Move enabling the local stack allocation pass into the target where it belongs.
For now it's still a command line option, but the interface to the generic
code doesn't need to know that.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111942 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Target/TargetRegisterInfo.h b/include/llvm/Target/TargetRegisterInfo.h
index 43b6bad..4924998 100644
--- a/include/llvm/Target/TargetRegisterInfo.h
+++ b/include/llvm/Target/TargetRegisterInfo.h
@@ -593,6 +593,13 @@
return false;
}
+ /// requiresVirtualBaseRegisters - Returns true if the target wants the
+ /// LocalStackAllocation pass to be run and virtual base registers
+ /// used for more efficient stack access.
+ virtual bool requiresVirtualBaseRegisters(const MachineFunction &MF) const {
+ return false;
+ }
+
/// hasFP - Return true if the specified function should have a dedicated
/// frame pointer register. For most targets this is true only if the function
/// has variable sized allocas or if frame pointer elimination is disabled.
diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index b856d90..80dbb98 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -74,16 +74,6 @@
static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
cl::desc("Verify generated machine code"),
cl::init(getenv("LLVM_VERIFY_MACHINEINSTRS")!=NULL));
-// Enabled or disable local stack object block allocation. This is an
-// experimental pass that allocates locals relative to one another before
-// register allocation and then assigns them to actual stack slots as a block
-// later in PEI. This will eventually allow targets with limited index offset
-// range to allocate additional base registers (not just FP and SP) to
-// more efficiently reference locals, as well as handle situations where
-// locals cannot be referenced via SP or FP at all (dynamic stack realignment
-// together with variable sized objects, for example).
-cl::opt<bool> EnableLocalStackAlloc("enable-local-stack-alloc", cl::init(false),
- cl::Hidden, cl::desc("Enable pre-regalloc stack frame index allocation"));
static cl::opt<cl::boolOrDefault>
AsmVerbose("asm-verbose", cl::desc("Add comments to directives."),
@@ -354,11 +344,9 @@
if (OptLevel != CodeGenOpt::None)
PM.add(createOptimizePHIsPass());
- // Assign local variables to stack slots relative to one another and simplify
- // frame index references where possible. Final stack slot locations will be
- // assigned in PEI.
- if (EnableLocalStackAlloc)
- PM.add(createLocalStackSlotAllocationPass());
+ // If the target requests it, assign local variables to stack slots relative
+ // to one another and simplify frame index references where possible.
+ PM.add(createLocalStackSlotAllocationPass());
if (OptLevel != CodeGenOpt::None) {
// With optimization, dead code should already be eliminated. However
diff --git a/lib/CodeGen/LocalStackSlotAllocation.cpp b/lib/CodeGen/LocalStackSlotAllocation.cpp
index 811cb07..3f79593 100644
--- a/lib/CodeGen/LocalStackSlotAllocation.cpp
+++ b/lib/CodeGen/LocalStackSlotAllocation.cpp
@@ -74,10 +74,12 @@
bool LocalStackSlotPass::runOnMachineFunction(MachineFunction &MF) {
MachineFrameInfo *MFI = MF.getFrameInfo();
+ const TargetRegisterInfo *TRI = MF.getTarget().getRegisterInfo();
unsigned LocalObjectCount = MFI->getObjectIndexEnd();
- // Early exit if there are no locals to consider
- if (!LocalObjectCount)
+ // If the target doesn't want/need this pass, or if there are no locals
+ // to consider, early exit.
+ if (!TRI->requiresVirtualBaseRegisters(MF) || LocalObjectCount == 0)
return true;
// Make sure we have enough space to store the local offsets.
diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp
index e360f2c..4c3e796 100644
--- a/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/lib/CodeGen/PrologEpilogInserter.cpp
@@ -41,10 +41,6 @@
using namespace llvm;
-// FIXME: For testing purposes only. Remove once the pre-allocation pass
-// is done.
-extern cl::opt<bool> EnableLocalStackAlloc;
-
char PEI::ID = 0;
INITIALIZE_PASS(PEI, "prologepilog",
@@ -560,7 +556,7 @@
// check for whether the frame is large enough to want to use virtual
// frame index registers. Functions which don't want/need this optimization
// will continue to use the existing code path.
- if (EnableLocalStackAlloc && MFI->getUseLocalStackAllocationBlock()) {
+ if (MFI->getUseLocalStackAllocationBlock()) {
unsigned Align = MFI->getLocalFrameMaxAlign();
// Adjust to alignment boundary.
diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index cf6507b..edfacc7 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -43,9 +43,12 @@
cl::opt<bool>
ReuseFrameIndexVals("arm-reuse-frame-index-vals", cl::Hidden, cl::init(true),
cl::desc("Reuse repeated frame index values"));
-cl::opt<bool>
+static cl::opt<bool>
ForceAllBaseRegAlloc("arm-force-base-reg-alloc", cl::Hidden, cl::init(true),
cl::desc("Force use of virtual base registers for stack load/store"));
+static cl::opt<bool>
+EnableLocalStackAlloc("enable-local-stack-alloc", cl::init(false), cl::Hidden,
+ cl::desc("Enable pre-regalloc stack frame index allocation"));
}
using namespace llvm;
@@ -1285,6 +1288,11 @@
return true;
}
+bool ARMBaseRegisterInfo::
+requiresVirtualBaseRegisters(const MachineFunction &MF) const {
+ return EnableLocalStackAlloc;
+}
+
// hasReservedCallFrame - Under normal circumstances, when a frame pointer is
// not required, we reserve argument space for call sites in the function
// immediately on entry to the current function. This eliminates the need for
diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.h b/lib/Target/ARM/ARMBaseRegisterInfo.h
index afd43ea..7044b74 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.h
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.h
@@ -154,6 +154,8 @@
virtual bool requiresFrameIndexScavenging(const MachineFunction &MF) const;
+ virtual bool requiresVirtualBaseRegisters(const MachineFunction &MF) const;
+
virtual bool hasReservedCallFrame(const MachineFunction &MF) const;
virtual bool canSimplifyCallFramePseudos(const MachineFunction &MF) const;