From: Ulrich Weigand Date: Wed, 13 Jan 2016 13:12:23 +0000 (+0000) Subject: [PowerPC] Fix large code model with the ELFv2 ABI X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=dc8dfe1b86ab88d4db816714fa38951cd1b843d5 [PowerPC] Fix large code model with the ELFv2 ABI The global entry point prologue currently assumes that the TOC associated with a function is less than 2GB away from the function entry point. This is always true when using the medium or small code model, but may not be the case when using the large code model. This patch adds a new variant of the ELFv2 global entry point prologue that lifts the 2GB restriction when building with -mcmodel=large. This works by emitting a quadword containing the distance from the function entry point to its associated TOC immediately before the entry point, and then using a prologue like: ld r2,-8(r12) add r2,r2,r12 Since creation of the entry point prologue is now split across two separate routines (PPCLinuxAsmPrinter::EmitFunctionEntryLabel emits the data word, PPCLinuxAsmPrinter::EmitFunctionBodyStart the prolog code), I've switched to using named labels instead of just temporaries to indicate the locations of the global and local entry points and the new TOC offset data word. These names are provided by new routines in PPCFunctionInfo modeled after the existing PPCFunctionInfo::getPICOffsetSymbol. Note that a corresponding change was committed to GCC here: https://gcc.gnu.org/ml/gcc-patches/2015-12/msg00355.html Reviewers: hfinkel Differential Revision: http://reviews.llvm.org/D15500 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257597 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp index 9a63c14b505..ec354c209ca 100644 --- a/lib/Target/PowerPC/PPCAsmPrinter.cpp +++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp @@ -1092,8 +1092,28 @@ void PPCLinuxAsmPrinter::EmitFunctionEntryLabel() { } // ELFv2 ABI - Normal entry label. - if (Subtarget->isELFv2ABI()) + if (Subtarget->isELFv2ABI()) { + // In the Large code model, we allow arbitrary displacements between + // the text section and its associated TOC section. We place the + // full 8-byte offset to the TOC in memory immediatedly preceding + // the function global entry point. + if (TM.getCodeModel() == CodeModel::Large + && !MF->getRegInfo().use_empty(PPC::X2)) { + const PPCFunctionInfo *PPCFI = MF->getInfo(); + + MCSymbol *TOCSymbol = OutContext.getOrCreateSymbol(StringRef(".TOC.")); + MCSymbol *GlobalEPSymbol = PPCFI->getGlobalEPSymbol(); + const MCExpr *TOCDeltaExpr = + MCBinaryExpr::createSub(MCSymbolRefExpr::create(TOCSymbol, OutContext), + MCSymbolRefExpr::create(GlobalEPSymbol, + OutContext), + OutContext); + + OutStreamer->EmitLabel(PPCFI->getTOCOffsetSymbol()); + OutStreamer->EmitValue(TOCDeltaExpr, 8); + } return AsmPrinter::EmitFunctionEntryLabel(); + } // Emit an official procedure descriptor. MCSectionSubPair Current = OutStreamer->getCurrentSection(); @@ -1160,10 +1180,25 @@ void PPCLinuxAsmPrinter::EmitFunctionBodyStart() { // thus emit a prefix sequence along the following lines: // // func: + // .Lfunc_gepNN: + // # global entry point + // addis r2,r12,(.TOC.-.Lfunc_gepNN)@ha + // addi r2,r2,(.TOC.-.Lfunc_gepNN)@l + // .Lfunc_lepNN: + // .localentry func, .Lfunc_lepNN-.Lfunc_gepNN + // # local entry point, followed by function body + // + // For the Large code model, we create + // + // .Lfunc_tocNN: + // .quad .TOC.-.Lfunc_gepNN # done by EmitFunctionEntryLabel + // func: + // .Lfunc_gepNN: // # global entry point - // addis r2,r12,(.TOC.