[RuntimeDyld] Skip relocations for external symbols with 64-bit address ~0ULL.

Requested by Eugene Rozenfeld of the LLILC team, this feature allows JIT
clients to skip relocations for selected external symbols by returning ~0ULL
from their symbol resolver. If this value is returned for a given symbol,
RuntimeDyld will skip all relocations for that symbol. The client will be
responsible for applying the skipped relocations manually before the code
is executed.

llvm-svn: 241383

2 files changed, 13 insertions, 7 deletions

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index 092c696d53e..6851625b9e9 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -815,12 +815,16 @@ void RuntimeDyldImpl::resolveExternalSymbols() {
         report_fatal_error("Program used external function '" + Name +
                            "' which could not be resolved!");
 
-      DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
-                   << format("0x%lx", Addr) << "\n");
-      // This list may have been updated when we called getSymbolAddress, so
-      // don't change this code to get the list earlier.
-      RelocationList &Relocs = i->second;
-      resolveRelocationList(Relocs, Addr);
+      // If Resolver returned UINT64_MAX, the client wants to handle this symbol
+      // manually and we shouldn't resolve its relocations.
+      if (Addr != UINT64_MAX) {
+        DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
+                     << format("0x%lx", Addr) << "\n");
+        // This list may have been updated when we called getSymbolAddress, so
+        // don't change this code to get the list earlier.
+        RelocationList &Relocs = i->second;
+        resolveRelocationList(Relocs, Addr);
+      }
     }
 
     ExternalSymbolRelocations.erase(i);
diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp
index 957571b092d..ae199b72022 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp
@@ -727,7 +727,9 @@ bool RuntimeDyldCheckerImpl::checkAllRulesInBuffer(StringRef RulePrefix,
 }
 
 bool RuntimeDyldCheckerImpl::isSymbolValid(StringRef Symbol) const {
-  return getRTDyld().getSymbolLocalAddress(Symbol) != nullptr;
+  if (getRTDyld().getSymbolLocalAddress(Symbol))
+    return true;
+  return !!getRTDyld().Resolver.findSymbol(Symbol);
 }
 
 uint64_t RuntimeDyldCheckerImpl::getSymbolLocalAddr(StringRef Symbol) const {