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Revert "[ARM] Promote small global constants to constant pools" 

This reverts commit r281314. Speculatively revert as it's possible this caused linker errors: http://lab.llvm.org:8011/builders/clang-native-arm-lnt/builds/19656

llvm-svn: 281327
This commit is contained in:
James Molloy 2016-09-13 12:45:51 +00:00
parent 64781ed4bb
commit 043d613791
5 changed files with 1 additions and 253 deletions
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13
llvm/lib/Target/ARM/ARMAsmPrinter.cpp
View File

@ -97,13 +97,6 @@ void ARMAsmPrinter::EmitXXStructor(const DataLayout &DL, const Constant *CV) {
OutStreamer->EmitValue(E, Size);
}
void ARMAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
if (PromotedGlobals.count(GV))
// The global was promoted into a constant pool. It should not be emitted.
return;
AsmPrinter::EmitGlobalVariable(GV);
}
/// runOnMachineFunction - This uses the EmitInstruction()
/// method to print assembly for each instruction.
///
@ -116,12 +109,6 @@ bool ARMAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
const Function* F = MF.getFunction();
const TargetMachine& TM = MF.getTarget();
// Collect all globals that had their storage promoted to a constant pool.
// Functions are emitted before variables, so this accumulates promoted
// globals from all functions in PromotedGlobals.
for (auto *GV : AFI->getGlobalsPromotedToConstantPool())
PromotedGlobals.insert(GV);
// Calculate this function's optimization goal.
unsigned OptimizationGoal;
if (F->hasFnAttribute(Attribute::OptimizeNone))

9
llvm/lib/Target/ARM/ARMAsmPrinter.h
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@ -56,12 +56,6 @@ class LLVM_LIBRARY_VISIBILITY ARMAsmPrinter : public AsmPrinter {
/// -1 if uninitialized, 0 if conflicting goals
int OptimizationGoals;
/// List of globals that have had their storage promoted to a constant
/// pool. This lives between calls to runOnMachineFunction and collects
/// data from every MachineFunction. It is used during doFinalization
/// when all non-function globals are emitted.
SmallPtrSet<const GlobalVariable*,2> PromotedGlobals;
public:
explicit ARMAsmPrinter(TargetMachine &TM,
std::unique_ptr<MCStreamer> Streamer);
@ -96,8 +90,7 @@ public:
void EmitStartOfAsmFile(Module &M) override;
void EmitEndOfAsmFile(Module &M) override;
void EmitXXStructor(const DataLayout &DL, const Constant *CV) override;
void EmitGlobalVariable(const GlobalVariable *GV) override;
// lowerOperand - Convert a MachineOperand into the equivalent MCOperand.
bool lowerOperand(const MachineOperand &MO, MCOperand &MCOp);

