:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setOnlyReadsMemory(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::bzero:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::calloc:
- if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- break;
- case LibFunc::chmod:
- case LibFunc::chown:
- if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::ctermid:
- case LibFunc::clearerr:
- case LibFunc::closedir:
- if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::atoi:
- case LibFunc::atol:
- case LibFunc::atof:
- case LibFunc::atoll:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setOnlyReadsMemory(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::access:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::fopen:
- if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
- !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::fdopen:
- if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- 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;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::ferror:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F);
- break;
- 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;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::fgets:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(2)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 3);
- break;
- case LibFunc::fread:
- if (FTy->getNumParams() != 4 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(3)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 4);
- break;
- case LibFunc::fwrite:
- if (FTy->getNumParams() != 4 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(3)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 4);
- break;
- case LibFunc::fputs:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::fscanf:
- case LibFunc::fprintf:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::fgetpos:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::getc:
- case LibFunc::getlogin_r:
- case LibFunc::getc_unlocked:
- if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::getenv:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setOnlyReadsMemory(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::gets:
- case LibFunc::getchar:
- setDoesNotThrow(F);
- break;
- case LibFunc::getitimer:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::getpwnam:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::ungetc:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::uname:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::unlink:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::unsetenv:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::utime:
- case LibFunc::utimes:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::putc:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::puts:
- case LibFunc::printf:
- case LibFunc::perror:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::pread:
- if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
- return false;
- // May throw; "pread" is a valid pthread cancellation point.
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::pwrite:
- if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
- return false;
- // May throw; "pwrite" is a valid pthread cancellation point.
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::putchar:
- setDoesNotThrow(F);
- break;
- case LibFunc::popen:
- if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
- !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::pclose:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::vscanf:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::vsscanf:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy() ||
- !FTy->getParamType(2)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::vfscanf:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy() ||
- !FTy->getParamType(2)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::valloc:
- if (!FTy->getReturnType()->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- break;
- case LibFunc::vprintf:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::vfprintf:
- case LibFunc::vsprintf:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::vsnprintf:
- if (FTy->getNumParams() != 4 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(2)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 3);
- setOnlyReadsMemory(F, 3);
- break;
- case LibFunc::open:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
- return false;
- // May throw; "open" is a valid pthread cancellation point.
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::opendir:
- if (FTy->getNumParams() != 1 || !FTy->getReturnType()->isPointerTy() ||
- !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::tmpfile:
- if (!FTy->getReturnType()->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- break;
- case LibFunc::times:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::htonl:
- case LibFunc::htons:
- case LibFunc::ntohl:
- case LibFunc::ntohs:
- setDoesNotThrow(F);
- setDoesNotAccessMemory(F);
- break;
- case LibFunc::lstat:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::lchown:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::qsort:
- if (FTy->getNumParams() != 4 || !FTy->getParamType(3)->isPointerTy())
- return false;
- // May throw; places call through function pointer.
- setDoesNotCapture(F, 4);
- break;
- case LibFunc::dunder_strdup:
- case LibFunc::dunder_strndup:
- if (FTy->getNumParams() < 1 || !FTy->getReturnType()->isPointerTy() ||
- !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::dunder_strtok_r:
- if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::under_IO_getc:
- if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::under_IO_putc:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::dunder_isoc99_scanf:
- if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::stat64:
- case LibFunc::lstat64:
- case LibFunc::statvfs64:
- if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- break;
- case LibFunc::dunder_isoc99_sscanf:
- if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::fopen64:
- if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
- !FTy->getParamType(0)->isPointerTy() ||
- !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- setOnlyReadsMemory(F, 1);
- setOnlyReadsMemory(F, 2);
- break;
- case LibFunc::fseeko64:
- case LibFunc::ftello64:
- if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- break;
- case LibFunc::tmpfile64:
- if (!FTy->getReturnType()->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotAlias(F, 0);
- break;
- case LibFunc::fstat64:
- case LibFunc::fstatvfs64:
- if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
- return false;
- setDoesNotThrow(F);
- setDoesNotCapture(F, 2);
- break;
- case LibFunc::open64:
- if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
- return false;
- // May throw; "open" is a valid pthread cancellation point.
- setDoesNotCapture(F, 1);
- setOnlyReadsMemory(F, 1);
- break;
- 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.
- setDoesNotThrow(F);
- setDoesNotCapture(F, 1);
- setDoesNotCapture(F, 2);
- break;
- default:
- // Didn't mark any attributes.
- return false;
- }
-
- return true;
-}
-
-static bool addNoRecurseAttrs(const CallGraphSCC &SCC,
- SmallVectorImpl<WeakVH> &Revisit) {
+static bool addNoRecurseAttrs(const CallGraphSCC &SCC) {
// Try and identify functions that do not recurse.
