| /* |
| * Copyright 2010, The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #define LOG_TAG "bcc" |
| #include <cutils/log.h> |
| |
| #include "CodeMemoryManager.h" |
| #include "ContextManager.h" |
| |
| #include "llvm/Support/ErrorHandling.h" |
| |
| #include <sys/mman.h> |
| |
| #include <assert.h> |
| #include <stddef.h> |
| |
| #include <map> |
| #include <string> |
| #include <utility> |
| |
| |
| namespace bcc { |
| |
| |
| const unsigned int MaxCodeSize = BCC_CONTEXT_CODE_SIZE; |
| const unsigned int MaxGOTSize = 1 * 1024; |
| const unsigned int MaxGlobalVarSize = BCC_CONTEXT_DATA_SIZE; |
| |
| |
| CodeMemoryManager::CodeMemoryManager() |
| : mpCodeMem(NULL), mpGVMem(NULL), mpGOTBase(NULL) { |
| |
| reset(); |
| std::string ErrMsg; |
| |
| mpCodeMem = allocateContext(); |
| |
| if (!mpCodeMem) { |
| LOGE("Unable to allocate mpCodeMem\n"); |
| llvm::report_fatal_error("Failed to allocate memory for emitting " |
| "codes\n" + ErrMsg); |
| } |
| |
| // Set global variable pool |
| mpGVMem = mpCodeMem + MaxCodeSize; |
| |
| return; |
| } |
| |
| |
| CodeMemoryManager::~CodeMemoryManager() { |
| mpCodeMem = 0; |
| mpGVMem = 0; |
| } |
| |
| |
| uint8_t *CodeMemoryManager::allocateSGMemory(uintptr_t Size, |
| unsigned Alignment) { |
| |
| intptr_t FreeMemSize = getFreeCodeMemSize(); |
| if ((FreeMemSize < 0) || (static_cast<uintptr_t>(FreeMemSize) < Size)) |
| // The code size excesses our limit |
| return NULL; |
| |
| if (Alignment == 0) |
| Alignment = 1; |
| |
| uint8_t *result = getCodeMemBase() + mCurSGMemIdx - Size; |
| result = (uint8_t*) (((intptr_t) result) & ~(intptr_t) (Alignment - 1)); |
| |
| mCurSGMemIdx = result - getCodeMemBase(); |
| |
| return result; |
| } |
| |
| |
| // setMemoryWritable - When code generation is in progress, the code pages |
| // may need permissions changed. |
| void CodeMemoryManager::setMemoryWritable() { |
| mprotect(mpCodeMem, MaxCodeSize, PROT_READ | PROT_WRITE | PROT_EXEC); |
| } |
| |
| |
| // When code generation is done and we're ready to start execution, the |
| // code pages may need permissions changed. |
| void CodeMemoryManager::setMemoryExecutable() { |
| mprotect(mpCodeMem, MaxCodeSize, PROT_READ | PROT_EXEC); |
| } |
| |
| |
| // Setting this flag to true makes the memory manager garbage values over |
| // freed memory. This is useful for testing and debugging, and is to be |
| // turned on by default in debug mode. |
| void CodeMemoryManager::setPoisonMemory(bool poison) { |
| // no effect |
| } |
| |
| |
| // Global Offset Table Management |
| |
| // If the current table requires a Global Offset Table, this method is |
| // invoked to allocate it. This method is required to set HasGOT to true. |
| void CodeMemoryManager::AllocateGOT() { |
| assert(mpGOTBase != NULL && "Cannot allocate the GOT multiple times"); |
| mpGOTBase = allocateSGMemory(MaxGOTSize); |
| HasGOT = true; |
| } |
| |
| |
| // Main Allocation Functions |
| |
| // When we start JITing a function, the JIT calls this method to allocate a |
| // block of free RWX memory, which returns a pointer to it. If the JIT wants |
| // to request a block of memory of at least a certain size, it passes that |
| // value as ActualSize, and this method returns a block with at least that |
| // much space. If the JIT doesn't know ahead of time how much space it will |
| // need to emit the function, it passes 0 for the ActualSize. In either |
| // case, this method is required to pass back the size of the allocated |
| // block through ActualSize. The JIT will be careful to not write more than |
| // the returned ActualSize bytes of memory. |
| uint8_t *CodeMemoryManager::startFunctionBody(const llvm::Function *F, |
| uintptr_t &ActualSize) { |
| intptr_t FreeMemSize = getFreeCodeMemSize(); |
| if ((FreeMemSize < 0) || |
| (static_cast<uintptr_t>(FreeMemSize) < ActualSize)) |
| // The code size excesses our limit |
| return NULL; |
| |
| ActualSize = getFreeCodeMemSize(); |
