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-rw-r--r--llvm/include/llvm/ExecutionEngine/JITLink/aarch32.h162
1 files changed, 90 insertions, 72 deletions
diff --git a/llvm/include/llvm/ExecutionEngine/JITLink/aarch32.h b/llvm/include/llvm/ExecutionEngine/JITLink/aarch32.h
index f346cfb2a931..eda6feb441e6 100644
--- a/llvm/include/llvm/ExecutionEngine/JITLink/aarch32.h
+++ b/llvm/include/llvm/ExecutionEngine/JITLink/aarch32.h
@@ -41,7 +41,13 @@ enum EdgeKind_aarch32 : Edge::Kind {
/// Absolute 32-bit value relocation
Data_Pointer32,
- LastDataRelocation = Data_Pointer32,
+ /// Relative 31-bit value relocation that preserves the most-significant bit
+ Data_PRel31,
+
+ /// Create GOT entry and store offset
+ Data_RequestGOTAndTransformToDelta32,
+
+ LastDataRelocation = Data_RequestGOTAndTransformToDelta32,
///
/// Relocations of class Arm (covers fixed-width 4-byte instruction subset)
@@ -98,7 +104,11 @@ enum EdgeKind_aarch32 : Edge::Kind {
Thumb_MovtPrel,
LastThumbRelocation = Thumb_MovtPrel,
- LastRelocation = LastThumbRelocation,
+
+ /// No-op relocation
+ None,
+
+ LastRelocation = None,
};
/// Flags enum for AArch32-specific symbol properties
@@ -123,32 +133,29 @@ const char *getEdgeKindName(Edge::Kind K);
///
/// Stubs are often called "veneers" in the official docs and online.
///
-enum StubsFlavor {
- Unsupported = 0,
- Thumbv7,
+enum class StubsFlavor {
+ Undefined = 0,
+ pre_v7,
+ v7,
};
/// JITLink sub-arch configuration for Arm CPU models
struct ArmConfig {
bool J1J2BranchEncoding = false;
- StubsFlavor Stubs = Unsupported;
+ StubsFlavor Stubs = StubsFlavor::Undefined;
+ // In the long term, we might want a linker switch like --target1-rel
+ bool Target1Rel = false;
};
/// Obtain the sub-arch configuration for a given Arm CPU model.
inline ArmConfig getArmConfigForCPUArch(ARMBuildAttrs::CPUArch CPUArch) {
ArmConfig ArmCfg;
- switch (CPUArch) {
- case ARMBuildAttrs::v7:
- case ARMBuildAttrs::v8_A:
+ if (CPUArch == ARMBuildAttrs::v7 || CPUArch >= ARMBuildAttrs::v7E_M) {
ArmCfg.J1J2BranchEncoding = true;
- ArmCfg.Stubs = Thumbv7;
- break;
- default:
- DEBUG_WITH_TYPE("jitlink", {
- dbgs() << " Warning: ARM config not defined for CPU architecture "
- << getCPUArchName(CPUArch);
- });
- break;
+ ArmCfg.Stubs = StubsFlavor::v7;
+ } else {
+ ArmCfg.J1J2BranchEncoding = false;
+ ArmCfg.Stubs = StubsFlavor::pre_v7;
}
return ArmCfg;
}
@@ -288,7 +295,8 @@ inline Expected<int64_t> readAddend(LinkGraph &G, Block &B,
if (Kind <= LastThumbRelocation)
return readAddendThumb(G, B, Offset, Kind, ArmCfg);
- llvm_unreachable("Relocation must be of class Data, Arm or Thumb");
+ assert(Kind == None && "Not associated with a relocation class");
+ return 0;
}
/// Helper function to apply the fixup for Data-class relocations.
@@ -315,76 +323,86 @@ inline Error applyFixup(LinkGraph &G, Block &B, const Edge &E,
if (Kind <= LastThumbRelocation)
return applyFixupThumb(G, B, E, ArmCfg);
- llvm_unreachable("Relocation must be of class Data, Arm or Thumb");
+ assert(Kind == None && "Not associated with a relocation class");
+ return Error::success();
}
-/// Stubs builder for a specific StubsFlavor
-///
-/// Right now we only have one default stub kind, but we want to extend this
-/// and allow creation of specific kinds in the future (e.g. branch range
-/// extension or interworking).
-///
-/// Let's keep it simple for the moment and not wire this through a GOT.
-///
-template <StubsFlavor Flavor>
-class StubsManager : public TableManager<StubsManager<Flavor>> {
+/// Populate a Global Offset Table from edges that request it.
+class GOTBuilder : public TableManager<GOTBuilder> {
public:
- StubsManager() = default;
+ static StringRef getSectionName() { return "$__GOT"; }
- /// Name of the object file section that will contain all our stubs.
