[llvm] 406dc54 - [dfsan] Refactor defining TLS variables

[Jianzhou Zhao via llvm-commits]

Author: Jianzhou Zhao
Date: 2021-02-18T18:04:21Z
New Revision: 406dc549034adc4da5e6f45ef3d9aef98c177331

URL: https://github.com/llvm/llvm-project/commit/406dc549034adc4da5e6f45ef3d9aef98c177331
DIFF: https://github.com/llvm/llvm-project/commit/406dc549034adc4da5e6f45ef3d9aef98c177331.diff

LOG: [dfsan] Refactor defining TLS variables

This is a part of https://reviews.llvm.org/D95835.

Reviewed-by: morehouse

Differential Revision: https://reviews.llvm.org/D96941

Added: 
    

Modified: 
    llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index 10e510baee74..de3831870627 100644
--- a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -1098,19 +1098,23 @@ bool DataFlowSanitizer::runImpl(Module &M) {
 
   bool Changed = false;
 
-  Type *ArgTLSTy = ArrayType::get(Type::getInt64Ty(*Ctx), kArgTLSSize / 8);
-  ArgTLS = Mod->getOrInsertGlobal("__dfsan_arg_tls", ArgTLSTy);
-  if (GlobalVariable *G = dyn_cast<GlobalVariable>(ArgTLS)) {
-    Changed |= G->getThreadLocalMode() != GlobalVariable::InitialExecTLSModel;
-    G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
-  }
-  Type *RetvalTLSTy =
-      ArrayType::get(Type::getInt64Ty(*Ctx), kRetvalTLSSize / 8);
-  RetvalTLS = Mod->getOrInsertGlobal("__dfsan_retval_tls", RetvalTLSTy);
-  if (GlobalVariable *G = dyn_cast<GlobalVariable>(RetvalTLS)) {
-    Changed |= G->getThreadLocalMode() != GlobalVariable::InitialExecTLSModel;
-    G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
-  }
+  auto getOrInsertGlobal = [this, &Changed](StringRef Name,
+                                            Type *Ty) -> Constant * {
+    Constant *C = Mod->getOrInsertGlobal(Name, Ty);
+    if (GlobalVariable *G = dyn_cast<GlobalVariable>(C)) {
+      Changed |= G->getThreadLocalMode() != GlobalVariable::InitialExecTLSModel;
+      G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
+    }
+    return C;
+  };
+
+  // These globals must be kept in sync with the ones in dfsan.cpp.
+  ArgTLS = getOrInsertGlobal(
+      "__dfsan_arg_tls",
+      ArrayType::get(Type::getInt64Ty(*Ctx), kArgTLSSize / 8));
+  RetvalTLS = getOrInsertGlobal(
+      "__dfsan_retval_tls",
+      ArrayType::get(Type::getInt64Ty(*Ctx), kRetvalTLSSize / 8));
 
   ExternalShadowMask =
       Mod->getOrInsertGlobal(kDFSanExternShadowPtrMask, IntptrTy);