// If the SCC contains multiple nodes we know for sure there is recursion.
// Function calls a potentially recursive function.
return setDoesNotRecurse(*F);
- // We know that F is not obviously recursive, but we haven't been able to
- // prove that it doesn't actually recurse. Add it to the Revisit list to try
- // again top-down later.
- Revisit.push_back(F);
- return false;
-}
-
-static bool addNoRecurseAttrsTopDownOnly(Function *F) {
- // If F is internal and all uses are in norecurse functions, then F is also
- // norecurse.
- if (F->doesNotRecurse())
- return false;
- if (F->hasInternalLinkage()) {
- for (auto *U : F->users())
- if (auto *I = dyn_cast<Instruction>(U)) {
- if (!I->getParent()->getParent()->doesNotRecurse())
- return false;
- } else {
- return false;
- }
- return setDoesNotRecurse(*F);
- }
+ // Nothing else we can deduce usefully during the postorder traversal.
return false;
}
-static Attribute::AttrKind parseAttrKind(StringRef Kind) {
- return StringSwitch<Attribute::AttrKind>(Kind)
- .Case("alwaysinline", Attribute::AlwaysInline)
- .Case("builtin", Attribute::Builtin)
- .Case("cold", Attribute::Cold)
- .Case("convergent", Attribute::Convergent)
- .Case("inlinehint", Attribute::InlineHint)
- .Case("jumptable", Attribute::JumpTable)
- .Case("minsize", Attribute::MinSize)
- .Case("naked", Attribute::Naked)
- .Case("nobuiltin", Attribute::NoBuiltin)
- .Case("noduplicate", Attribute::NoDuplicate)
- .Case("noimplicitfloat", Attribute::NoImplicitFloat)
- .Case("noinline", Attribute::NoInline)
- .Case("nonlazybind", Attribute::NonLazyBind)
- .Case("noredzone", Attribute::NoRedZone)
- .Case("noreturn", Attribute::NoReturn)
- .Case("norecurse", Attribute::NoRecurse)
- .Case("nounwind", Attribute::NoUnwind)
- .Case("optnone", Attribute::OptimizeNone)
- .Case("optsize", Attribute::OptimizeForSize)
- .Case("readnone", Attribute::ReadNone)
- .Case("readonly", Attribute::ReadOnly)
- .Case("argmemonly", Attribute::ArgMemOnly)
- .Case("returns_twice", Attribute::ReturnsTwice)
- .Case("safestack", Attribute::SafeStack)
- .Case("sanitize_address", Attribute::SanitizeAddress)
- .Case("sanitize_memory", Attribute::SanitizeMemory)
- .Case("sanitize_thread", Attribute::SanitizeThread)
- .Case("ssp", Attribute::StackProtect)
- .Case("sspreq", Attribute::StackProtectReq)
- .Case("sspstrong", Attribute::StackProtectStrong)
- .Case("uwtable", Attribute::UWTable)
- .Default(Attribute::None);
-}
-
-/// If F has any forced attributes given on the command line, add them.
-static bool addForcedAttributes(Function *F) {
- bool Changed = false;
- for (auto &S : ForceAttributes) {
- auto KV = StringRef(S).split(':');
- if (KV.first != F->getName())
- continue;
-
- auto Kind = parseAttrKind(KV.second);
- if (Kind == Attribute::None) {
- DEBUG(dbgs() << "ForcedAttribute: " << KV.second
- << " unknown or not handled!\n");
- continue;
- }
- if (F->hasFnAttribute(Kind))
- continue;
- Changed = true;
- F->addFnAttr(Kind);
- }
- return Changed;
-}
-
-bool FunctionAttrs::runOnSCC(CallGraphSCC &SCC) {
+bool PostOrderFunctionAttrs::runOnSCC(CallGraphSCC &SCC) {
TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
bool Changed = false;
continue;
}
- // When initially processing functions, also infer their prototype
- // attributes if they are declarations.
- if (F->isDeclaration())
- Changed |= inferPrototypeAttributes(*F, *TLI);
-
- Changed |= addForcedAttributes(F);
SCCNodes.insert(F);
}
Changed |= addReadAttrs(SCCNodes, AARGetter);
Changed |= addArgumentAttrs(SCCNodes);
- // If we have no external nodes participating in the SCC, we can infer some
+ // If we have no external nodes participating in the SCC, we can deduce some
// more precise attributes as well.
if (!ExternalNode) {
Changed |= addNoAliasAttrs(SCCNodes);
Changed |= addNonNullAttrs(SCCNodes, *TLI);
}
-
- Changed |= addNoRecurseAttrs(SCC, Revisit);
+
+ Changed |= addNoRecurseAttrs(SCC);
return Changed;
}
-bool FunctionAttrs::doFinalization(CallGraph &CG) {
+namespace {
+/// A pass to do RPO deduction and propagation of function attributes.
