fix compilation errors with clang CreateFromArgs() change (iovisor#2528)

Upstream change https://reviews.llvm.org/D66797 (in llvm 10)
changed signature of CreateFromArgs(). Compiled with latest upstream,
we will have compilation error like:
    /home/yhs/work/bcc/src/cc/frontends/clang/loader.cc:343:57:
    error: ‘cargs’ was not declared in this scope; did you mean ‘ccargs’?
      343 |   if (!CompilerInvocation::CreateFromArgs( invocation0, cargs.  diags))
          |                                                         ^~~~~
          |                                                         ccargs

Adjust bcc codes to use the new func signature.

Signed-off-by: Yonghong Song <[email protected]>

src/cc/frontends/clang/loader.cc

@@ -102,6 +102,19 @@ std::pair<bool, string> get_kernel_path_info(const string kdir)
  return std::make_pair(false, "build");
 }
 
+static int CreateFromArgs(clang::CompilerInvocation &invocation,
+ const llvm::opt::ArgStringList &ccargs,
+ clang::DiagnosticsEngine &diags)
+{
+#if LLVM_MAJOR_VERSION >= 10
+ return clang::CompilerInvocation::CreateFromArgs(invocation, ccargs, diags);
+#else
+ return clang::CompilerInvocation::CreateFromArgs(
+ invocation, const_cast<const char **>(ccargs.data()),
+ const_cast<const char **>(ccargs.data()) + ccargs.size(), diags);
+#endif
+}
+
 }
 
 int ClangLoader::parse(unique_ptr<llvm::Module> *mod, TableStorage &ts,
@@ -339,9 +352,7 @@ int ClangLoader::do_compile(unique_ptr<llvm::Module> *mod, TableStorage &ts,
  // pre-compilation pass for generating tracepoint structures
  CompilerInstance compiler0;
  CompilerInvocation &invocation0 = compiler0.getInvocation();
- if (!CompilerInvocation::CreateFromArgs(
- invocation0, const_cast<const char **>(ccargs.data()),
- const_cast<const char **>(ccargs.data()) + ccargs.size(), diags))
+ if (!CreateFromArgs(invocation0, ccargs, diags))
  return -1;
 
  invocation0.getPreprocessorOpts().RetainRemappedFileBuffers = true;
@@ -370,9 +381,7 @@ int ClangLoader::do_compile(unique_ptr<llvm::Module> *mod, TableStorage &ts,
  // first pass
  CompilerInstance compiler1;
  CompilerInvocation &invocation1 = compiler1.getInvocation();
- if (!CompilerInvocation::CreateFromArgs(
- invocation1, const_cast<const char **>(ccargs.data()),
- const_cast<const char **>(ccargs.data()) + ccargs.size(), diags))
+ if (!CreateFromArgs( invocation1, ccargs, diags))
  return -1;
 
  // This option instructs clang whether or not to free the file buffers that we
@@ -403,10 +412,9 @@ int ClangLoader::do_compile(unique_ptr<llvm::Module> *mod, TableStorage &ts,
  // second pass, clear input and take rewrite buffer
  CompilerInstance compiler2;
  CompilerInvocation &invocation2 = compiler2.getInvocation();
- if (!CompilerInvocation::CreateFromArgs(
- invocation2, const_cast<const char **>(ccargs.data()),
- const_cast<const char **>(ccargs.data()) + ccargs.size(), diags))
+ if (!CreateFromArgs(invocation2, ccargs, diags))
  return -1;
+
  invocation2.getPreprocessorOpts().RetainRemappedFileBuffers = true;
  for (const auto &f : remapped_headers_)
  invocation2.getPreprocessorOpts().addRemappedFile(f.first, &*f.second);