110
llvm/lib/Target/ARM/ARMISelLowering.cpp
View File

@ -59,24 +59,12 @@ using namespace llvm;
STATISTIC(NumTailCalls, "Number of tail calls");
STATISTIC(NumMovwMovt, "Number of GAs materialized with movw + movt");
STATISTIC(NumLoopByVals, "Number of loops generated for byval arguments");
STATISTIC(NumConstpoolPromoted,
"Number of constants with their storage promoted into constant pools");
static cl::opt<bool>
ARMInterworking("arm-interworking", cl::Hidden,
cl::desc("Enable / disable ARM interworking (for debugging only)"),
cl::init(true));
static cl::opt<bool> EnableConstpoolPromotion(
"arm-promote-constant", cl::Hidden,
cl::desc("Enable / disable promotion of unnamed_addr constants into "
"constant pools"),
cl::init(true));
static cl::opt<unsigned> ConstpoolPromotionMaxSize(
"arm-promote-constant-max-size", cl::Hidden,
cl::desc("Maximum size of constant to promote into a constant pool"),
cl::init(64));
namespace {
class ARMCCState : public CCState {
public:
@ -2975,99 +2963,6 @@ ARMTargetLowering::LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const {
llvm_unreachable("bogus TLS model");
}
/// Return true if all users of V are within function F, looking through
/// ConstantExprs.
static bool allUsersAreInFunction(const Value *V, const Function *F) {
SmallVector<const User*,4> Worklist;
for (auto *U : V->users())
Worklist.push_back(U);
while (!Worklist.empty()) {
auto *U = Worklist.pop_back_val();
if (isa<ConstantExpr>(U)) {
for (auto *UU : U->users())
Worklist.push_back(UU);
continue;
}
auto *I = dyn_cast<Instruction>(U);
if (!I || I->getParent()->getParent() != F)
return false;
}
return true;
}
/// Return true if all users of V are within some (any) function, looking through
/// ConstantExprs. In other words, are there any global constant users?
static bool allUsersAreInFunctions(const Value *V) {
SmallVector<const User*,4> Worklist;
for (auto *U : V->users())
Worklist.push_back(U);
while (!Worklist.empty()) {
auto *U = Worklist.pop_back_val();
if (isa<ConstantExpr>(U)) {
for (auto *UU : U->users())
Worklist.push_back(UU);
continue;
}
if (!isa<Instruction>(U))
return false;
}
return true;
}
static SDValue promoteToConstantPool(const GlobalValue *GV, SelectionDAG &DAG,
EVT PtrVT, SDLoc dl) {
// If we're creating a pool entry for a constant global with unnamed address,
// and the global is small enough, we can emit it inline into the constant pool
// to save ourselves an indirection.
//
// This is a win if the constant is only used in one function (so it doesn't
// need to be duplicated) or duplicating the constant wouldn't increase code
// size (implying the constant is no larger than 4 bytes).
const Function *F = DAG.getMachineFunction().getFunction();
auto *GVar = dyn_cast<GlobalVariable>(GV);
if (EnableConstpoolPromotion && GVar && GVar->hasInitializer() &&
GVar->isConstant() && GVar->hasGlobalUnnamedAddr()) {
// The constant islands pass can only really deal with alignment requests
// <= 4 bytes and cannot pad constants itself. Therefore we cannot promote
// any type wanting greater alignment requirements than 4 bytes. We also
// can only promote constants that are multiples of 4 bytes in size or
// are paddable to a multiple of 4. Currently we only try and pad constants
// that are strings for simplicity.
auto *Init = GVar->getInitializer();
auto *CDAInit = dyn_cast<ConstantDataArray>(Init);
unsigned Size = DAG.getDataLayout().getTypeAllocSize(Init->getType());
unsigned Align = DAG.getDataLayout().getABITypeAlignment(Init->getType());
unsigned RequiredPadding = 4 - (Size % 4);
bool PaddingPossible =
RequiredPadding == 4 || (CDAInit && CDAInit->isString());
if (PaddingPossible && Align <= 4 && Size <= ConstpoolPromotionMaxSize &&
(allUsersAreInFunction(GVar, F) ||
(Size <= 4 && allUsersAreInFunctions(GVar)))) {
if (RequiredPadding != 4) {
StringRef S = CDAInit->getAsString();
SmallVector<uint8_t,16> V(S.size());
std::copy(S.bytes_begin(), S.bytes_end(), V.begin());
while (RequiredPadding--)
V.push_back(0);
Init = ConstantDataArray::get(*DAG.getContext(), V);
}
SDValue CPAddr =
DAG.getTargetConstantPool(Init, PtrVT, Align);
MachineFunction &MF = DAG.getMachineFunction();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
AFI->markGlobalAsPromotedToConstantPool(GVar);
return DAG.getNode(ARMISD::Wrapper, dl, MVT::i32, CPAddr);
}
}
return SDValue();
}
SDValue ARMTargetLowering::LowerGlobalAddressELF(SDValue Op,
SelectionDAG &DAG) const {
EVT PtrVT = getPointerTy(DAG.getDataLayout());
@ -3079,11 +2974,6 @@ SDValue ARMTargetLowering::LowerGlobalAddressELF(SDValue Op,
bool IsRO =
(isa<GlobalVariable>(GV) && cast<GlobalVariable>(GV)->isConstant()) ||
isa<Function>(GV);
if (TM.shouldAssumeDSOLocal(*GV->getParent(), GV))
if (SDValue V = promoteToConstantPool(GV, DAG, PtrVT, dl))
return V;
if (isPositionIndependent()) {
bool UseGOT_PREL = !TM.shouldAssumeDSOLocal(*GV->getParent(), GV);

13
llvm/lib/Target/ARM/ARMMachineFunctionInfo.h
View File

@ -121,9 +121,6 @@ class ARMFunctionInfo : public MachineFunctionInfo {
/// copies.
bool IsSplitCSR;
/// Globals that have had their storage promoted into the constant pool.
SmallVector<const GlobalVariable*,2> PromotedGlobals;
public:
ARMFunctionInfo() :
isThumb(false),
@ -229,16 +226,6 @@ public:
}
return It;
}
/// Indicate to the backend that \c GV has had its storage changed to inside
/// a constant pool. This means it no longer needs to be emitted as a
/// global variable.
void markGlobalAsPromotedToConstantPool(const GlobalVariable *GV) {
PromotedGlobals.push_back(GV);
}
ArrayRef<const GlobalVariable*> getGlobalsPromotedToConstantPool() {
return PromotedGlobals;
}
};
} // End llvm namespace

