From 74fce4a7b86e45b6822361918260b83b59a4fe39 Mon Sep 17 00:00:00 2001 From: Stefan Pintilie Date: Tue, 21 Jul 2020 12:54:48 -0500 Subject: [PATCH] [PowerPC] Extend .reloc directive on PowerPC When the compiler generates a GOT indirect load it must generate two loads. One that loads the address of the element from the GOT and a second to load the actual element based on the address just loaded from the GOT. However, the linker can optimize these two loads into one load if it knows that it is safe to do so. The compiler can tell the linker that the optimization is safe by using the R_PPC64_PCREL_OPT relocation. This patch extends the .reloc directive to allow the following setup pld 3, vec@got@pcrel(0), 1 .Lpcrel1=.-8 ... More instructions possible here ... .reloc .Lpcrel1,R_PPC64_PCREL_OPT,.-.Lpcrel1 lwa 3, 4(3) Reviewers: nemanjai, lei, hfinkel, sfertile, efriedma, tstellar, grosbach, MaskRay Reviewed By: nemanjai, MaskRay Differential Revision: https://reviews.llvm.org/D79625 --- .../llvm/BinaryFormat/ELFRelocs/PowerPC64.def | 2 + lib/MC/MCObjectStreamer.cpp | 75 +++- test/MC/PowerPC/ppc64-reloc-directive-pcrel.s | 401 ++++++++++++++++++ 3 files changed, 475 insertions(+), 3 deletions(-) create mode 100644 test/MC/PowerPC/ppc64-reloc-directive-pcrel.s diff --git a/include/llvm/BinaryFormat/ELFRelocs/PowerPC64.def b/include/llvm/BinaryFormat/ELFRelocs/PowerPC64.def index e28c9caaefa..ddcafa2065b 100644 --- a/include/llvm/BinaryFormat/ELFRelocs/PowerPC64.def +++ b/include/llvm/BinaryFormat/ELFRelocs/PowerPC64.def @@ -97,6 +97,7 @@ #undef R_PPC64_DTPREL16_HIGH #undef R_PPC64_DTPREL16_HIGHA #undef R_PPC64_REL24_NOTOC +#undef R_PPC64_PCREL_OPT #undef R_PPC64_PCREL34 #undef R_PPC64_GOT_PCREL34 #undef R_PPC64_IRELATIVE @@ -194,6 +195,7 @@ ELF_RELOC(R_PPC64_TPREL16_HIGHA, 113) ELF_RELOC(R_PPC64_DTPREL16_HIGH, 114) ELF_RELOC(R_PPC64_DTPREL16_HIGHA, 115) ELF_RELOC(R_PPC64_REL24_NOTOC, 116) +ELF_RELOC(R_PPC64_PCREL_OPT, 123) ELF_RELOC(R_PPC64_PCREL34, 132) ELF_RELOC(R_PPC64_GOT_PCREL34, 133) ELF_RELOC(R_PPC64_IRELATIVE, 248) diff --git a/lib/MC/MCObjectStreamer.cpp b/lib/MC/MCObjectStreamer.cpp index e39c4a03bc1..78ee215b59a 100644 --- a/lib/MC/MCObjectStreamer.cpp +++ b/lib/MC/MCObjectStreamer.cpp @@ -665,6 +665,68 @@ void MCObjectStreamer::emitGPRel64Value(const MCExpr *Value) { DF->getContents().resize(DF->getContents().size() + 8, 0); } +static Optional> +getOffsetAndDataFragment(const MCSymbol &Symbol, uint32_t &RelocOffset, + MCDataFragment *&DF) { + if (Symbol.isVariable()) { + const MCExpr *SymbolExpr = Symbol.getVariableValue(); + MCValue OffsetVal; + if(!SymbolExpr->evaluateAsRelocatable(OffsetVal, nullptr, nullptr)) + return std::make_pair(false, + std::string("symbol in .reloc offset is not " + "relocatable")); + if (OffsetVal.isAbsolute()) { + RelocOffset = OffsetVal.getConstant(); + MCFragment *Fragment = Symbol.getFragment(); + // FIXME Support symbols with no DF. For example: + // .reloc .data, ENUM_VALUE, + if (!Fragment || Fragment->getKind() != MCFragment::FT_Data) + return std::make_pair(false, + std::string("symbol in offset has no data " + "fragment")); + DF = cast(Fragment); + return None; + } + + if (OffsetVal.getSymB()) + return std::make_pair(false, + std::string(".reloc symbol offset is not " + "representable")); + + const MCSymbolRefExpr &SRE = cast(*OffsetVal.getSymA()); + if (!SRE.getSymbol().isDefined()) + return std::make_pair(false, + std::string("symbol used in the .reloc offset is " + "not defined")); + + if (SRE.getSymbol().isVariable()) + return std::make_pair(false, + std::string("symbol used in the .reloc offset is " + "variable")); + + MCFragment *Fragment = SRE.getSymbol().getFragment(); + // FIXME Support symbols with no DF. For example: + // .reloc .data, ENUM_VALUE, + if (!Fragment || Fragment->getKind() != MCFragment::FT_Data) + return std::make_pair(false, + std::string("symbol in offset has no data " + "fragment")); + RelocOffset = SRE.getSymbol().getOffset() + OffsetVal.getConstant(); + DF = cast(Fragment); + } else { + RelocOffset = Symbol.getOffset(); + MCFragment *Fragment = Symbol.getFragment(); + // FIXME Support symbols with no DF. For example: + // .reloc .data, ENUM_VALUE, + if (!Fragment || Fragment->getKind() != MCFragment::FT_Data) + return std::make_pair(false, + std::string("symbol in offset has no data " + "fragment")); + DF = cast(Fragment); + } + return None; +} + Optional> MCObjectStreamer::emitRelocDirective(const MCExpr &Offset, StringRef Name, const MCExpr *Expr, SMLoc Loc, @@ -698,10 +760,17 @@ MCObjectStreamer::emitRelocDirective(const MCExpr &Offset, StringRef Name, std::string(".reloc offset is not representable")); const MCSymbolRefExpr &SRE = cast(*OffsetVal.getSymA()); - if (SRE.getSymbol().isDefined()) { - // FIXME SRE.getSymbol() may not be relative to DF. + const MCSymbol &Symbol = SRE.getSymbol(); + if (Symbol.isDefined()) { + uint32_t SymbolOffset = 0; + Optional> Error; + Error = getOffsetAndDataFragment(Symbol, SymbolOffset, DF); + + if (Error != None) + return Error; + DF->getFixups().push_back( - MCFixup::create(SRE.getSymbol().getOffset() + OffsetVal.getConstant(), + MCFixup::create(SymbolOffset + OffsetVal.getConstant(), Expr, Kind, Loc)); return None; } diff --git a/test/MC/PowerPC/ppc64-reloc-directive-pcrel.s b/test/MC/PowerPC/ppc64-reloc-directive-pcrel.s new file mode 100644 index 00000000000..c17445f0a50 --- /dev/null +++ b/test/MC/PowerPC/ppc64-reloc-directive-pcrel.s @@ -0,0 +1,401 @@ +# RUN: llvm-mc -triple=powerpc64le -filetype=obj %s | \ +# RUN: llvm-objdump -dr --mcpu=pwr10 - | FileCheck %s +# RUN: llvm-mc -triple=powerpc64 -filetype=obj %s | \ +# RUN: llvm-objdump -dr --mcpu=pwr10 - | FileCheck %s + + +## +# This section of tests contains the MCBinaryExpr as the first parameter of the +# .reloc relocation. +## + .text + .abiversion 2 + .globl Minimal + .p2align 4 + .type Minimal,@function +Minimal: +.LMinimal$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel1: + .reloc .Lpcrel1-8,R_PPC64_PCREL_OPT,.-(.Lpcrel1-8) + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK-LABEL: Minimal +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x8 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + .globl SingleInsnBetween + .p2align 4 + .type SingleInsnBetween,@function +SingleInsnBetween: +.LSingleInsnBetween$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel2: + addi 3, 3, 42 + .reloc .Lpcrel2-8,R_PPC64_PCREL_OPT,.-(.Lpcrel2-8) + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK_LABEL: SingleInsnBetween +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0xc +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + + .globl MultiInsnBetween # -- Begin function + .p2align 4 + .type MultiInsnBetween,@function +MultiInsnBetween: +.LMultiInsnBetween$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel3: + addi 3, 3, 42 + addi 3, 3, 42 + addi 3, 3, 42 + addi 3, 3, 42 + addi 3, 3, 42 + .reloc .Lpcrel3-8,R_PPC64_PCREL_OPT,.-(.Lpcrel3-8) + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK_LABEL: MultiInsnBetween +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x1c +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + .globl PrefixInsnBetween + .p2align 6 + .type PrefixInsnBetween,@function + .space 48 # Add a space to force an alignment of a paddi. +PrefixInsnBetween: +.LPrefixInsnBetween$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel4: + addi 3, 3, 42 + paddi 3, 3, 42, 0 + addi 3, 3, 42 + paddi 3, 3, 42, 0 + addi 3, 3, 42 + .reloc .Lpcrel4-8,R_PPC64_PCREL_OPT,.