[llvm] r311353 - [PPC] Refine checks for emiting TOC restore nop and tail-call eligibility.
Sean Fertile via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 21 10:35:32 PDT 2017
Author: sfertile
Date: Mon Aug 21 10:35:32 2017
New Revision: 311353
URL: http://llvm.org/viewvc/llvm-project?rev=311353&view=rev
Log:
[PPC] Refine checks for emiting TOC restore nop and tail-call eligibility.
For the medium and large code models we only need to check if a call crosses
dso-boundaries when considering tail-call elgibility.
Differential Revision: https://reviews.llvm.org/D34245
Modified:
llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
llvm/trunk/test/CodeGen/PowerPC/ppc64-blnop.ll
llvm/trunk/test/CodeGen/PowerPC/ppc64-calls.ll
llvm/trunk/test/CodeGen/PowerPC/ppc64-sibcall.ll
Modified: llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp?rev=311353&r1=311352&r2=311353&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp Mon Aug 21 10:35:32 2017
@@ -4255,13 +4255,25 @@ static int CalculateTailCallSPDiff(Selec
static bool isFunctionGlobalAddress(SDValue Callee);
static bool
-resideInSameSection(const Function *Caller, SDValue Callee,
+callsShareTOCBase(const Function *Caller, SDValue Callee,
const TargetMachine &TM) {
// If !G, Callee can be an external symbol.
GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee);
if (!G)
return false;
+ // The medium and large code models are expected to provide a sufficiently
+ // large TOC to provide all data addressing needs of a module with a
+ // single TOC. Since each module will be addressed with a single TOC then we
+ // only need to check that caller and callee don't cross dso boundaries.
+ if (CodeModel::Medium == TM.getCodeModel() ||
+ CodeModel::Large == TM.getCodeModel())
+ return TM.shouldAssumeDSOLocal(*Caller->getParent(), G->getGlobal());
+
+ // Otherwise we need to ensure callee and caller are in the same section,
+ // since the linker may allocate multiple TOCs, and we don't know which
+ // sections will belong to the same TOC base.
+
const GlobalValue *GV = G->getGlobal();
if (!GV->isStrongDefinitionForLinker())
return false;
@@ -4410,11 +4422,10 @@ PPCTargetLowering::IsEligibleForTailCall
!isa<ExternalSymbolSDNode>(Callee))
return false;
- // Check if Callee resides in the same section, because for now, PPC64 SVR4
- // ABI (ELFv1/ELFv2) doesn't allow tail calls to a symbol resides in another
- // section.
+ // If the caller and callee potentially have different TOC bases then we
+ // cannot tail call since we need to restore the TOC pointer after the call.
// ref: https://bugzilla.mozilla.org/show_bug.cgi?id=973977
- if (!resideInSameSection(MF.getFunction(), Callee, getTargetMachine()))
+ if (!callsShareTOCBase(MF.getFunction(), Callee, getTargetMachine()))
return false;
// TCO allows altering callee ABI, so we don't have to check further.
@@ -4996,7 +5007,7 @@ SDValue PPCTargetLowering::FinishCall(
// any other variadic arguments).
Ops.insert(std::next(Ops.begin()), AddTOC);
} else if (CallOpc == PPCISD::CALL &&
- !resideInSameSection(MF.getFunction(), Callee, DAG.getTarget())) {
+ !callsShareTOCBase(MF.getFunction(), Callee, DAG.getTarget())) {
// Otherwise insert NOP for non-local calls.
