TSAN module_ctor symbol name can change with -funique-internal-linkage-names

[tmsriram]

Summary

tsan.module_ctor symbol name can change with -funique-internal-linkage-names which is captured in this patch.

With option, -funique-internal-linkage-names, the name of tsan.module_ctor is actually tsan.module_ctor.__uniq.[0-9]+

The option -funique-internal-linkage-names adds a sufix (.uniq.[0-9]+) to every internal linkage function to keep the name unique in the final binary. tsan.module_ctor is one such function which has internal linkage. This function name is checked in ThreadSanitizer.cpp to make sure we don't insturment it with tsan_func_{entry,exit}. This patch makes sure we even check the name when -funique-internal-linakge-names is used.

[tmsriram]

D96109 moved the adding of suffixes to clang front end and this will not be an issue any more with llvm created functions.

llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp

 STATISTIC(NumInstrumentedVtableWrites, "Number of vtable ptr writes");
 STATISTIC(NumInstrumentedVtableReads, "Number of vtable ptr reads");
 STATISTIC(NumOmittedReadsFromConstantGlobals,
           "Number of reads from constant globals");
 STATISTIC(NumOmittedReadsFromVtable, "Number of vtable reads");
 STATISTIC(NumOmittedNonCaptured, "Number of accesses ignored due to capturing");
 
 const char kTsanModuleCtorName[] = "tsan.module_ctor";
+// This is the prefix when -funique-internal-linkage-names is used.
+const char kTsanModuleCtorNameUniq[] = "tsan.module_ctor.__uniq";
 const char kTsanInitName[] = "__tsan_init";
 
 namespace {
 
 /// ThreadSanitizer: instrument the code in module to find races.
 ///
 /// Instantiating ThreadSanitizer inserts the tsan runtime library API function
 /// declarations into the module if they don't exist already. Instantiating
while (IRBuilder<> *AtExit = EE.Next()) {
     AtExit->CreateCall(TsanIgnoreEnd);
   }
 }
 
 bool ThreadSanitizer::sanitizeFunction(Function &F,
                                        const TargetLibraryInfo &TLI) {
   // This is required to prevent instrumenting call to __tsan_init from within
   // the module constructor.
-  if (F.getName() == kTsanModuleCtorName)
+  if (F.getName() == kTsanModuleCtorName
+      || F.getName().startswith(kTsanModuleCtorNameUniq))
     return false;
   // Naked functions can not have prologue/epilogue
   // (__tsan_func_entry/__tsan_func_exit) generated, so don't instrument them at
   // all.
   if (F.hasFnAttribute(Attribute::Naked))
     return false;
   initialize(*F.getParent());
   SmallVector<InstructionInfo, 8> AllLoadsAndStores;

llvm/test/Instrumentation/ThreadSanitizer/tsan_basic.ll

 ; RUN: opt < %s -tsan -S -enable-new-pm=0 | FileCheck %s
+; RUN: opt < %s -tsan -unique-internal-linkage-names -S -enable-new-pm=0 | FileCheck %s
 ; RUN: opt < %s -passes='function(tsan),module(tsan-module)' -S | FileCheck %s
+; RUN: opt < %s -passes='function(tsan),module(tsan-module),unique-internal-linkage-names' -S | FileCheck %s
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-unknown-linux-gnu"
 
 define i32 @read_4_bytes(i32* %a) sanitize_thread {
 entry:
   %tmp1 = load i32, i32* %a, align 4
   ret i32 %tmp1

 define i32 @NakedTest(i32* %a) naked sanitize_thread {
   call void @foo()
   %tmp1 = load i32, i32* %a, align 4
   ret i32 %tmp1
 }
 
 declare void @foo() nounwind
 
-; CHECK: define internal void @tsan.module_ctor()
+; CHECK: define internal void @tsan.module_ctor
 ; CHECK: call void @__tsan_init()