109
llvm/test/CodeGen/ARM/constantpool-promote.ll
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@ -1,109 +0,0 @@
; RUN: llc -relocation-model=static < %s | FileCheck %s
; RUN: llc -relocation-model=pic < %s | FileCheck %s
; RUN: llc -relocation-model=ropi < %s | FileCheck %s
; RUN: llc -relocation-model=rwpi < %s | FileCheck %s
target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-n32-S64"
target triple = "armv7--linux-gnueabihf"
@.str = private unnamed_addr constant [2 x i8] c"s\00", align 1
@.str1 = private unnamed_addr constant [69 x i8] c"this string is far too long to fit in a literal pool by far and away\00", align 1
@.str2 = private unnamed_addr constant [27 x i8] c"this string is just right!\00", align 1
@.str3 = private unnamed_addr constant [26 x i8] c"this string is used twice\00", align 1
@.str4 = private unnamed_addr constant [29 x i8] c"same string in two functions\00", align 1
@.arr1 = private unnamed_addr constant [2 x i16] [i16 3, i16 4], align 2
@.arr2 = private unnamed_addr constant [2 x i16] [i16 7, i16 8], align 2
@.ptr = private unnamed_addr constant [2 x i16*] [i16* getelementptr inbounds ([2 x i16], [2 x i16]* @.arr2, i32 0, i32 0), i16* null], align 2
; CHECK-LABEL: @test1
; CHECK: adr r0, [[x:.*]]
; CHECK: [[x]]:
; CHECK: .asciz "s\000\000"
define void @test1() #0 {
tail call void @a(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i32 0, i32 0)) #2
ret void
}
declare void @a(i8*) #1
; CHECK-LABEL: @test2
; CHECK-NOT: .asci
; CHECK: .fnend
define void @test2() #0 {
tail call void @a(i8* getelementptr inbounds ([69 x i8], [69 x i8]* @.str1, i32 0, i32 0)) #2
ret void
}
; CHECK-LABEL: @test3
; CHECK: adr r0, [[x:.*]]
; CHECK: [[x]]:
; CHECK: .asciz "this string is just right!\000"
define void @test3() #0 {
tail call void @a(i8* getelementptr inbounds ([27 x i8], [27 x i8]* @.str2, i32 0, i32 0)) #2
ret void
}
; CHECK-LABEL: @test4
; CHECK: adr r{{.*}}, [[x:.*]]
; CHECK: [[x]]:
; CHECK: .asciz "this string is used twice\000\000"
define void @test4() #0 {
tail call void @a(i8* getelementptr inbounds ([26 x i8], [26 x i8]* @.str3, i32 0, i32 0)) #2
tail call void @a(i8* getelementptr inbounds ([26 x i8], [26 x i8]* @.str3, i32 0, i32 0)) #2
ret void
}
; CHECK-LABEL: @test5a
; CHECK-NOT: adr
define void @test5a() #0 {
tail call void @a(i8* getelementptr inbounds ([29 x i8], [29 x i8]* @.str4, i32 0, i32 0)) #2
ret void
}
define void @test5b() #0 {
tail call void @b(i8* getelementptr inbounds ([29 x i8], [29 x i8]* @.str4, i32 0, i32 0)) #2
ret void
}
; CHECK-LABEL: @test6a
; CHECK: adr r0, [[x:.*]]
; CHECK: [[x]]:
; CHECK: .short 3
; CHECK: .short 4
define void @test6a() #0 {
tail call void @c(i16* getelementptr inbounds ([2 x i16], [2 x i16]* @.arr1, i32 0, i32 0)) #2
ret void
}
; CHECK-LABEL: @test6b
; CHECK: adr r0, [[x:.*]]
; CHECK: [[x]]:
; CHECK: .short 3
; CHECK: .short 4
define void @test6b() #0 {
tail call void @c(i16* getelementptr inbounds ([2 x i16], [2 x i16]* @.arr1, i32 0, i32 0)) #2
ret void
}
; This shouldn't be promoted, as the string is used by another global.
; CHECK-LABEL: @test7
; CHECK-NOT: adr
define void @test7() #0 {
tail call void @c(i16* getelementptr inbounds ([2 x i16], [2 x i16]* @.arr2, i32 0, i32 0)) #2
ret void
}
declare void @b(i8*) #1
declare void @c(i16*) #1
attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #2 = { nounwind }
!llvm.module.flags = !{!0, !1}
!llvm.ident = !{!2}
!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 1, !"min_enum_size", i32 4}
!2 = !{!"Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)"}