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[PPC] Use alias symbols in address computation. 

This seems to match what gcc does for ppc and what every other llvm
backend does.

This is a fixed version of r209638. The difference is to avoid any change
in behavior for functions. The logic for using constant pools for function
addresseses is spread over a few places and we have to keep them in sync.

llvm-svn: 209821
This commit is contained in:
Rafael Espindola 2014-05-29 15:41:38 +00:00
parent 1613650e90
commit 04902862a8
3 changed files with 48 additions and 34 deletions
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37
llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
View File

@ -380,15 +380,12 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
bool IsAvailExt = false;
if (MO.isGlobal()) {
const GlobalValue *GValue = MO.getGlobal();
const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
const GlobalValue *RealGValue = GAlias ? GAlias->getAliasee() : GValue;
MOSymbol = getSymbol(RealGValue);
const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
IsExternal = GVar && !GVar->hasInitializer();
IsCommon = GVar && RealGValue->hasCommonLinkage();
IsFunction = !GVar;
IsAvailExt = GVar && RealGValue->hasAvailableExternallyLinkage();
const GlobalValue *GV = MO.getGlobal();
MOSymbol = getSymbol(GV);
IsExternal = GV->isDeclaration();
IsCommon = GV->hasCommonLinkage();
IsFunction = GV->getType()->getElementType()->isFunctionTy();
IsAvailExt = GV->hasAvailableExternallyLinkage();
} else if (MO.isCPI())
MOSymbol = GetCPISymbol(MO.getIndex());
else if (MO.isJTI())
@ -427,13 +424,10 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
}
else if (MO.isGlobal()) {
const GlobalValue *GValue = MO.getGlobal();
const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
const GlobalValue *RealGValue = GAlias ? GAlias->getAliasee() : GValue;
MOSymbol = getSymbol(RealGValue);
const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
if (!GVar || !GVar->hasInitializer() || RealGValue->hasCommonLinkage() ||
RealGValue->hasAvailableExternallyLinkage() ||
MOSymbol = getSymbol(GValue);
if (GValue->getType()->getElementType()->isFunctionTy() ||
GValue->isDeclaration() || GValue->hasCommonLinkage() ||
GValue->hasAvailableExternallyLinkage() ||
TM.getCodeModel() == CodeModel::Large)
MOSymbol = lookUpOrCreateTOCEntry(MOSymbol);
}
@ -460,13 +454,10 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
bool IsFunction = false;
if (MO.isGlobal()) {
const GlobalValue *GValue = MO.getGlobal();
const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
const GlobalValue *RealGValue = GAlias ? GAlias->getAliasee() : GValue;
MOSymbol = getSymbol(RealGValue);
const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
IsExternal = GVar && !GVar->hasInitializer();
IsFunction = !GVar;
const GlobalValue *GV = MO.getGlobal();
MOSymbol = getSymbol(GV);
IsExternal = GV->isDeclaration();
IsFunction = GV->getType()->getElementType()->isFunctionTy();
} else if (MO.isCPI())
MOSymbol = GetCPISymbol(MO.getIndex());

14
llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
View File

@ -1472,17 +1472,9 @@ SDNode *PPCDAGToDAGISel::Select(SDNode *N) {
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(GA)) {
const GlobalValue *GValue = G->getGlobal();
const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
const GlobalValue *RealGValue = GAlias ? GAlias->getAliasee() : GValue;
const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
assert((GVar || isa<Function>(RealGValue)) &&
"Unexpected global value subclass!");
// An external variable is one without an initializer. For these,
// for variables with common linkage, and for Functions, generate
// the LDtocL form.
if (!GVar || !GVar->hasInitializer() || RealGValue->hasCommonLinkage() ||
RealGValue->hasAvailableExternallyLinkage())
if (GValue->getType()->getElementType()->isFunctionTy() ||
GValue->isDeclaration() || GValue->hasCommonLinkage() ||
GValue->hasAvailableExternallyLinkage())
return CurDAG->getMachineNode(PPC::LDtocL, dl, MVT::i64, GA,
SDValue(Tmp, 0));
}

31
llvm/test/CodeGen/PowerPC/alias.ll Normal file
View File

@ -0,0 +1,31 @@
; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -code-model=medium| FileCheck --check-prefix=CHECK --check-prefix=MEDIUM %s
; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -code-model=large | FileCheck --check-prefix=CHECK --check-prefix=LARGE %s
@foo = global i32 42
@fooa = alias i32* @foo
@foo2 = global i64 42
@foo2a = alias i64* @foo2
; CHECK-LABEL: bar:
define i32 @bar() {
; MEDIUM: addis 3, 2, fooa@toc@ha
; LARGE: addis 3, 2, .LC1@toc@ha
%a = load i32* @fooa
ret i32 %a
}
; CHECK-LABEL: bar2:
define i64 @bar2() {
; MEDIUM: addis 3, 2, foo2a@toc@ha
; MEDIUM: addi 3, 3, foo2a@toc@l
; LARGE: addis 3, 2, .LC3@toc@ha
%a = load i64* @foo2a
ret i64 %a
}
; LARGE: .LC1:
; LARGE-NEXT: .tc fooa[TC],fooa
; LARGE: .LC3:
; LARGE-NEXT: .tc foo2a[TC],foo2a