r209149 - Non-allocatable Global Named Register
Renato Golin
renato.golin at linaro.org
Mon May 19 11:15:42 PDT 2014
Author: rengolin
Date: Mon May 19 13:15:42 2014
New Revision: 209149
URL: http://llvm.org/viewvc/llvm-project?rev=209149&view=rev
Log:
Non-allocatable Global Named Register
This patch implements global named registers in Clang, lowering to the just
created intrinsics in LLVM (@llvm.read/write_register). A new type of LValue
had to be created (Register), which just adds support to carry the metadata
node containing the name of the register. Two new methods to emit loads and
stores interoperate with another to emit the named metadata node.
No guarantees are being made and only non-allocatable global variable named
registers are being supported. Local named register support is unchanged.
Added:
cfe/trunk/test/CodeGen/named_reg_global.c
Modified:
cfe/trunk/include/clang/AST/Decl.h
cfe/trunk/lib/CodeGen/CGExpr.cpp
cfe/trunk/lib/CodeGen/CGValue.h
cfe/trunk/lib/CodeGen/CodeGenFunction.h
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/test/Sema/asm.c
cfe/trunk/test/Sema/decl-invalid.c
Modified: cfe/trunk/include/clang/AST/Decl.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Decl.h?rev=209149&r1=209148&r2=209149&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Decl.h (original)
+++ cfe/trunk/include/clang/AST/Decl.h Mon May 19 13:15:42 2014
@@ -826,6 +826,10 @@ public:
// Second check is for C++11 [dcl.stc]p4.
return !isFileVarDecl() && getTSCSpec() == TSCS_unspecified;
+ // Global Named Register (GNU extension)
+ if (getStorageClass() == SC_Register && !isLocalVarDecl())
+ return false;
+
// Return true for: Auto, Register.
// Return false for: Extern, Static, PrivateExtern, OpenCLWorkGroupLocal.
Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=209149&r1=209148&r2=209149&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Mon May 19 13:15:42 2014
@@ -21,6 +21,7 @@
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
+#include "clang/AST/Attr.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/IR/DataLayout.h"
@@ -1276,6 +1277,10 @@ RValue CodeGenFunction::EmitLoadOfLValue
if (LV.isExtVectorElt())
return EmitLoadOfExtVectorElementLValue(LV);
+ // Global Register variables always invoke intrinsics
+ if (LV.isGlobalReg())
+ return EmitLoadOfGlobalRegLValue(LV);
+
assert(LV.isBitField() && "Unknown LValue type!");
return EmitLoadOfBitfieldLValue(LV);
}
@@ -1343,6 +1348,16 @@ RValue CodeGenFunction::EmitLoadOfExtVec
return RValue::get(Vec);
}
+/// @brief Load of global gamed gegisters are always calls to intrinsics.
+RValue CodeGenFunction::EmitLoadOfGlobalRegLValue(LValue LV) {
+ assert(LV.getType()->isIntegerType() && "Bad type for register variable");
+ llvm::MDNode *RegName = dyn_cast<llvm::MDNode>(LV.getGlobalReg());
+ assert(RegName && "Register LValue is not metadata");
+ llvm::Type *Types[] = { CGM.getTypes().ConvertType(LV.getType()) };
+ llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::read_register, Types);
+ llvm::Value* Call = Builder.CreateCall(F, RegName);
+ return RValue::get(Call);
+}
/// EmitStoreThroughLValue - Store the specified rvalue into the specified
@@ -1370,6 +1385,9 @@ void CodeGenFunction::EmitStoreThroughLV
if (Dst.isExtVectorElt())
return EmitStoreThroughExtVectorComponentLValue(Src, Dst);
+ if (Dst.isGlobalReg())
+ return EmitStoreThroughGlobalRegLValue(Src, Dst);
+
assert(Dst.isBitField() && "Unknown LValue type");
return EmitStoreThroughBitfieldLValue(Src, Dst);
}
@@ -1581,6 +1599,17 @@ void CodeGenFunction::EmitStoreThroughEx
Store->setAlignment(Dst.getAlignment().getQuantity());
}
+/// @brief Store of global named registers are always calls to intrinsics.