CallOpc = PPCISD::CALL_NOP;
}
Modified: llvm/trunk/test/CodeGen/PowerPC/ppc64-blnop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/ppc64-blnop.ll?rev=311353&r1=311352&r2=311353&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/ppc64-blnop.ll (original)
+++ llvm/trunk/test/CodeGen/PowerPC/ppc64-blnop.ll Mon Aug 21 10:35:32 2017
@@ -5,6 +5,8 @@
; RUN: llc < %s -function-sections -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu | FileCheck %s -check-prefix=CHECK-FS
; RUN: llc < %s -relocation-model=pic -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu | FileCheck %s
; RUN: llc < %s -function-sections -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu | FileCheck %s -check-prefix=CHECK-FS
+; RUN: llc < %s -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu \
+; RUN: -code-model=small -mcpu=pwr8 | FileCheck %s -check-prefix=SCM
%class.T = type { [2 x i8] }
@@ -74,7 +76,11 @@ define void @wo_hcaller(%class.T* %this,
; CHECK-LABEL: wo_hcaller:
; CHECK: bl wo_hcallee
-; CHECK-NEXT: nop
+; CHECK-NOT: nop
+
+; SCM-LABEL: wo_hcaller:
+; SCM: bl wo_hcallee
+; SCM-NEXT: nop
}
define weak_odr protected void @wo_pcallee(%class.T* %this, i8* %c) { ret void }
@@ -84,7 +90,11 @@ define void @wo_pcaller(%class.T* %this,
; CHECK-LABEL: wo_pcaller:
; CHECK: bl wo_pcallee
-; CHECK-NEXT: nop
+; CHECK-NOT: nop
+
+; SCM-LABEL: wo_pcaller:
+; SCM: bl wo_pcallee
+; SCM-NEXT: nop
}
define weak_odr void @wo_callee(%class.T* %this, i8* %c) { ret void }
@@ -104,7 +114,11 @@ define void @w_pcaller(i8* %ptr) {
; CHECK-LABEL: w_pcaller:
; CHECK: bl w_pcallee
-; CHECK-NEXT: nop
+; CHECK-NOT: nop
+
+; SCM-LABEL: w_pcaller:
+; SCM: bl w_pcallee
+; SCM-NEXT: nop
}
define weak hidden void @w_hcallee(i8* %ptr) { ret void }
@@ -114,7 +128,11 @@ define void @w_hcaller(i8* %ptr) {
; CHECK-LABEL: w_hcaller:
; CHECK: bl w_hcallee
-; CHECK-NEXT: nop
+; CHECK-NOT: nop
+
+; SCM-LABEL: w_hcaller:
+; SCM: bl w_hcallee
+; SCM-NEXT: nop
}
define weak void @w_callee(i8* %ptr) { ret void }
Modified: llvm/trunk/test/CodeGen/PowerPC/ppc64-calls.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/ppc64-calls.ll?rev=311353&r1=311352&r2=311353&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/ppc64-calls.ll (original)
+++ llvm/trunk/test/CodeGen/PowerPC/ppc64-calls.ll Mon Aug 21 10:35:32 2017
@@ -1,4 +1,6 @@
; RUN: llc -relocation-model=static -verify-machineinstrs < %s -mcpu=pwr7 | FileCheck %s
+; RUN: llc -relocation-model=static -verify-machineinstrs < %s -code-model=small -mcpu=pwr7 | FileCheck %s -check-prefix=SCM
+
target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v128:128:128-n32:64"
target triple = "powerpc64-unknown-linux-gnu"
@@ -21,13 +23,22 @@ define void @test_direct() nounwind read
ret void
}
-; Calls to weak function requires a TOC restore 'nop' because they
-; may be overridden in a different module.
+; Calls to weak function requires a TOC restore 'nop' with the small codemodel
+; because the definition that gets choosen at link time may come from a
+; different section even though we have seen a weak definition in the same
+; section at compile time.
