vendor/llvm-project/llvmorg-11-init-20887-g2e10b7a39b9vendor/llvm-project/master

1 files changed, 134 insertions, 38 deletions

diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
index 5881a0a86ef7..bb1f1cc7f49a 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
@@ -9,6 +9,7 @@
 #include "RISCVAsmBackend.h"
 #include "RISCVMCExpr.h"
 #include "llvm/ADT/APInt.h"
+#include "llvm/MC/MCAsmLayout.h"
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCDirectives.h"
@@ -22,14 +23,75 @@
 
 using namespace llvm;
 
+Optional<MCFixupKind> RISCVAsmBackend::getFixupKind(StringRef Name) const {
+  if (STI.getTargetTriple().isOSBinFormatELF()) {
+    unsigned Type;
+    Type = llvm::StringSwitch<unsigned>(Name)
+#define ELF_RELOC(X, Y) .Case(#X, Y)
+#include "llvm/BinaryFormat/ELFRelocs/RISCV.def"
+#undef ELF_RELOC
+               .Default(-1u);
+    if (Type != -1u)
+      return static_cast<MCFixupKind>(FirstLiteralRelocationKind + Type);
+  }
+  return None;
+}
+
+const MCFixupKindInfo &
+RISCVAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
+  const static MCFixupKindInfo Infos[] = {
+      // This table *must* be in the order that the fixup_* kinds are defined in
+      // RISCVFixupKinds.h.
+      //
+      // name                      offset bits  flags
+      {"fixup_riscv_hi20", 12, 20, 0},
+      {"fixup_riscv_lo12_i", 20, 12, 0},
+      {"fixup_riscv_lo12_s", 0, 32, 0},
+      {"fixup_riscv_pcrel_hi20", 12, 20,
+       MCFixupKindInfo::FKF_IsPCRel | MCFixupKindInfo::FKF_IsTarget},
+      {"fixup_riscv_pcrel_lo12_i", 20, 12,
+       MCFixupKindInfo::FKF_IsPCRel | MCFixupKindInfo::FKF_IsTarget},
+      {"fixup_riscv_pcrel_lo12_s", 0, 32,
+       MCFixupKindInfo::FKF_IsPCRel | MCFixupKindInfo::FKF_IsTarget},
+      {"fixup_riscv_got_hi20", 12, 20, MCFixupKindInfo::FKF_IsPCRel},
+      {"fixup_riscv_tprel_hi20", 12, 20, 0},
+      {"fixup_riscv_tprel_lo12_i", 20, 12, 0},
+      {"fixup_riscv_tprel_lo12_s", 0, 32, 0},
+      {"fixup_riscv_tprel_add", 0, 0, 0},
+      {"fixup_riscv_tls_got_hi20", 12, 20, MCFixupKindInfo::FKF_IsPCRel},
+      {"fixup_riscv_tls_gd_hi20", 12, 20, MCFixupKindInfo::FKF_IsPCRel},
+      {"fixup_riscv_jal", 12, 20, MCFixupKindInfo::FKF_IsPCRel},
+      {"fixup_riscv_branch", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
+      {"fixup_riscv_rvc_jump", 2, 11, MCFixupKindInfo::FKF_IsPCRel},
+      {"fixup_riscv_rvc_branch", 0, 16, MCFixupKindInfo::FKF_IsPCRel},
+      {"fixup_riscv_call", 0, 64, MCFixupKindInfo::FKF_IsPCRel},
+      {"fixup_riscv_call_plt", 0, 64, MCFixupKindInfo::FKF_IsPCRel},
+      {"fixup_riscv_relax", 0, 0, 0},
+      {"fixup_riscv_align", 0, 0, 0}};
+  static_assert((array_lengthof(Infos)) == RISCV::NumTargetFixupKinds,
+                "Not all fixup kinds added to Infos array");
+
+  // Fixup kinds from .reloc directive are like R_RISCV_NONE. They
+  // do not require any extra processing.
+  if (Kind >= FirstLiteralRelocationKind)
+    return MCAsmBackend::getFixupKindInfo(FK_NONE);
+
+  if (Kind < FirstTargetFixupKind)
+    return MCAsmBackend::getFixupKindInfo(Kind);
+
+  assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
+         "Invalid kind!");
+  return Infos[Kind - FirstTargetFixupKind];
+}
+
 // If linker relaxation is enabled, or the relax option had previously been
 // enabled, always emit relocations even if the fixup can be resolved. This is
 // necessary for correctness as offsets may change during relaxation.
 bool RISCVAsmBackend::shouldForceRelocation(const MCAssembler &Asm,
                                             const MCFixup &Fixup,
                                             const MCValue &Target) {
-  bool ShouldForce = false;
-
+  if (Fixup.getKind() >= FirstLiteralRelocationKind)
+    return true;
   switch (Fixup.getTargetKind()) {
   default:
     break;
@@ -44,40 +106,9 @@ bool RISCVAsmBackend::shouldForceRelocation(const MCAssembler &Asm,
   case RISCV::fixup_riscv_tls_got_hi20:
   case RISCV::fixup_riscv_tls_gd_hi20:
     return true;
-  case RISCV::fixup_riscv_pcrel_lo12_i:
-  case RISCV::fixup_riscv_pcrel_lo12_s:
-    // For pcrel_lo12, force a relocation if the target of the corresponding
-    // pcrel_hi20 is not in the same fragment.
-    const MCFixup *T = cast<RISCVMCExpr>(Fixup.getValue())->getPCRelHiFixup();
-    if (!T) {
-      Asm.getContext().reportError(Fixup.getLoc(),
-                                   "could not find corresponding %pcrel_hi");
-      return false;
-    }
-
-    switch (T->getTargetKind()) {
-    default:
-      llvm_unreachable("Unexpected fixup kind for pcrel_lo12");
-      break;
-    case RISCV::fixup_riscv_got_hi20:
-    case RISCV::fixup_riscv_tls_got_hi20:
-    case RISCV::fixup_riscv_tls_gd_hi20:
-      ShouldForce = true;
-      break;
-    case RISCV::fixup_riscv_pcrel_hi20: {
-      MCFragment *TFragment = T->getValue()->findAssociatedFragment();
-      MCFragment *FixupFragment = Fixup.getValue()->findAssociatedFragment();
-      assert(FixupFragment && "We should have a fragment for this fixup");
-      ShouldForce =
-          !TFragment || TFragment->getParent() != FixupFragment->getParent();
-      break;
-    }
-    }
-    break;
   }
 