-(.Lpcrel4-8) + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK_LABEL: PrefixInsnBetween +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x28 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: nop +# CHECK-NEXT: paddi 3, 3, 42, 0 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: paddi 3, 3, 42, 0 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + + .globl SpaceBetween # -- Begin function + .p2align 4 + .type SpaceBetween,@function +SpaceBetween: +.LSpaceBetween$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel5: + addi 3, 3, 42 + paddi 3, 3, 42, 0 + addi 3, 3, 42 + .space 40, 0 + paddi 3, 3, 42, 0 + addi 3, 3, 42 + .reloc .Lpcrel5-8,R_PPC64_PCREL_OPT,.-(.Lpcrel5-8) + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK_LABEL: SpaceBetween +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x50 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: nop +# CHECK-NEXT: paddi 3, 3, 42, 0 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK: paddi 3, 3, 42, 0 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + + .globl Plus + .p2align 4 + .type Plus,@function +Plus: +.LPlus$local: +.Lpcrel6: + addi 3, 3, 42 + addi 3, 3, 42 + pld 3, vec@got@pcrel(0), 1 + .reloc .Lpcrel6+8,R_PPC64_PCREL_OPT,.-(.Lpcrel6+8) + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK-LABEL: Plus +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x8 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + +## +# This section of tests contains the variable MCSymbol as part of the +# MCSymbolRefExpr for the first parameter of the .reloc relocation. +## + .globl VarLabelMinimal # -- Begin function + .p2align 4 + .type VarLabelMinimal,@function +VarLabelMinimal: +.LVarLabelMinimal$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel101=.-8 + .reloc .Lpcrel101,R_PPC64_PCREL_OPT,.-.Lpcrel101 + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK-LABEL: VarLabelMinimal +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x8 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + + .globl VarLabelSingleInsnBetween + .p2align 4 + .type VarLabelSingleInsnBetween,@function +VarLabelSingleInsnBetween: +.LVarLabelSingleInsnBetween$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel102=.-8 + addi 3, 3, 42 + .reloc .Lpcrel102,R_PPC64_PCREL_OPT,.-.Lpcrel102 + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK_LABEL: VarLabelSingleInsnBetween +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0xc +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + .globl VarLabelMultiInsnBetween # -- Begin function + .p2align 4 + .type VarLabelMultiInsnBetween,@function +VarLabelMultiInsnBetween: +.LVarLabelMultiInsnBetween$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel103=.-8 + addi 3, 3, 42 + addi 3, 3, 42 + addi 3, 3, 42 + addi 3, 3, 42 + addi 3, 3, 42 + .reloc .Lpcrel103,R_PPC64_PCREL_OPT,.-.Lpcrel103 + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK_LABEL: VarLabelMultiInsnBetween +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x1c +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + + .globl VarLabelPrefixInsnBetween # -- Begin function + .p2align 4 + .type VarLabelPrefixInsnBetween,@function +VarLabelPrefixInsnBetween: +.LVarLabelPrefixInsnBetween$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel104=.-8 + addi 3, 3, 42 + paddi 3, 3, 42, 0 + addi 3, 3, 42 + paddi 3, 3, 42, 0 + addi 3, 3, 42 + .reloc .Lpcrel104,R_PPC64_PCREL_OPT,.