+void CodeGenFunction::EmitStoreThroughGlobalRegLValue(RValue Src, LValue Dst) {
+ assert(Dst.getType()->isIntegerType() && "Bad type for register variable");
+ llvm::MDNode *RegName = dyn_cast<llvm::MDNode>(Dst.getGlobalReg());
+ assert(RegName && "Register LValue is not metadata");
+ llvm::Type *Types[] = { CGM.getTypes().ConvertType(Dst.getType()) };
+ llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::write_register, Types);
+ llvm::Value *Value = Src.getScalarVal();
+ Builder.CreateCall2(F, RegName, Value);
+}
+
// setObjCGCLValueClass - sets class of he lvalue for the purpose of
// generating write-barries API. It is currently a global, ivar,
// or neither.
@@ -1740,14 +1769,41 @@ static LValue EmitCapturedFieldLValue(Co
return CGF.EmitLValueForField(LV, FD);
}
+/// Named Registers are named metadata pointing to the register name
+/// which will be read from/written to as an argument to the intrinsic
+/// @llvm.read/write_register.
+/// So far, only the name is being passed down, but other options such as
+/// register type, allocation type or even optimization options could be
+/// passed down via the metadata node.
+static LValue EmitGlobalNamedRegister(const VarDecl *VD,
+ CodeGenModule &CGM,
+ CharUnits Alignment) {
+ AsmLabelAttr *Asm = VD->getAttr<AsmLabelAttr>();
+ llvm::Twine Name("llvm.named.register."+Asm->getLabel());
+ llvm::NamedMDNode *M = CGM.getModule().getOrInsertNamedMetadata(Name.str());
+ if (M->getNumOperands() == 0) {
+ llvm::MDString *Str = llvm::MDString::get(CGM.getLLVMContext(),
+ Asm->getLabel());
+ llvm::Value *Ops[] = { Str };
+ M->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops));
+ }
+ return LValue::MakeGlobalReg(M->getOperand(0), VD->getType(), Alignment);
+}
+
LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
const NamedDecl *ND = E->getDecl();
CharUnits Alignment = getContext().getDeclAlign(ND);
QualType T = E->getType();
+ const auto *VD = dyn_cast<VarDecl>(ND);
+
+ // Global Named registers access via intrinsics only
+ if (VD && VD->getStorageClass() == SC_Register &&
+ VD->hasAttr<AsmLabelAttr>() && !VD->isLocalVarDecl())
+ return EmitGlobalNamedRegister(VD, CGM, Alignment);
// A DeclRefExpr for a reference initialized by a constant expression can
// appear without being odr-used. Directly emit the constant initializer.
- if (const auto *VD = dyn_cast<VarDecl>(ND)) {
+ if (VD) {
const Expr *Init = VD->getAnyInitializer(VD);
if (Init && !isa<ParmVarDecl>(VD) && VD->getType()->isReferenceType() &&
VD->isUsableInConstantExpressions(getContext()) &&
@@ -1773,7 +1829,7 @@ LValue CodeGenFunction::EmitDeclRefLValu
return MakeAddrLValue(Aliasee, T, Alignment);
}
- if (const auto *VD = dyn_cast<VarDecl>(ND)) {
+ if (VD) {
// Check if this is a global variable.
if (VD->hasLinkage() || VD->isStaticDataMember())
return EmitGlobalVarDeclLValue(*this, E, VD);
Modified: cfe/trunk/lib/CodeGen/CGValue.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGValue.h?rev=209149&r1=209148&r2=209149&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGValue.h (original)
+++ cfe/trunk/lib/CodeGen/CGValue.h Mon May 19 13:15:42 2014
@@ -110,7 +110,8 @@ class LValue {
Simple, // This is a normal l-value, use getAddress().
VectorElt, // This is a vector element l-value (V[i]), use getVector*
BitField, // This is a bitfield l-value, use getBitfield*.