| return (getCodeMemBase() + mCurFuncMemIdx); |
| } |
| |
| // This method is called when the JIT is done codegen'ing the specified |
| // function. At this point we know the size of the JIT compiled function. |
| // This passes in FunctionStart (which was returned by the startFunctionBody |
| // method) and FunctionEnd which is a pointer to the actual end of the |
| // function. This method should mark the space allocated and remember where |
| // it is in case the client wants to deallocate it. |
| void CodeMemoryManager::endFunctionBody(const llvm::Function *F, |
| uint8_t *FunctionStart, |
| uint8_t *FunctionEnd) { |
| assert(FunctionEnd > FunctionStart); |
| assert(FunctionStart == (getCodeMemBase() + mCurFuncMemIdx) && |
| "Mismatched function start/end!"); |
| |
| // Advance the pointer |
| intptr_t FunctionCodeSize = FunctionEnd - FunctionStart; |
| assert(FunctionCodeSize <= getFreeCodeMemSize() && |
| "Code size excess the limitation!"); |
| mCurFuncMemIdx += FunctionCodeSize; |
| |
| // Record there's a function in our memory start from @FunctionStart |
| assert(mFunctionMap.find(F) == mFunctionMap.end() && |
| "Function already emitted!"); |
| mFunctionMap.insert( |
| std::make_pair<const llvm::Function*, std::pair<void*, void*> >( |
| F, std::make_pair(FunctionStart, FunctionEnd))); |
| |
| return; |
| } |
| |
| // Allocate a (function code) memory block of the given size. This method |
| // cannot be called between calls to startFunctionBody and endFunctionBody. |
| uint8_t *CodeMemoryManager::allocateSpace(intptr_t Size, unsigned Alignment) { |
| if (getFreeCodeMemSize() < Size) { |
| // The code size excesses our limit |
| return NULL; |
| } |
| |
| if (Alignment == 0) |
| Alignment = 1; |
| |
| uint8_t *result = getCodeMemBase() + mCurFuncMemIdx; |
| result = (uint8_t*) (((intptr_t) result + Alignment - 1) & |
| ~(intptr_t) (Alignment - 1)); |
| |
| mCurFuncMemIdx = (result + Size) - getCodeMemBase(); |
| |
| return result; |
| } |
| |
| // Allocate memory for a global variable. |
| uint8_t *CodeMemoryManager::allocateGlobal(uintptr_t Size, unsigned Alignment) { |
| if (getFreeGVMemSize() < Size) { |
| // The code size excesses our limit |
| LOGE("No Global Memory"); |
| return NULL; |
| } |
| |
| if (Alignment == 0) |
| Alignment = 1; |
| |
| uint8_t *result = getGVMemBase() + mCurGVMemIdx; |
| result = (uint8_t*) (((intptr_t) result + Alignment - 1) & |
| ~(intptr_t) (Alignment - 1)); |
| |
| mCurGVMemIdx = (result + Size) - getGVMemBase(); |
| |
| return result; |
| } |
| |
| // Free the specified function body. The argument must be the return value |
| // from a call to startFunctionBody() that hasn't been deallocated yet. This |
| // is never called when the JIT is currently emitting a function. |
| void CodeMemoryManager::deallocateFunctionBody(void *Body) { |
| // linear search |
| uint8_t *FunctionStart = NULL, *FunctionEnd = NULL; |
| for (FunctionMapTy::iterator I = mFunctionMap.begin(), |
| E = mFunctionMap.end(); I != E; I++) { |
| if (I->second.first == Body) { |
| FunctionStart = reinterpret_cast<uint8_t*>(I->second.first); |
| FunctionEnd = reinterpret_cast<uint8_t*>(I->second.second); |
| break; |
| } |
| } |
| |
| assert((FunctionStart == NULL) && "Memory is never allocated!"); |
| |
| // free the memory |
| intptr_t SizeNeedMove = (getCodeMemBase() + mCurFuncMemIdx) - FunctionEnd; |
| |
| assert(SizeNeedMove >= 0 && |
| "Internal error: CodeMemoryManager::mCurFuncMemIdx may not" |
| " be correctly calculated!"); |
| |
| if (SizeNeedMove > 0) { |
| // there's data behind deallocating function |
| memmove(FunctionStart, FunctionEnd, SizeNeedMove); |
| } |
| |
| mCurFuncMemIdx -= (FunctionEnd - FunctionStart); |
| } |
| |
| // Below are the methods we create |
| void CodeMemoryManager::reset() { |
| mpGOTBase = NULL; |
| HasGOT = false; |
| |
| mCurFuncMemIdx = 0; |
| mCurSGMemIdx = MaxCodeSize - 1; |
| mCurGVMemIdx = 0; |
| |
| mFunctionMap.clear(); |
| } |
| |
| } // namespace bcc |