-func)@ha - // addi r2,r2,(.TOC.-func)@l - // .localentry func, .-func + // ld r2,.Lfunc_tocNN-.Lfunc_gepNN(r12) + // add r2,r2,r12 + // .Lfunc_lepNN: + // .localentry func, .Lfunc_lepNN-.Lfunc_gepNN // # local entry point, followed by function body // // This ensures we have r2 set up correctly while executing the function @@ -1171,32 +1206,49 @@ void PPCLinuxAsmPrinter::EmitFunctionBodyStart() { if (Subtarget->isELFv2ABI() // Only do all that if the function uses r2 in the first place. && !MF->getRegInfo().use_empty(PPC::X2)) { + const PPCFunctionInfo *PPCFI = MF->getInfo(); - MCSymbol *GlobalEntryLabel = OutContext.createTempSymbol(); + MCSymbol *GlobalEntryLabel = PPCFI->getGlobalEPSymbol(); OutStreamer->EmitLabel(GlobalEntryLabel); const MCSymbolRefExpr *GlobalEntryLabelExp = MCSymbolRefExpr::create(GlobalEntryLabel, OutContext); - MCSymbol *TOCSymbol = OutContext.getOrCreateSymbol(StringRef(".TOC.")); - const MCExpr *TOCDeltaExpr = - MCBinaryExpr::createSub(MCSymbolRefExpr::create(TOCSymbol, OutContext), - GlobalEntryLabelExp, OutContext); + if (TM.getCodeModel() != CodeModel::Large) { + MCSymbol *TOCSymbol = OutContext.getOrCreateSymbol(StringRef(".TOC.")); + const MCExpr *TOCDeltaExpr = + MCBinaryExpr::createSub(MCSymbolRefExpr::create(TOCSymbol, OutContext), + GlobalEntryLabelExp, OutContext); - const MCExpr *TOCDeltaHi = - PPCMCExpr::createHa(TOCDeltaExpr, false, OutContext); - EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::ADDIS) - .addReg(PPC::X2) - .addReg(PPC::X12) - .addExpr(TOCDeltaHi)); - - const MCExpr *TOCDeltaLo = - PPCMCExpr::createLo(TOCDeltaExpr, false, OutContext); - EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::ADDI) - .addReg(PPC::X2) - .addReg(PPC::X2) - .addExpr(TOCDeltaLo)); - - MCSymbol *LocalEntryLabel = OutContext.createTempSymbol(); + const MCExpr *TOCDeltaHi = + PPCMCExpr::createHa(TOCDeltaExpr, false, OutContext); + EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::ADDIS) + .addReg(PPC::X2) + .addReg(PPC::X12) + .addExpr(TOCDeltaHi)); + + const MCExpr *TOCDeltaLo = + PPCMCExpr::createLo(TOCDeltaExpr, false, OutContext); + EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::ADDI) + .addReg(PPC::X2) + .addReg(PPC::X2) + .addExpr(TOCDeltaLo)); + } else { + MCSymbol *TOCOffset = PPCFI->getTOCOffsetSymbol(); + const MCExpr *TOCOffsetDeltaExpr = + MCBinaryExpr::createSub(MCSymbolRefExpr::create(TOCOffset, OutContext), + GlobalEntryLabelExp, OutContext); + + EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::LD) + .addReg(PPC::X2) + .addExpr(TOCOffsetDeltaExpr) + .addReg(PPC::X12)); + EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::ADD8) + .addReg(PPC::X2) + .addReg(PPC::X2) + .addReg(PPC::X12)); + } + + MCSymbol *LocalEntryLabel = PPCFI->getLocalEPSymbol(); OutStreamer->EmitLabel(LocalEntryLabel); const MCSymbolRefExpr *LocalEntryLabelExp = MCSymbolRefExpr::create(LocalEntryLabel, OutContext); diff --git a/lib/Target/PowerPC/PPCMachineFunctionInfo.cpp b/lib/Target/PowerPC/PPCMachineFunctionInfo.cpp index 95f163153c7..9d91e31165d 100644 --- a/lib/Target/PowerPC/PPCMachineFunctionInfo.cpp +++ b/lib/Target/PowerPC/PPCMachineFunctionInfo.cpp @@ -23,3 +23,24 @@ MCSymbol *PPCFunctionInfo::getPICOffsetSymbol() const { Twine(MF.getFunctionNumber()) + "$poff"); } + +MCSymbol *PPCFunctionInfo::getGlobalEPSymbol() const { + const DataLayout &DL = MF.getDataLayout(); + return MF.getContext().getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) + + "func_gep" + + Twine(MF.getFunctionNumber())); +} + +MCSymbol *PPCFunctionInfo::getLocalEPSymbol() const { + const DataLayout &DL = MF.getDataLayout(); + return MF.getContext().getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) + + "func_lep" + + Twine(MF.getFunctionNumber())); +} + +MCSymbol *PPCFunctionInfo::getTOCOffsetSymbol() const { + const DataLayout &DL = MF.getDataLayout(); + return MF.getContext().getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) + + "func_toc" + + Twine(MF.getFunctionNumber())); +} diff --git a/lib/Target/PowerPC/PPCMachineFunctionInfo.h b/lib/Target/PowerPC/PPCMachineFunctionInfo.h index 607cdf612ee..10a8ce068d4 100644 --- a/lib/Target/PowerPC/PPCMachineFunctionInfo.h +++ b/lib/Target/PowerPC/PPCMachineFunctionInfo.h @@ -197,6 +197,10 @@ public: bool usesPICBase() const { return UsesPICBase; } MCSymbol *getPICOffsetSymbol() const; + + MCSymbol *getGlobalEPSymbol() const; + MCSymbol *getLocalEPSymbol() const; + MCSymbol *getTOCOffsetSymbol() const; }; } // end of namespace llvm diff --git a/test/CodeGen/PowerPC/ppc64le-localentry-large.ll b/test/CodeGen/PowerPC/ppc64le-localentry-large.ll new file mode 100644 index 00000000000..4cf1b5a233d --- /dev/null +++ b/test/CodeGen/PowerPC/ppc64le-localentry-large.ll @@ -0,0 +1,27 @@ +; RUN: llc -march=ppc64le -code-model=large < %s | FileCheck %s + +target datalayout = "e-m:e-i64:64-n32:64" +target triple = "powerpc64le-unknown-linux-gnu" + +@number64 = global i64 10, align 8 + +; CHECK: .abiversion 2 + +define i64 @use_toc(i64 %a) nounwind { +entry: +; CHECK: .Lfunc_toc[[FN:[0-9]+]]: +; CHECK-NEXT: .quad .TOC.-.Lfunc_gep[[FN]] +; CHECK: use_toc: +; CHECK-NEXT: .L{{.*}}: +; CHECK-NEXT: .Lfunc_gep[[FN]]: +; CHECK-NEXT: ld 2, .Lfunc_toc[[FN]]-.Lfunc_gep[[FN]](12) +; CHECK-NEXT: add 2, 2, 12 +; CHECK-NEXT: .Lfunc_lep[[FN]]: +; CHECK-NEXT: .localentry use_toc, .Lfunc_lep[[FN]]-.Lfunc_gep[[FN]] +; CHECK-NEXT: %entry + %0 = load i64, i64* @number64, align 8 + %cmp = icmp eq i64 %0, %a + %conv1 = zext i1 %cmp to i64 + ret i64 %conv1 +} + diff --git a/test/CodeGen/PowerPC/ppc64le-localentry.ll b/test/CodeGen/PowerPC/ppc64le-localentry.ll index be64f115176..45cae6b17bc 100644 --- a/test/CodeGen/PowerPC/ppc64le-localentry.ll +++ b/test/CodeGen/PowerPC/ppc64le-localentry.ll @@ -17,11 +17,11 @@ define i64 @use_toc(i64 %a) nounwind { entry: ; CHECK-LABEL: @use_toc ; CHECK-NEXT: .L{{.*}}: -; CHECK-NEXT: .Ltmp[[TMP1:[0-9]+]]: -; CHECK-NEXT: addis 2, 12, .TOC.-.Ltmp[[TMP1]]@ha -; CHECK-NEXT: addi 2, 2, .TOC.-.Ltmp[[TMP1]]@l -; CHECK-NEXT: .Ltmp[[TMP2:[0-9]+]]: -; CHECK-NEXT: .localentry use_toc, .Ltmp[[TMP2]]-.Ltmp[[TMP1]] +; CHECK-NEXT: .Lfunc_gep[[FN:[0-9]+]]: +; CHECK-NEXT: addis 2, 12, .TOC.-.Lfunc_gep[[FN]]@ha +; CHECK-NEXT: addi 2, 2, .TOC.-.Lfunc_gep[[FN]]@l +; CHECK-NEXT: .Lfunc_lep[[FN]]: +; CHECK-NEXT: .localentry use_toc, .Lfunc_lep[[FN]]-.Lfunc_gep[[FN]] ; CHECK-NEXT: %entry %0 = load i64, i64* @number64, align 8 %cmp = icmp eq i64 %0, %a @@ -34,11 +34,11 @@ define void @use_toc_implicit() nounwind { entry: ; CHECK-LABEL: @use_toc_implicit ; CHECK-NEXT: .L{{.*}}: -; CHECK-NEXT: .Ltmp[[TMP1:[0-9]+]]: -; CHECK-NEXT: addis 2, 12, .TOC.-.Ltmp[[TMP1]]@ha -; CHECK-NEXT: addi 2, 2, .TOC.-.Ltmp[[TMP1]]@l -; CHECK-NEXT: .Ltmp[[TMP2:[0-9]+]]: -; CHECK-NEXT: .localentry use_toc_implicit, .Ltmp[[TMP2]]-.Ltmp[[TMP1]] +; CHECK-NEXT: .Lfunc_gep[[FN:[0-9]+]]: +; CHECK-NEXT: addis 2, 12, .TOC.-.Lfunc_gep[[FN]]@ha +; CHECK-NEXT: addi 2, 2, .TOC.-.Lfunc_gep[[FN]]@l +; CHECK-NEXT: .Lfunc_lep[[FN]]: +; CHECK-NEXT: .localentry use_toc_implicit, .Lfunc_lep[[FN]]-.Lfunc_gep[[FN]] ; CHECK-NEXT: %entry call void @callee() ret void