[clang][xray] Add xray attributes to functions without decls too

[ianlevesque]

Summary

This allows instrumenting things like global initializers

[dberris]

LGTM

clang/lib/CodeGen/CodeGenFunction.cpp

#undef SANITIZER
   // are not aware of how to move the extra UBSan instructions across the split
   // coroutine boundaries.
   if (D && SanOpts.has(SanitizerKind::Null))
     if (const auto *FD = dyn_cast<FunctionDecl>(D))
       if (FD->getBody() &&
           FD->getBody()->getStmtClass() == Stmt::CoroutineBodyStmtClass)
         SanOpts.Mask &= ~SanitizerKind::Null;
 
-  if (D) {
-    // Apply xray attributes to the function (as a string, for now)
-    if (const auto *XRayAttr = D->getAttr<XRayInstrumentAttr>()) {
-      if (CGM.getCodeGenOpts().XRayInstrumentationBundle.has(
-              XRayInstrKind::FunctionEntry) ||
-          CGM.getCodeGenOpts().XRayInstrumentationBundle.has(
-              XRayInstrKind::FunctionExit)) {
-        if (XRayAttr->alwaysXRayInstrument() && ShouldXRayInstrumentFunction())
-          Fn->addFnAttr("function-instrument", "xray-always");
-        if (XRayAttr->neverXRayInstrument())
-          Fn->addFnAttr("function-instrument", "xray-never");
-        if (const auto *LogArgs = D->getAttr<XRayLogArgsAttr>())
-          if (ShouldXRayInstrumentFunction())
-            Fn->addFnAttr("xray-log-args",
-                          llvm::utostr(LogArgs->getArgumentCount()));
-      }
-    } else {
-      if (ShouldXRayInstrumentFunction() && !CGM.imbueXRayAttrs(Fn, Loc))
-        Fn->addFnAttr(
-            "xray-instruction-threshold",
-            llvm::itostr(CGM.getCodeGenOpts().XRayInstructionThreshold));
-    }
+  if (const auto *XRayAttr = D ? D->getAttr<XRayInstrumentAttr>() : nullptr) {
 
-    if (ShouldXRayInstrumentFunction()) {
-      if (CGM.getCodeGenOpts().XRayIgnoreLoops)
-        Fn->addFnAttr("xray-ignore-loops");
 
-      if (!CGM.getCodeGenOpts().XRayInstrumentationBundle.has(
-              XRayInstrKind::FunctionExit))
-        Fn->addFnAttr("xray-skip-exit");
 
-      if (!CGM.getCodeGenOpts().XRayInstrumentationBundle.has(
-              XRayInstrKind::FunctionEntry))
-        Fn->addFnAttr("xray-skip-entry");
-    }
 
-    unsigned Count, Offset;
-    if (const auto *Attr = D->getAttr<PatchableFunctionEntryAttr>()) {
-      Count = Attr->getCount();
-      Offset = Attr->getOffset();
-    } else {
-      Count = CGM.getCodeGenOpts().PatchableFunctionEntryCount;
-      Offset = CGM.getCodeGenOpts().PatchableFunctionEntryOffset;
-    }
-    if (Count && Offset <= Count) {
-      Fn->addFnAttr("patchable-function-entry", std::to_string(Count - Offset));
-      if (Offset)
-        Fn->addFnAttr("patchable-function-prefix", std::to_string(Offset));
-    }
-  }
+  if (const auto *Attr =
+          D ? D->getAttr<PatchableFunctionEntryAttr>() : nullptr) {
 
   // Add no-jump-tables value.
   Fn->addFnAttr("no-jump-tables",
                 llvm::toStringRef(CGM.getCodeGenOpts().NoUseJumpTables));
 
   // Add no-inline-line-tables value.
   if (CGM.getCodeGenOpts().NoInlineLineTables)
     Fn->addFnAttr("no-inline-line-tables");

clang/test/CodeGen/xray-global-init.cpp

+// RUN: %clang_cc1 -triple=x86_64-linux-gnu -emit-llvm -fxray-instrument -fxray-instruction-threshold=1 %s -o - \
+// RUN:   | FileCheck %s
+
+struct A {
+  A();
+  ~A();
+};
+
+A a;
+
+// Check that the xray-instruction-threshold was applied
+// CHECK: define internal void @_GLOBAL__sub_I_xray_global_init.cpp() [[NUX:#[0-9]+]] section ".text.startup" {
+// CHECK: attributes [[NUX]] = { noinline nounwind {{.*}}"xray-instruction-threshold"="1"{{.*}} }