0003-clang-add-conda-specific-env-var-CONDA_BUILD_SYSROOT.patch

From f957da489fc5d49f04051430965496d4708cf9f4 Mon Sep 17 00:00:00 2001
From: Nehal J Wani <nehaljw.kkd1@gmail.com>
Date: Sat, 25 Aug 2018 09:20:04 -0500
Subject: [PATCH 3/9] clang: add conda specific env var CONDA_BUILD_SYSROOT

And also improve logic for finding the macos sysroot for conda

Co-authored-by: Chris Burr <christopher.burr@cern.ch>
Co-authored-by: Vincenzo Eduardo Padulano <v.e.padulano@gmail.com>
Co-authored-by: Isuru Fernando <isuruf@gmail.com>
---
 clang/lib/Driver/Driver.cpp            |  5 ++
 clang/lib/Driver/ToolChains/Darwin.cpp | 76 +++++++++++++++++++++++++-
 clang/lib/Lex/InitHeaderSearch.cpp     |  6 +-
 3 files changed, 84 insertions(+), 3 deletions(-)

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 8e44d5afa40e..9c66a52a9887 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1371,6 +1371,11 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
       CompilerPath = Split.second;
     }
   }
+  if (std::optional<std::string> CondaBuildSysrootValue =
+          llvm::sys::Process::GetEnv("CONDA_BUILD_SYSROOT")) {
+    SysRoot = *CondaBuildSysrootValue;
+  }
+  // Override CONDA_BUILD_SYSROOT and consume sysroot option
   if (const Arg *A = Args.getLastArg(options::OPT__sysroot_EQ))
     SysRoot = A->getValue();
   if (const Arg *A = Args.getLastArg(options::OPT__dyld_prefix_EQ))
diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index 17d57b2f7eed..99747a4fb1aa 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -29,6 +29,18 @@
 #include "llvm/TargetParser/Triple.h"
 #include <cstdlib> // ::getenv
 
+// Extra includes for conda patch
+#include <cstdio>
+#include <memory>
+#include <optional>
+#include <string>
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FileUtilities.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Program.h"
+
 using namespace clang::driver;
 using namespace clang::driver::tools;
 using namespace clang::driver::toolchains;
@@ -2217,15 +2229,75 @@ void Darwin::AddDeploymentTarget(DerivedArgList &Args) const {
     if (!getVFS().exists(A->getValue()))
       getDriver().Diag(clang::diag::warn_missing_sysroot) << A->getValue();
   } else {
+    std::string foundSDKPath = "/";
+    std::string prefixToTry = "/";
+
     if (char *env = ::getenv("SDKROOT")) {
       // We only use this value as the default if it is an absolute path,
       // exists, and it is not the root path.
       if (llvm::sys::path::is_absolute(env) && getVFS().exists(env) &&
           StringRef(env) != "/") {
-        Args.append(Args.MakeSeparateArg(
-            nullptr, Opts.getOption(options::OPT_isysroot), env));
+        foundSDKPath = std::string(env);
+      }
+    }
+
+    if (foundSDKPath == "/") {
+      if (char *env = ::getenv("CONDA_BUILD_SYSROOT")) {
+        // We only use this value as the default if it is an absolute path,
+        // exists, and it is not the root path.
+        if (llvm::sys::path::is_absolute(env) && getVFS().exists(env) &&
+            StringRef(env) != "/") {
+          foundSDKPath = std::string(env);
+        }
       }
     }
+
+    // If the SDK is not found by now and it's not inside /, our only choice
+    // is to fail or ask Apple CLI utilities for help
+    if (foundSDKPath == "/" && !getVFS().exists("/usr/include/sys/types.h")) {
+
+      auto pathFromExecutable = [](llvm::ArrayRef<llvm::StringRef> Argv)
+          -> std::optional<std::string> {
+        // Inspired by clang-tools-extra/clangd/CompileCommands.cpp
+        auto Exe = llvm::sys::findProgramByName(Argv[0]);
+        if (!Exe) {
+          return std::nullopt;
+        }
+        llvm::SmallString<64> OutFile;
+        llvm::sys::fs::createTemporaryFile("darwin-adddeploymenttarget", "",
+                                           OutFile);
+        llvm::FileRemover OutRemover(OutFile);
+        std::optional<llvm::StringRef> Redirects[3] = {
+            /*stdin=*/{""}, /*stdout=*/{OutFile.str()}, /*stderr=*/{""}};
+        int Ret = llvm::sys::ExecuteAndWait(*Exe, Argv,
+                                            /*Env=*/std::nullopt, Redirects,
+                                            /*SecondsToWait=*/10);
+        if (Ret != 0) {
+          return std::nullopt;
+        }
+
+        auto Buf = llvm::MemoryBuffer::getFile(OutFile);
+        if (!Buf) {
+          return std::nullopt;
+        }
+        llvm::StringRef Path = Buf->get()->getBuffer().trim();
+        if (Path.empty()) {
+          return std::nullopt;
+        }
+        return Path.str();
+      };
+
+      auto XcrunPath = pathFromExecutable({"xcrun", "--show-sdk-path"});
+      if (foundSDKPath == "/" && XcrunPath &&
+          getVFS().exists(XcrunPath.value() + "/usr/include/sys/types.h")) {
+        foundSDKPath = XcrunPath.value();
+      }
+    }
+
+    if (foundSDKPath != "/") {
+      Args.append(Args.MakeSeparateArg(
+          nullptr, Opts.getOption(options::OPT_isysroot), foundSDKPath));
+    }
   }
 
   // Read the SDKSettings.json file for more information, like the SDK version
diff --git a/clang/lib/Lex/InitHeaderSearch.cpp b/clang/lib/Lex/InitHeaderSearch.cpp
index 2218db15013d..d05cfa38e4fb 100644
--- a/clang/lib/Lex/InitHeaderSearch.cpp
+++ b/clang/lib/Lex/InitHeaderSearch.cpp
@@ -24,6 +24,7 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/Process.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/Triple.h"
 #include <optional>
@@ -210,7 +211,10 @@ void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
       [[fallthrough]];
     default:
       // FIXME: temporary hack: hard-coded paths.
-      AddPath("/usr/local/include", System, false);
+      std::optional<std::string> CondaBuildSysrootValue =
+              llvm::sys::Process::GetEnv("CONDA_BUILD_SYSROOT");
+      if (!CondaBuildSysrootValue.has_value())
+        AddPath("/usr/local/include", System, false);
       break;
     }
   }