+///
+/// This pass provides a general RPO or "top down" propagation of
+/// function attributes. For a few (rare) cases, we can deduce significantly
+/// more about function attributes by working in RPO, so this pass
+/// provides the compliment to the post-order pass above where the majority of
+/// deduction is performed.
+// FIXME: Currently there is no RPO CGSCC pass structure to slide into and so
+// this is a boring module pass, but eventually it should be an RPO CGSCC pass
+// when such infrastructure is available.
+struct ReversePostOrderFunctionAttrs : public ModulePass {
+ static char ID; // Pass identification, replacement for typeid
+ ReversePostOrderFunctionAttrs() : ModulePass(ID) {
+ initializeReversePostOrderFunctionAttrsPass(*PassRegistry::getPassRegistry());
+ }
+
+ bool runOnModule(Module &M) override;
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.setPreservesCFG();
+ AU.addRequired<CallGraphWrapperPass>();
+ }
+};
+}
+
+char ReversePostOrderFunctionAttrs::ID = 0;
+INITIALIZE_PASS_BEGIN(ReversePostOrderFunctionAttrs, "rpo-functionattrs",
+ "Deduce function attributes in RPO", false, false)
+INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
+INITIALIZE_PASS_END(ReversePostOrderFunctionAttrs, "rpo-functionattrs",
+ "Deduce function attributes in RPO", false, false)
+
+Pass *llvm::createReversePostOrderFunctionAttrsPass() {
+ return new ReversePostOrderFunctionAttrs();
+}
+
+static bool addNoRecurseAttrsTopDown(Function &F) {
+ // We check the preconditions for the function prior to calling this to avoid
+ // the cost of building up a reversible post-order list. We assert them here
+ // to make sure none of the invariants this relies on were violated.
+ assert(!F.isDeclaration() && "Cannot deduce norecurse without a definition!");
+ assert(!F.doesNotRecurse() &&
+ "This function has already been deduced as norecurs!");
+ assert(F.hasInternalLinkage() &&
+ "Can only do top-down deduction for internal linkage functions!");
+
+ // If F is internal and all of its uses are calls from a non-recursive
+ // functions, then none of its calls could in fact recurse without going
+ // through a function marked norecurse, and so we can mark this function too
+ // as norecurse. Note that the uses must actually be calls -- otherwise
+ // a pointer to this function could be returned from a norecurse function but
+ // this function could be recursively (indirectly) called. Note that this
+ // also detects if F is directly recursive as F is not yet marked as
+ // a norecurse function.
+ for (auto *U : F.users()) {
+ auto *I = dyn_cast<Instruction>(U);
+ if (!I)
+ return false;
+ CallSite CS(I);
+ if (!CS || !CS.getParent()->getParent()->doesNotRecurse())
+ return false;
+ }
+ return setDoesNotRecurse(F);
+}
+
+bool ReversePostOrderFunctionAttrs::runOnModule(Module &M) {
+ // We only have a post-order SCC traversal (because SCCs are inherently
+ // discovered in post-order), so we accumulate them in a vector and then walk
+ // it in reverse. This is simpler than using the RPO iterator infrastructure
+ // because we need to combine SCC detection and the PO walk of the call
+ // graph. We can also cheat egregiously because we're primarily interested in
+ // synthesizing norecurse and so we can only save the singular SCCs as SCCs
+ // with multiple functions in them will clearly be recursive.
+ auto &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
+ SmallVector<Function *, 16> Worklist;
+ for (scc_iterator<CallGraph *> I = scc_begin(&CG); !I.isAtEnd(); ++I) {
+ if (I->size() != 1)
+ continue;
+
+ Function *F = I->front()->getFunction();
+ if (F && !F->isDeclaration() && !F->doesNotRecurse() &&
+ F->hasInternalLinkage())
+ Worklist.push_back(F);
+ }
+
bool Changed = false;
- // When iterating over SCCs we visit functions in a bottom-up fashion. Some of
- // the rules we have for identifying norecurse functions work best with a
- // top-down walk, so look again at all the functions we previously marked as
- // worth revisiting, in top-down order.
- for (auto &F : reverse(Revisit))
- if (F)
- Changed |= addNoRecurseAttrsTopDownOnly(cast<Function>((Value*)F));
+ for (auto *F : reverse(Worklist))
+ Changed |= addNoRecurseAttrsTopDown(*F);
+
return Changed;
}
projects / oota-llvm.git / blobdiff