Add EH support to the MCJIT.
This gets exception handling working on ELF and Macho (x86-64 at least).
Other than the EH frame registration, this patch also implements support
for GOT relocations which are used to locate the personality function on
MachO.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181167 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp
index b3467a9..01a3fd9 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp
@@ -21,6 +21,69 @@
namespace llvm {
+static unsigned char *processFDE(unsigned char *P, intptr_t DeltaForText, intptr_t DeltaForEH) {
+ uint32_t Length = *((uint32_t*)P);
+ P += 4;
+ unsigned char *Ret = P + Length;
+ uint32_t Offset = *((uint32_t*)P);
+ if (Offset == 0) // is a CIE
+ return Ret;
+
+ P += 4;
+ intptr_t FDELocation = *((intptr_t*)P);
+ intptr_t NewLocation = FDELocation - DeltaForText;
+ *((intptr_t*)P) = NewLocation;
+ P += sizeof(intptr_t);
+
+ // Skip the FDE address range
+ P += sizeof(intptr_t);
+
+ uint8_t Augmentationsize = *P;
+ P += 1;
+ if (Augmentationsize != 0) {
+ intptr_t LSDA = *((intptr_t*)P);
+ intptr_t NewLSDA = LSDA - DeltaForEH;
+ *((intptr_t*)P) = NewLSDA;
+ }
+
+ return Ret;
+}
+
+static intptr_t computeDelta(SectionEntry *A, SectionEntry *B) {
+ intptr_t ObjDistance = A->ObjAddress - B->ObjAddress;
+ intptr_t MemDistance = A->LoadAddress - B->LoadAddress;
+ return ObjDistance - MemDistance;
+}
+
+StringRef RuntimeDyldMachO::getEHFrameSection() {
+ SectionEntry *Text = NULL;
+ SectionEntry *EHFrame = NULL;
+ SectionEntry *ExceptTab = NULL;
+ for (int i = 0, e = Sections.size(); i != e; ++i) {
+ if (Sections[i].Name == "__eh_frame")
+ EHFrame = &Sections[i];
+ else if (Sections[i].Name == "__text")
+ Text = &Sections[i];
+ else if (Sections[i].Name == "__gcc_except_tab")
+ ExceptTab = &Sections[i];
+ }
+ if (Text == NULL || EHFrame == NULL)
+ return StringRef();
+
+ intptr_t DeltaForText = computeDelta(Text, EHFrame);
+ intptr_t DeltaForEH = 0;
+ if (ExceptTab)
+ DeltaForEH = computeDelta(ExceptTab, EHFrame);
+
+ unsigned char *P = EHFrame->Address;
+ unsigned char *End = P + EHFrame->Size;
+ do {
+ P = processFDE(P, DeltaForText, DeltaForEH);
+ } while(P != End);
+
+ return StringRef((char*)EHFrame->Address, EHFrame->Size);
+}
+
void RuntimeDyldMachO::resolveRelocation(const RelocationEntry &RE,
uint64_t Value) {
const SectionEntry &Section = Sections[RE.SectionID];
@@ -267,7 +330,30 @@
Value.Addend = Addend - Addr;
}
- if (Arch == Triple::arm && (RelType & 0xf) == macho::RIT_ARM_Branch24Bit) {
+ if (Arch == Triple::x86_64 && RelType == macho::RIT_X86_64_GOT) {
+ assert(IsPCRel);
+ assert(Size == 2);
+ StubMap::const_iterator i = Stubs.find(Value);
+ uint8_t *Addr;
+ if (i != Stubs.end()) {
+ Addr = Section.Address + i->second;
+ } else {
+ Stubs[Value] = Section.StubOffset;
+ uint8_t *GOTEntry = Section.Address + Section.StubOffset;
+ RelocationEntry RE(SectionID, Section.StubOffset,
+ macho::RIT_X86_64_Unsigned, Value.Addend - 4, false,
+ 3);
+ if (Value.SymbolName)
+ addRelocationForSymbol(RE, Value.SymbolName);
+ else
+ addRelocationForSection(RE, Value.SectionID);
+ Section.StubOffset += 8;
+ Addr = GOTEntry;
+ }
+ resolveRelocation(Section, Offset, (uint64_t)Addr,
+ macho::RIT_X86_64_Unsigned, 4, true, 2);
+ } else if (Arch == Triple::arm &&
+ (RelType & 0xf) == macho::RIT_ARM_Branch24Bit) {
// This is an ARM branch relocation, need to use a stub function.
// Look up for existing stub.