llvm-6502/lib/Target/SystemZ/SystemZTargetMachine.cpp
Eric Christopher 04bcc11905 Move DataLayout back to the TargetMachine from TargetSubtargetInfo
derived classes.

Since global data alignment, layout, and mangling is often based on the
DataLayout, move it to the TargetMachine. This ensures that global
data is going to be layed out and mangled consistently if the subtarget
changes on a per function basis. Prior to this all targets(*) have
had subtarget dependent code moved out and onto the TargetMachine.

*One target hasn't been migrated as part of this change: R600. The
R600 port has, as a subtarget feature, the size of pointers and
this affects global data layout. I've currently hacked in a FIXME
to enable progress, but the port needs to be updated to either pass
the 64-bitness to the TargetMachine, or fix the DataLayout to
avoid subtarget dependent features.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227113 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-26 19:03:15 +00:00

107 lines
4.2 KiB
C++

//===-- SystemZTargetMachine.cpp - Define TargetMachine for SystemZ -------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "SystemZTargetMachine.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
using namespace llvm;
extern "C" void LLVMInitializeSystemZTarget() {
// Register the target.
RegisterTargetMachine<SystemZTargetMachine> X(TheSystemZTarget);
}
SystemZTargetMachine::SystemZTargetMachine(const Target &T, StringRef TT,
StringRef CPU, StringRef FS,
const TargetOptions &Options,
Reloc::Model RM, CodeModel::Model CM,
CodeGenOpt::Level OL)
: LLVMTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL),
TLOF(make_unique<TargetLoweringObjectFileELF>()),
// Make sure that global data has at least 16 bits of alignment by
// default, so that we can refer to it using LARL. We don't have any
// special requirements for stack variables though.
DL("E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-a:8:16-n32:64"),
Subtarget(TT, CPU, FS, *this) {
initAsmInfo();
}
SystemZTargetMachine::~SystemZTargetMachine() {}
namespace {
/// SystemZ Code Generator Pass Configuration Options.
class SystemZPassConfig : public TargetPassConfig {
public:
SystemZPassConfig(SystemZTargetMachine *TM, PassManagerBase &PM)
: TargetPassConfig(TM, PM) {}
SystemZTargetMachine &getSystemZTargetMachine() const {
return getTM<SystemZTargetMachine>();
}
void addIRPasses() override;
bool addInstSelector() override;
void addPreSched2() override;
void addPreEmitPass() override;
};
} // end anonymous namespace
void SystemZPassConfig::addIRPasses() {
TargetPassConfig::addIRPasses();
}
bool SystemZPassConfig::addInstSelector() {
addPass(createSystemZISelDag(getSystemZTargetMachine(), getOptLevel()));
return false;
}
void SystemZPassConfig::addPreSched2() {
if (getOptLevel() != CodeGenOpt::None &&
getSystemZTargetMachine().getSubtargetImpl()->hasLoadStoreOnCond())
addPass(&IfConverterID);
}
void SystemZPassConfig::addPreEmitPass() {
// We eliminate comparisons here rather than earlier because some
// transformations can change the set of available CC values and we
// generally want those transformations to have priority. This is
// especially true in the commonest case where the result of the comparison
// is used by a single in-range branch instruction, since we will then
// be able to fuse the compare and the branch instead.
//
// For example, two-address NILF can sometimes be converted into
// three-address RISBLG. NILF produces a CC value that indicates whether
// the low word is zero, but RISBLG does not modify CC at all. On the
// other hand, 64-bit ANDs like NILL can sometimes be converted to RISBG.
// The CC value produced by NILL isn't useful for our purposes, but the
// value produced by RISBG can be used for any comparison with zero
// (not just equality). So there are some transformations that lose
// CC values (while still being worthwhile) and others that happen to make
// the CC result more useful than it was originally.
//
// Another reason is that we only want to use BRANCH ON COUNT in cases
// where we know that the count register is not going to be spilled.
//
// Doing it so late makes it more likely that a register will be reused
// between the comparison and the branch, but it isn't clear whether
// preventing that would be a win or not.
if (getOptLevel() != CodeGenOpt::None)
addPass(createSystemZElimComparePass(getSystemZTargetMachine()), false);
if (getOptLevel() != CodeGenOpt::None)
addPass(createSystemZShortenInstPass(getSystemZTargetMachine()), false);
addPass(createSystemZLongBranchPass(getSystemZTargetMachine()));
}
TargetPassConfig *SystemZTargetMachine::createPassConfig(PassManagerBase &PM) {
return new SystemZPassConfig(this, PM);
}