[PR] Instrumentation: Initial support for static executables

Summary:
This commit introduces static binaries instrumentation
support.  Note that current implementation does not support profile
output on the instrumented binary finalization. So it requires to use
-instrumentation-sleep-time=N (N>0) option usage.  Note: There is
unhandled case with static PIE executable which might have dynamic
header.

Vasily Leonenko,
Advanced Software Technology Lab, Huawei

(cherry picked from FBD30092471)

bolt/src/MCPlusBuilder.h

@@ -1771,6 +1771,11 @@ class MCPlusBuilder {
     return std::vector<MCInst>();
   }
 
+  virtual std::vector<MCInst> createDummyReturnFunction(MCContext *Ctx) const {
+    llvm_unreachable("not implemented");
+    return std::vector<MCInst>();
+  }
+
   /// This method takes an indirect call instruction and splits it up into an
   /// equivalent set of instructions that use direct calls for target
   /// symbols/addresses that are contained in the Targets vector.  This is done

bolt/src/Passes/Instrumentation.cpp

@@ -651,6 +651,12 @@ void Instrumentation::createAuxiliaryFunctions(BinaryContext &BC) {
       createSimpleFunction(
           "__bolt_fini_trampoline",
           BC.MIB->createSymbolTrampoline(FiniSym, BC.Ctx.get()));
+    } else {
+      // Create dummy return function for trampoline to avoid issues
+      // with unknown symbol in runtime library. E.g. for static PIE
+      // executable
+      createSimpleFunction("__bolt_fini_trampoline",
+                           BC.MIB->createDummyReturnFunction(BC.Ctx.get()));
     }
   }
 }

bolt/src/RewriteInstance.cpp

@@ -5075,6 +5075,7 @@ void RewriteInstance::readELFDynamic(ELFObjectFile<ELFT> *File) {
 
   if (!DynamicPhdr) {
     outs() << "BOLT-INFO: static input executable detected\n";
+    // TODO: static PIE executable might have dynamic header
     BC->IsStaticExecutable = true;
     return;
   }

bolt/src/RuntimeLibs/InstrumentationRuntimeLibrary.cpp

@@ -59,7 +59,7 @@ void InstrumentationRuntimeLibrary::adjustCommandLineOptions(
               "the input binary\n";
     exit(1);
   }
-  if (!BC.FiniFunctionAddress) {
+  if (!BC.FiniFunctionAddress && !BC.IsStaticExecutable) {
     errs() << "BOLT-ERROR: input binary lacks DT_FINI entry in the dynamic "
               "section but instrumentation currently relies on patching "
               "DT_FINI to write the profile\n";
@@ -86,6 +86,13 @@ void InstrumentationRuntimeLibrary::emitBinary(BinaryContext &BC,
                                  "__BOLT", "__counters", MachO::S_REGULAR,
                                  SectionKind::getData()));
 
+  if (BC.IsStaticExecutable && !opts::InstrumentationSleepTime) {
+    errs() << "BOLT-ERROR: instrumentation of static binary currently does not "
+              "support profile output on binary finalization, so it "
+              "requires -instrumentation-sleep-time=N (N>0) usage\n";
+    exit(1);
+  }
+
   Section->setAlignment(llvm::Align(BC.RegularPageSize));
   Streamer.SwitchSection(Section);
 

bolt/src/Target/X86/X86MCPlusBuilder.cpp

@@ -3316,6 +3316,12 @@ class X86MCPlusBuilder : public MCPlusBuilder {
     return Insts;
   }
 
+  std::vector<MCInst> createDummyReturnFunction(MCContext *Ctx) const override {
+    std::vector<MCInst> Insts(1);
+    createReturn(Insts[0]);
+    return Insts;
+  }
+
   BlocksVectorTy indirectCallPromotion(
     const MCInst &CallInst,
     const std::vector<std::pair<MCSymbol *, uint64_t>> &Targets,