- static StringRef getSectionName();
+ bool visitEdge(LinkGraph &G, Block *B, Edge &E);
+ Symbol &createEntry(LinkGraph &G, Symbol &Target);
- /// Implements link-graph traversal via visitExistingEdges().
- bool visitEdge(LinkGraph &G, Block *B, Edge &E) {
- if (E.getTarget().isDefined())
- return false;
-
- switch (E.getKind()) {
- case Thumb_Call:
- case Thumb_Jump24: {
- DEBUG_WITH_TYPE("jitlink", {
- dbgs() << " Fixing " << G.getEdgeKindName(E.getKind()) << " edge at "
- << B->getFixupAddress(E) << " (" << B->getAddress() << " + "
- << formatv("{0:x}", E.getOffset()) << ")\n";
- });
- E.setTarget(this->getEntryForTarget(G, E.getTarget()));
- return true;
- }
- }
- return false;
+private:
+ Section *GOTSection = nullptr;
+};
+
+/// Stubs builder emits non-position-independent Arm stubs for pre-v7 CPUs.
+/// These architectures have no MovT/MovW instructions and don't support Thumb2.
+/// BL is the only Thumb instruction that can generate stubs and they can always
+/// be transformed into BLX.
+class StubsManager_prev7 {
+public:
+ StubsManager_prev7() = default;
+
+ /// Name of the object file section that will contain all our stubs.
+ static StringRef getSectionName() {
+ return "__llvm_jitlink_aarch32_STUBS_prev7";
}
- /// Create a branch range extension stub for the class's flavor.
- Symbol &createEntry(LinkGraph &G, Symbol &Target);
+ /// Implements link-graph traversal via visitExistingEdges()
+ bool visitEdge(LinkGraph &G, Block *B, Edge &E);
private:
- /// Create a new node in the link-graph for the given stub template.
- template <size_t Size>
- Block &addStub(LinkGraph &G, const uint8_t (&Code)[Size],
- uint64_t Alignment) {
- ArrayRef<char> Template(reinterpret_cast<const char *>(Code), Size);
- return G.createContentBlock(getStubsSection(G), Template,
- orc::ExecutorAddr(), Alignment, 0);
+ // Each stub uses a single block that can have 2 entryponts, one for Arm and
+ // one for Thumb
+ struct StubMapEntry {
+ Block *B = nullptr;
+ Symbol *ArmEntry = nullptr;
+ Symbol *ThumbEntry = nullptr;
+ };
+
+ std::pair<StubMapEntry *, bool> getStubMapSlot(StringRef Name) {
+ auto &&[Stubs, NewStub] = StubMap.try_emplace(Name);
+ return std::make_pair(&Stubs->second, NewStub);
}
- /// Get or create the object file section that will contain all our stubs.
- Section &getStubsSection(LinkGraph &G) {
- if (!StubsSection)
- StubsSection = &G.createSection(getSectionName(),
- orc::MemProt::Read | orc::MemProt::Exec);
- return *StubsSection;
- }
+ Symbol *getOrCreateSlotEntrypoint(LinkGraph &G, StubMapEntry &Slot,
+ bool Thumb);
+ DenseMap<StringRef, StubMapEntry> StubMap;
Section *StubsSection = nullptr;
};
-/// Create a branch range extension stub with Thumb encoding for v7 CPUs.
-template <>
-Symbol &StubsManager<Thumbv7>::createEntry(LinkGraph &G, Symbol &Target);
+/// Stubs builder for v7 emits non-position-independent Arm and Thumb stubs.
+class StubsManager_v7 {
+public:
+ StubsManager_v7() = default;
+
+ /// Name of the object file section that will contain all our stubs.
+ static StringRef getSectionName() {
+ return "__llvm_jitlink_aarch32_STUBS_v7";
+ }
-template <> inline StringRef StubsManager<Thumbv7>::getSectionName() {
- return "__llvm_jitlink_aarch32_STUBS_Thumbv7";
-}
+ /// Implements link-graph traversal via visitExistingEdges().
+ bool visitEdge(LinkGraph &G, Block *B, Edge &E);
+
+private:
+ // Two slots per external: Arm and Thumb
+ using StubMapEntry = std::tuple<Symbol *, Symbol *>;
+
+ Symbol *&getStubSymbolSlot(StringRef Name, bool Thumb) {
+ StubMapEntry &Stubs = StubMap.try_emplace(Name).first->second;
+ if (Thumb)
+ return std::get<1>(Stubs);
+ return std::get<0>(Stubs);
+ }
+
+ DenseMap<StringRef, StubMapEntry> StubMap;
+ Section *StubsSection = nullptr;
+};
} // namespace aarch32
} // namespace jitlink
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