+; With large and medium codemodels no TOC restore is needed, since we know
+; whichever definition is choosen it resides within the same DSO boundaries and
+; therefore shares the same TOC.
define void @test_weak() nounwind readnone {
-; CHECK-LABEL: test_weak:
tail call void @foo_weak() nounwind
-; CHECK: bl foo
-; CHECK-NEXT: nop
+; CHECK-LABEL: test_weak:
+; CHECK: b foo_weak
+; CHECK-NOT: nop
+
+; SCM-LABEL: test_weak:
+; SCM: bl foo_weak
+; SCM-NEXT: nop
ret void
}
Modified: llvm/trunk/test/CodeGen/PowerPC/ppc64-sibcall.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/ppc64-sibcall.ll?rev=311353&r1=311352&r2=311353&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/ppc64-sibcall.ll (original)
+++ llvm/trunk/test/CodeGen/PowerPC/ppc64-sibcall.ll Mon Aug 21 10:35:32 2017
@@ -1,6 +1,7 @@
; RUN: llc < %s -relocation-model=static -O1 -disable-ppc-sco=false -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu | FileCheck %s -check-prefix=CHECK-SCO
; RUN: llc < %s -relocation-model=static -O1 -disable-ppc-sco=false -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr8 | FileCheck %s -check-prefix=CHECK-SCO-HASQPX
; RUN: llc < %s -relocation-model=static -O1 -disable-ppc-sco=false -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu -mcpu=pwr8 | FileCheck %s -check-prefix=CHECK-SCO-HASQPX
+; RUN: llc < %s -relocation-model=static -O1 -disable-ppc-sco=false -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu -mcpu=pwr8 -code-model=small | FileCheck %s -check-prefix=SCM
; No combination of "powerpc64le-unknown-linux-gnu" + "CHECK-SCO", because
; only Power8 (and later) fully support LE.
@@ -142,7 +143,10 @@ define void @wo_hcaller(%class.T* %this,
ret void
; CHECK-SCO-LABEL: wo_hcaller:
-; CHECK-SCO: bl wo_hcallee
+; CHECK-SCO: b wo_hcallee
+
+; SCM-LABEL: wo_hcaller:
+; SCM: bl wo_hcallee
}
define weak_odr protected void @wo_pcallee(%class.T* %this, i8* %c) { ret void }
@@ -151,7 +155,10 @@ define void @wo_pcaller(%class.T* %this,
ret void
; CHECK-SCO-LABEL: wo_pcaller:
-; CHECK-SCO: bl wo_pcallee
+; CHECK-SCO: b wo_pcallee
+
+; SCM-LABEL: wo_pcaller:
+; SCM: bl wo_pcallee
}
define weak_odr void @wo_callee(%class.T* %this, i8* %c) { ret void }
@@ -160,7 +167,10 @@ define void @wo_caller(%class.T* %this,
ret void
; CHECK-SCO-LABEL: wo_caller:
-; CHECK-SCO: bl wo_callee
+; CHECK-SCO: b wo_callee
+
+; SCM-LABEL: wo_caller:
+; SCM: bl wo_callee
}
define weak protected void @w_pcallee(i8* %ptr) { ret void }
@@ -169,7 +179,10 @@ define void @w_pcaller(i8* %ptr) {
ret void
; CHECK-SCO-LABEL: w_pcaller:
-; CHECK-SCO: bl w_pcallee
+; CHECK-SCO: b w_pcallee
+
+; SCM-LABEL: w_pcaller:
+; SCM: bl w_pcallee
}
define weak hidden void @w_hcallee(i8* %ptr) { ret void }
@@ -178,7 +191,10 @@ define void @w_hcaller(i8* %ptr) {
ret void
; CHECK-SCO-LABEL: w_hcaller:
-; CHECK-SCO: bl w_hcallee
+; CHECK-SCO: b w_hcallee
+
+; SCM-LABEL: w_hcaller:
+; SCM: bl w_hcallee
}
define weak void @w_callee(i8* %ptr) { ret void }
@@ -187,7 +203,10 @@ define void @w_caller(i8* %ptr) {
ret void
; CHECK-SCO-LABEL: w_caller:
-; CHECK-SCO: bl w_callee
+; CHECK-SCO: b w_callee
+
+; SCM-LABEL: w_caller:
+; SCM: bl w_callee
}
%struct.byvalTest = type { [8 x i8] }
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