Guard dynamic library loading.
I did my best at implementing this for Win32, but I don't have a way to test it.
Can someone with access to a Win32 machine test/fix this?
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74188 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/DynamicLibrary.cpp b/lib/System/DynamicLibrary.cpp
index 3bf172c..ef5c9e6 100644
--- a/lib/System/DynamicLibrary.cpp
+++ b/lib/System/DynamicLibrary.cpp
@@ -12,20 +12,22 @@
//===----------------------------------------------------------------------===//
#include "llvm/System/DynamicLibrary.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/System/RWMutex.h"
#include "llvm/Config/config.h"
#include <cstdio>
#include <cstring>
#include <map>
// Collection of symbol name/value pairs to be searched prior to any libraries.
-std::map<std::string, void *> &g_symbols() {
- static std::map<std::string, void *> symbols;
- return symbols;
-}
+static std::map<std::string, void*> symbols;
+static llvm::sys::SmartRWMutex<true> SymbolsLock;
+
void llvm::sys::DynamicLibrary::AddSymbol(const char* symbolName,
void *symbolValue) {
- g_symbols()[symbolName] = symbolValue;
+ llvm::sys::SmartScopedWriter<true> Writer(&SymbolsLock);
+ symbols[symbolName] = symbolValue;
}
// It is not possible to use ltdl.c on VC++ builds as the terms of its LGPL
@@ -57,6 +59,7 @@
DynamicLibrary::DynamicLibrary() {}
DynamicLibrary::~DynamicLibrary() {
+ SmartScopedWriter<true> Writer(&SymbolsLock);
while(!OpenedHandles.empty()) {
void *H = OpenedHandles.back(); OpenedHandles.pop_back();
dlclose(H);
@@ -65,6 +68,7 @@
bool DynamicLibrary::LoadLibraryPermanently(const char *Filename,
std::string *ErrMsg) {
+ SmartScopedWriter<true> Writer(&SymbolsLock);
void *H = dlopen(Filename, RTLD_LAZY|RTLD_GLOBAL);
if (H == 0) {
if (ErrMsg)
@@ -77,20 +81,28 @@
void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
// check_ltdl_initialization();
-
+
// First check symbols added via AddSymbol().
- std::map<std::string, void *>::iterator I = g_symbols().find(symbolName);
- if (I != g_symbols().end())
+ SymbolsLock.reader_acquire();
+ std::map<std::string, void *>::iterator I = symbols.find(symbolName);
+ std::map<std::string, void *>::iterator E = symbols.end();
+ SymbolsLock.reader_release();
+
+ if (I != E)
return I->second;
+ SymbolsLock.writer_acquire();
// Now search the libraries.
for (std::vector<void *>::iterator I = OpenedHandles.begin(),
E = OpenedHandles.end(); I != E; ++I) {
//lt_ptr ptr = lt_dlsym(*I, symbolName);
void *ptr = dlsym(*I, symbolName);
- if (ptr)
+ if (ptr) {
+ SymbolsLock.writer_release();
return ptr;
+ }
}
+ SymbolsLock.writer_release();
#define EXPLICIT_SYMBOL(SYM) \
extern void *SYM; if (!strcmp(symbolName, #SYM)) return &SYM