-  return ShouldForce || STI.getFeatureBits()[RISCV::FeatureRelax] ||
-         ForceRelocs;
+  return STI.getFeatureBits()[RISCV::FeatureRelax] || ForceRelocs;
 }
 
 bool RISCVAsmBackend::fixupNeedsRelaxationAdvanced(const MCFixup &Fixup,
@@ -108,10 +139,10 @@ bool RISCVAsmBackend::fixupNeedsRelaxationAdvanced(const MCFixup &Fixup,
   }
 }
 
-void RISCVAsmBackend::relaxInstruction(const MCInst &Inst,
-                                       const MCSubtargetInfo &STI,
-                                       MCInst &Res) const {
+void RISCVAsmBackend::relaxInstruction(MCInst &Inst,
+                                       const MCSubtargetInfo &STI) const {
   // TODO: replace this with call to auto generated uncompressinstr() function.
+  MCInst Res;
   switch (Inst.getOpcode()) {
   default:
     llvm_unreachable("Opcode not expected!");
@@ -142,6 +173,7 @@ void RISCVAsmBackend::relaxInstruction(const MCInst &Inst,
     Res.addOperand(Inst.getOperand(0));
     break;
   }
+  Inst = std::move(Res);
 }
 
 // Given a compressed control flow instruction this function returns
@@ -284,13 +316,77 @@ static uint64_t adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
   }
 }
 
+bool RISCVAsmBackend::evaluateTargetFixup(
+    const MCAssembler &Asm, const MCAsmLayout &Layout, const MCFixup &Fixup,
+    const MCFragment *DF, const MCValue &Target, uint64_t &Value,
+    bool &WasForced) {
+  const MCFixup *AUIPCFixup;
+  const MCFragment *AUIPCDF;
+  MCValue AUIPCTarget;
+  switch (Fixup.getTargetKind()) {
+  default:
+    llvm_unreachable("Unexpected fixup kind!");
+  case RISCV::fixup_riscv_pcrel_hi20:
+    AUIPCFixup = &Fixup;
+    AUIPCDF = DF;
+    AUIPCTarget = Target;
+    break;
+  case RISCV::fixup_riscv_pcrel_lo12_i:
+  case RISCV::fixup_riscv_pcrel_lo12_s: {
+    AUIPCFixup = cast<RISCVMCExpr>(Fixup.getValue())->getPCRelHiFixup(&AUIPCDF);
+    if (!AUIPCFixup) {
+      Asm.getContext().reportError(Fixup.getLoc(),
+                                   "could not find corresponding %pcrel_hi");
+      return true;
+    }
+
+    // MCAssembler::evaluateFixup will emit an error for this case when it sees
+    // the %pcrel_hi, so don't duplicate it when also seeing the %pcrel_lo.
+    const MCExpr *AUIPCExpr = AUIPCFixup->getValue();
+    if (!AUIPCExpr->evaluateAsRelocatable(AUIPCTarget, &Layout, AUIPCFixup))
+      return true;
+    break;
+  }
+  }
+
+  if (!AUIPCTarget.getSymA() || AUIPCTarget.getSymB())
+    return false;
+
+  const MCSymbolRefExpr *A = AUIPCTarget.getSymA();
+  const MCSymbol &SA = A->getSymbol();
+  if (A->getKind() != MCSymbolRefExpr::VK_None || SA.isUndefined())
+    return false;
+
+  auto *Writer = Asm.getWriterPtr();
+  if (!Writer)
+    return false;
+
+  bool IsResolved = Writer->isSymbolRefDifferenceFullyResolvedImpl(
+      Asm, SA, *AUIPCDF, false, true);
+  if (!IsResolved)
+    return false;
+
+  Value = Layout.getSymbolOffset(SA) + AUIPCTarget.getConstant();
+  Value -= Layout.getFragmentOffset(AUIPCDF) + AUIPCFixup->getOffset();
+
+  if (shouldForceRelocation(Asm, *AUIPCFixup, AUIPCTarget)) {
+    WasForced = true;
+    return false;
+  }
+
+  return true;
+}
+
 void RISCVAsmBackend::applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
                                  const MCValue &Target,
                                  MutableArrayRef<char> Data, uint64_t Value,
                                  bool IsResolved,
                                  const MCSubtargetInfo *STI) const {
+  MCFixupKind Kind = Fixup.getKind();
+  if (Kind >= FirstLiteralRelocationKind)
+    return;
   MCContext &Ctx = Asm.getContext();
-  MCFixupKindInfo Info = getFixupKindInfo(Fixup.getKind());
+  MCFixupKindInfo Info = getFixupKindInfo(Kind);
   if (!Value)
     return; // Doesn't change encoding.
   // Apply any target-specific value adjustments.