[XRay][clang] Make -fxray-modes= additive

Summary:
This allows us to do the following:

  clang -fxray-modes=none ... -fxray-modes=xray-basic

It's important to be able to do this in cases where we'd like to
specialise the configuration for the invocation of the compiler, in
various scripting environments.

This is related to llvm.org/PR37066, a follow-up to D45474.

Reviewers: eizan, kpw, pelikan

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D45610

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@329989 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Driver/XRayArgs.cpp

@@ -146,21 +146,16 @@ XRayArgs::XRayArgs(const ToolChain &TC, const ArgList &Args) {
       llvm::copy(XRaySupportedModes, std::back_inserter(Modes));
     else
       for (const auto &Arg : SpecifiedModes) {
-        if (Arg == "none") {
-          Modes.clear();
-          break;
-        }
-        if (Arg == "all") {
-          Modes.clear();
-          llvm::copy(XRaySupportedModes, std::back_inserter(Modes));
-          break;
-        }
-
         // Parse CSV values for -fxray-modes=...
         llvm::SmallVector<StringRef, 2> ModeParts;
         llvm::SplitString(Arg, ModeParts, ",");
         for (const auto &M : ModeParts)
-          Modes.push_back(M);
+          if (M == "none")
+            Modes.clear();
+          else if (M == "all")
+            llvm::copy(XRaySupportedModes, std::back_inserter(Modes));
+          else
+            Modes.push_back(M);
       }
 
     // Then we want to sort and unique the modes we've collected.
@@ -205,4 +200,10 @@ void XRayArgs::addArgs(const ToolChain &TC, const ArgList &Args,
     ExtraDepOpt += Dep;
     CmdArgs.push_back(Args.MakeArgString(ExtraDepOpt));
   }
+
+  for (const auto &Mode : Modes) {
+    SmallString<64> ModeOpt("-fxray-modes=");
+    ModeOpt += Mode;
+    CmdArgs.push_back(Args.MakeArgString(ModeOpt));
+  }
 }

test/Driver/XRay/xray-mode-flags.cpp

@@ -14,6 +14,18 @@
 // RUN:     2>&1 | FileCheck --check-prefixes FDR,BASIC %s
 // RUN: %clang -v -o /dev/null -fxray-instrument -fxray-modes=none -### %s \
 // RUN:     2>&1 | FileCheck --check-prefixes NONE %s
+//
+// We also should support overriding the modes in an additive manner.
+//
+// RUN: %clang -v -o /dev/null -fxray-instrument -fxray-modes=none,xray-fdr \
+// RUN:     -### %s \
+// RUN:     2>&1 | FileCheck --check-prefixes FDR %s
+// RUN: %clang -v -o /dev/null -fxray-instrument -fxray-modes=xray-fdr,none \
+// RUN:     -### %s \
+// RUN:     2>&1 | FileCheck --check-prefixes NONE %s
+// RUN: %clang -v -o /dev/null -fxray-instrument -fxray-modes=none,all \
+// RUN:     -### %s \
+// RUN:     2>&1 | FileCheck --check-prefixes FDR,BASIC %s
 
 // BASIC: libclang_rt.xray-basic
 // FDR: libclang_rt.xray-fdr