-.Lpcrel104 + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK_LABEL: VarLabelPrefixInsnBetween +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x24 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: paddi 3, 3, 42, 0 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: paddi 3, 3, 42, 0 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + + .globl VarLabelSpaceBetween # -- Begin function + .p2align 4 + .type VarLabelSpaceBetween,@function +VarLabelSpaceBetween: +.LVarLabelSpaceBetween$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel105=.-8 + addi 3, 3, 42 + paddi 3, 3, 42, 0 + addi 3, 3, 42 + .space 40, 0 + paddi 3, 3, 42, 0 + addi 3, 3, 42 + .reloc .Lpcrel105,R_PPC64_PCREL_OPT,.-.Lpcrel105 + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK_LABEL: VarLabelSpaceBetween +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x4c +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: paddi 3, 3, 42, 0 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK: paddi 3, 3, 42, 0 +# CHECK-NEXT: addi 3, 3, 42 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + + .globl VarLabelPlus + .p2align 4 + .type VarLabelPlus,@function +VarLabelPlus: +.LVarLabelPlus$local: +.Lpcrel106: + addi 3, 3, 42 + addi 3, 3, 42 + pld 3, vec@got@pcrel(0), 1 + .reloc .Lpcrel106+8,R_PPC64_PCREL_OPT,.-(.Lpcrel106+8) + lwa 3, 4(3) + blr + .long 0 + .quad 0 +# CHECK-LABEL: VarLabelPlus +# CHECK: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x8 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + +# Check the situation where the PLD requires an alignment nop. + .globl AlignPLD + .p2align 6 + .type AlignPLD,@function + .space 60 # Force the pld to require an alignment nop. +AlignPLD: +.LAlignPLD$local: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel201: + .reloc .Lpcrel201-8,R_PPC64_PCREL_OPT,.-(.Lpcrel201-8) + lwa 3, 4(3) + blr +# CHECK-LABEL: AlignPLD +# CHECK: nop +# CHECK-NEXT: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x8 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + +# The label and the pld are on the same line and so the nop is inserted before +# the label and the relocation should work. + .globl AlignPLDSameLine + .p2align 6 + .type AlignPLDSameLine,@function + .space 60 # Force the pld to require an alignment nop. +AlignPLDSameLine: +.LAlignPLDSameLine$local: +.Lpcrel202: pld 3, vec@got@pcrel(0), 1 + .reloc .Lpcrel202,R_PPC64_PCREL_OPT,.-.Lpcrel202 + lwa 3, 4(3) + blr +# CHECK-LABEL: AlignPLDSameLine +# CHECK: nop +# CHECK-NEXT: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x8 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + .globl AlignPLDLabelBefore + .p2align 6 + .type AlignPLDLabelBefore,@function + .space 60 # Force the pld to require an alignment nop. +AlignPLDLabelBefore: +.LAlignPLDLabelBefore$local: +.Label: + pld 3, vec@got@pcrel(0), 1 +.Lpcrel203: + .reloc .Lpcrel203-8,R_PPC64_PCREL_OPT,.-(.Lpcrel203-8) + lwa 3, 4(3) + blr +# CHECK-LABEL: AlignPLDLabelBefore +# CHECK: nop +# CHECK-NEXT: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x8 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr + + .globl AlignPLDLabelSameLine + .p2align 6 + .type AlignPLDLabelSameLine,@function + .space 60 # Force the pld to require an alignment nop. +AlignPLDLabelSameLine: +.Label2: pld 3, vec@got@pcrel(0), 1 +.Lpcrel204: + .reloc .Lpcrel204-8,R_PPC64_PCREL_OPT,.-(.Lpcrel204-8) + lwa 3, 4(3) + blr +# CHECK-LABEL: AlignPLDLabelSameLine +# CHECK: nop +# CHECK-NEXT: pld 3, 0(0), 1 +# CHECK-NEXT: R_PPC64_GOT_PCREL34 vec +# CHECK-NEXT: R_PPC64_PCREL_OPT *ABS*+0x8 +# CHECK-NEXT: lwa 3, 4(3) +# CHECK-NEXT: blr