- ExtVectorElt // This is an extended vector subset, use getExtVectorComp
+ ExtVectorElt, // This is an extended vector subset, use getExtVectorComp
+ GlobalReg // This is a register l-value, use getGlobalReg()
} LVType;
llvm::Value *V;
@@ -192,6 +193,7 @@ public:
bool isVectorElt() const { return LVType == VectorElt; }
bool isBitField() const { return LVType == BitField; }
bool isExtVectorElt() const { return LVType == ExtVectorElt; }
+ bool isGlobalReg() const { return LVType == GlobalReg; }
bool isVolatileQualified() const { return Quals.hasVolatile(); }
bool isRestrictQualified() const { return Quals.hasRestrict(); }
@@ -286,6 +288,9 @@ public:
return *BitFieldInfo;
}
+ // global register lvalue
+ llvm::Value *getGlobalReg() const { assert(isGlobalReg()); return V; }
+
static LValue MakeAddr(llvm::Value *address, QualType type,
CharUnits alignment, ASTContext &Context,
llvm::MDNode *TBAAInfo = 0) {
@@ -335,6 +340,16 @@ public:
R.Initialize(type, type.getQualifiers(), Alignment);
return R;
}
+
+ static LValue MakeGlobalReg(llvm::Value *Reg,
+ QualType type,
+ CharUnits Alignment) {
+ LValue R;
+ R.LVType = GlobalReg;
+ R.V = Reg;
+ R.Initialize(type, type.getQualifiers(), Alignment);
+ return R;
+ }
RValue asAggregateRValue() const {
// FIMXE: Alignment
Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=209149&r1=209148&r2=209149&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Mon May 19 13:15:42 2014
@@ -1979,12 +1979,14 @@ public:
RValue EmitLoadOfLValue(LValue V, SourceLocation Loc);
RValue EmitLoadOfExtVectorElementLValue(LValue V);
RValue EmitLoadOfBitfieldLValue(LValue LV);
+ RValue EmitLoadOfGlobalRegLValue(LValue LV);
/// EmitStoreThroughLValue - Store the specified rvalue into the specified
/// lvalue, where both are guaranteed to the have the same type, and that type
/// is 'Ty'.
void EmitStoreThroughLValue(RValue Src, LValue Dst, bool isInit=false);
void EmitStoreThroughExtVectorComponentLValue(RValue Src, LValue Dst);
+ void EmitStoreThroughGlobalRegLValue(RValue Src, LValue Dst);
/// EmitStoreThroughBitfieldLValue - Store Src into Dst with same constraints
/// as EmitStoreThroughLValue.
@@ -2009,6 +2011,7 @@ public:
// Note: only available for agg return types
LValue EmitVAArgExprLValue(const VAArgExpr *E);
LValue EmitDeclRefLValue(const DeclRefExpr *E);
+ LValue EmitReadRegister(const VarDecl *VD);
LValue EmitStringLiteralLValue(const StringLiteral *E);
LValue EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E);
LValue EmitPredefinedLValue(const PredefinedExpr *E);
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=209149&r1=209148&r2=209149&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Mon May 19 13:15:42 2014
@@ -5119,13 +5119,9 @@ Sema::ActOnVariableDeclarator(Scope *S,
if (!DC->isRecord() && S->getFnParent() == 0) {
// C99 6.9p2: The storage-class specifiers auto and register shall not
// appear in the declaration specifiers in an external declaration.
- if (SC == SC_Auto || SC == SC_Register) {
- // If this is a register variable with an asm label specified, then this
- // is a GNU extension.
- if (SC == SC_Register && D.getAsmLabel())
- Diag(D.getIdentifierLoc(), diag::err_unsupported_global_register);
- else
- Diag(D.getIdentifierLoc(), diag::err_typecheck_sclass_fscope);
+ // Global Register+Asm is a GNU extension we support.
