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Correct PIC function stub codegen.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59006 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2008-11-10 23:14:47 +00:00
parent 0ef3b61c98
commit 588920b9a5
2 changed files with 52 additions and 7 deletions
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39
lib/Target/ARM/ARMJITInfo.cpp
View File

@ -19,6 +19,7 @@
#include "llvm/Function.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/Config/alloca.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Streams.h"
#include "llvm/System/Memory.h"
#include <cstdlib>
@ -133,7 +134,9 @@ void *ARMJITInfo::emitGlobalValueIndirectSym(const GlobalValue *GV, void *Ptr,
MachineCodeEmitter &MCE) {
MCE.startGVStub(GV, 4, 4);
MCE.emitWordLE((intptr_t)Ptr);
return MCE.finishGVStub(GV);
void *PtrAddr = MCE.finishGVStub(GV);
addIndirectSymAddr(Ptr, (intptr_t)PtrAddr);
return PtrAddr;
}
void *ARMJITInfo::emitFunctionStub(const Function* F, void *Fn,
@ -142,12 +145,34 @@ void *ARMJITInfo::emitFunctionStub(const Function* F, void *Fn,
// call. The code is the same except for one bit of the last instruction.
if (Fn != (void*)(intptr_t)ARMCompilationCallback) {
// Branch to the corresponding function addr.
// The stub is 8-byte size and 4-aligned.
MCE.startGVStub(F, 8, 4);
intptr_t Addr = (intptr_t)MCE.getCurrentPCValue();
MCE.emitWordLE(0xe51ff004); // ldr pc, [pc, #-4]
MCE.emitWordLE((intptr_t)Fn); // addr of function
sys::Memory::InvalidateInstructionCache((void*)Addr, 8);
if (IsPIC) {
// The stub is 8-byte size and 4-aligned.
intptr_t LazyPtr = getIndirectSymAddr(Fn);
if (!LazyPtr) {
// In PIC mode, the function stub is loading a lazy-ptr.
LazyPtr= (intptr_t)emitGlobalValueIndirectSym((GlobalValue*)F, Fn, MCE);
if (F)
DOUT << "JIT: Indirect symbol emitted at [" << LazyPtr << "] for GV '"
<< F->getName() << "'\n";
else
DOUT << "JIT: Stub emitted at [" << LazyPtr
<< "] for external function at '" << Fn << "'\n";
}
MCE.startGVStub(F, 16, 4);
intptr_t Addr = (intptr_t)MCE.getCurrentPCValue();
MCE.emitWordLE(0xe59fc004); // ldr pc, [pc, #+4]
MCE.emitWordLE(0xe08fc00c); // L_func$scv: add ip, pc, ip
MCE.emitWordLE(0xe59cf000); // ldr pc, [ip]
MCE.emitWordLE(LazyPtr - (Addr+4+8)); // func - (L_func$scv+8)
sys::Memory::InvalidateInstructionCache((void*)Addr, 16);
} else {
// The stub is 8-byte size and 4-aligned.
MCE.startGVStub(F, 8, 4);
intptr_t Addr = (intptr_t)MCE.getCurrentPCValue();
MCE.emitWordLE(0xe51ff004); // ldr pc, [pc, #-4]
MCE.emitWordLE((intptr_t)Fn); // addr of function
sys::Memory::InvalidateInstructionCache((void*)Addr, 8);
}
} else {
// The compilation callback will overwrite the first two words of this
// stub with indirect branch instructions targeting the compiled code.

20
lib/Target/ARM/ARMJITInfo.h
View File

@ -37,6 +37,10 @@ namespace llvm {
// PCLabelMap - A map from PC labels to addresses.
DenseMap<unsigned, intptr_t> PCLabelMap;
// Sym2IndirectSymMap - A map from symbol (GlobalValue and ExternalSymbol)
// addresses to their indirect symbol addresses.
DenseMap<void*, intptr_t> Sym2IndirectSymMap;
// IsPIC - True if the relocation model is PIC. This is used to determine
// how to codegen function stubs.
bool IsPIC;
@ -147,6 +151,22 @@ namespace llvm {
PCLabelMap.insert(std::make_pair(Id, Addr));
}
/// getIndirectSymAddr - Retrieve the address of the indirect symbol of the
/// specified symbol located at address. Returns 0 if the indirect symbol
/// has not been emitted.
intptr_t getIndirectSymAddr(void *Addr) const {
DenseMap<void*,intptr_t>::const_iterator I= Sym2IndirectSymMap.find(Addr);
if (I != Sym2IndirectSymMap.end())
return I->second;
return 0;
}
/// addIndirectSymAddr - Add a mapping from address of an emitted symbol to
/// its indirect symbol address.
void addIndirectSymAddr(void *SymAddr, intptr_t IndSymAddr) {
Sym2IndirectSymMap.insert(std::make_pair(SymAddr, IndSymAddr));
}
private:
/// resolveRelocDestAddr - Resolve the resulting address of the relocation
/// if it's not already solved. Constantpool entries must be resolved by