From fcbe17c6be86c87031822c1c01d8b43b6d142695 Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatanaka@apple.com>
Date: Wed, 28 Mar 2018 21:13:14 +0000
Subject: [ObjC++] Make parameter passing and function return compatible with
 ObjC

ObjC and ObjC++ pass non-trivial structs in a way that is incompatible
with each other. For example:

typedef struct {
  id f0;
  __weak id f1;
} S;

// this code is compiled in c++.
extern "C" {
  void foo(S s);
}

void caller() {
  // the caller passes the parameter indirectly and destructs it.
  foo(S());
}

// this function is compiled in c.
// 'a' is passed directly and is destructed in the callee.
void foo(S a) {
}

This patch fixes the incompatibility by passing and returning structs
with __strong or weak fields using the C ABI in C++ mode. __strong and
__weak fields in a struct do not cause the struct to be destructed in
the caller and __strong fields do not cause the struct to be passed
indirectly.

Also, this patch fixes the microsoft ABI bug mentioned here:

https://reviews.llvm.org/D41039?id=128767#inline-364710

rdar://problem/38887866

Differential Revision: https://reviews.llvm.org/D44908

llvm-svn: 328731
---
 clang/lib/Frontend/CompilerInvocation.cpp | 54 +++++++++++++++----------------
 1 file changed, 27 insertions(+), 27 deletions(-)

(limited to 'clang/lib/Frontend/CompilerInvocation.cpp')

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index d8bd500..84eee0e 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -633,33 +633,6 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   if (!Opts.ProfileInstrumentUsePath.empty())
     setPGOUseInstrumentor(Opts, Opts.ProfileInstrumentUsePath);
 
-  if (Arg *A = Args.getLastArg(OPT_fclang_abi_compat_EQ)) {
-    Opts.setClangABICompat(CodeGenOptions::ClangABI::Latest);
-
-    StringRef Ver = A->getValue();
-    std::pair<StringRef, StringRef> VerParts = Ver.split('.');
-    unsigned Major, Minor = 0;
-
-    // Check the version number is valid: either 3.x (0 <= x <= 9) or
-    // y or y.0 (4 <= y <= current version).
-    if (!VerParts.first.startswith("0") &&
-        !VerParts.first.getAsInteger(10, Major) &&
-        3 <= Major && Major <= CLANG_VERSION_MAJOR &&
-        (Major == 3 ? VerParts.second.size() == 1 &&
-                      !VerParts.second.getAsInteger(10, Minor)
-                    : VerParts.first.size() == Ver.size() ||
-                      VerParts.second == "0")) {
-      // Got a valid version number.
-      if (Major == 3 && Minor <= 8)
-        Opts.setClangABICompat(CodeGenOptions::ClangABI::Ver3_8);
-      else if (Major <= 4)
-        Opts.setClangABICompat(CodeGenOptions::ClangABI::Ver4);
-    } else if (Ver != "latest") {
-      Diags.Report(diag::err_drv_invalid_value)
-          << A->getAsString(Args) << A->getValue();
-    }
-  }
-
   Opts.CoverageMapping =
       Args.hasFlag(OPT_fcoverage_mapping, OPT_fno_coverage_mapping, false);
   Opts.DumpCoverageMapping = Args.hasArg(OPT_dump_coverage_mapping);
@@ -2670,6 +2643,33 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
 
   // -fallow-editor-placeholders
   Opts.AllowEditorPlaceholders = Args.hasArg(OPT_fallow_editor_placeholders);
+
+  if (Arg *A = Args.getLastArg(OPT_fclang_abi_compat_EQ)) {
+    Opts.setClangABICompat(LangOptions::ClangABI::Latest);
+
+    StringRef Ver = A->getValue();
+    std::pair<StringRef, StringRef> VerParts = Ver.split('.');
+    unsigned Major, Minor = 0;
+
+    // Check the version number is valid: either 3.x (0 <= x <= 9) or
+    // y or y.0 (4 <= y <= current version).
+    if (!VerParts.first.startswith("0") &&
+        !VerParts.first.getAsInteger(10, Major) &&
+        3 <= Major && Major <= CLANG_VERSION_MAJOR &&
+        (Major == 3 ? VerParts.second.size() == 1 &&
+                      !VerParts.second.getAsInteger(10, Minor)
+                    : VerParts.first.size() == Ver.size() ||
+                      VerParts.second == "0")) {
+      // Got a valid version number.
+      if (Major == 3 && Minor <= 8)
+        Opts.setClangABICompat(LangOptions::ClangABI::Ver3_8);
+      else if (Major <= 4)
+        Opts.setClangABICompat(LangOptions::ClangABI::Ver4);
+    } else if (Ver != "latest") {
+      Diags.Report(diag::err_drv_invalid_value)
+          << A->getAsString(Args) << A->getValue();
+    }
+  }
 }
 
 static bool isStrictlyPreprocessorAction(frontend::ActionKind Action) {
-- 
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