+ if (SC == SC_Auto || (SC == SC_Register && !D.getAsmLabel())) {
+ Diag(D.getIdentifierLoc(), diag::err_typecheck_sclass_fscope);
D.setInvalidType();
}
}
@@ -5437,6 +5433,7 @@ Sema::ActOnVariableDeclarator(Scope *S,
Diag(E->getExprLoc(), diag::warn_asm_label_on_auto_decl) << Label;
break;
case SC_Register:
+ // Local Named register
if (!Context.getTargetInfo().isValidGCCRegisterName(Label))
Diag(E->getExprLoc(), diag::err_asm_unknown_register_name) << Label;
break;
@@ -5446,6 +5443,10 @@ Sema::ActOnVariableDeclarator(Scope *S,
case SC_OpenCLWorkGroupLocal:
break;
}
+ } else if (SC == SC_Register) {
+ // Global Named register
+ if (!Context.getTargetInfo().isValidGCCRegisterName(Label))
+ Diag(E->getExprLoc(), diag::err_asm_unknown_register_name) << Label;
}
NewVD->addAttr(::new (Context) AsmLabelAttr(SE->getStrTokenLoc(0),
Added: cfe/trunk/test/CodeGen/named_reg_global.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/named_reg_global.c?rev=209149&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/named_reg_global.c (added)
+++ cfe/trunk/test/CodeGen/named_reg_global.c Mon May 19 13:15:42 2014
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -S -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple aarch64-linux-gnu -S -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple arm64-linux-gnu -S -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple armv7-linux-gnu -S -emit-llvm %s -o - | FileCheck %s
+
+register unsigned long current_stack_pointer asm("sp");
+
+// CHECK: define{{.*}} i[[bits:[0-9]+]] @get_stack_pointer_addr()
+// CHECK: [[ret:%[0-9]+]] = call i[[bits]] @llvm.read_register.i[[bits]](metadata !0)
+// CHECK: ret i[[bits]] [[ret]]
+unsigned long get_stack_pointer_addr() {
+ return current_stack_pointer;
+}
+// CHECK: declare{{.*}} i[[bits]] @llvm.read_register.i[[bits]](metadata)
+
+// CHECK: define{{.*}} void @set_stack_pointer_addr(i[[bits]] %addr) #0 {
+// CHECK: [[sto:%[0-9]+]] = load i[[bits]]* %addr
+// CHECK: call void @llvm.write_register.i[[bits]](metadata !0, i[[bits]] [[sto]])
+// CHECK: ret void
+void set_stack_pointer_addr(unsigned long addr) {
+ current_stack_pointer = addr;
+}
+// CHECK: declare{{.*}} void @llvm.write_register.i[[bits]](metadata, i[[bits]])
+
+// CHECK: !llvm.named.register.sp = !{!0}
+// CHECK: !0 = metadata !{metadata !"sp"}
Modified: cfe/trunk/test/Sema/asm.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/asm.c?rev=209149&r1=209148&r2=209149&view=diff
==============================================================================
--- cfe/trunk/test/Sema/asm.c (original)
+++ cfe/trunk/test/Sema/asm.c Mon May 19 13:15:42 2014
@@ -95,8 +95,6 @@ void test9(int i) {
asm("" : [foo] "=r" (i), "=r"(i) : "[foo]1"(i)); // expected-error{{invalid input constraint '[foo]1' in asm}}
}
-register int g asm("dx"); // expected-error{{global register variables are not supported}}
-
void test10(void){
static int g asm ("g_asm") = 0;
extern int gg asm ("gg_asm");
Modified: cfe/trunk/test/Sema/decl-invalid.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/decl-invalid.c?rev=209149&r1=209148&r2=209149&view=diff
==============================================================================
--- cfe/trunk/test/Sema/decl-invalid.c (original)
+++ cfe/trunk/test/Sema/decl-invalid.c Mon May 19 13:15:42 2014
@@ -24,5 +24,4 @@ I; // expected-warning {{declaration doe
// rdar://6880449
register int test1; // expected-error {{illegal storage class on file-scoped variable}}
-register int test2 __asm__("edi"); // expected-error {{global register variables are not supported}}
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