[clang] 58817a0 - [clang][XCOFF] Indicate that XCOFF does not support COMDATs

[David Tenty via cfe-commits]

Author: David Tenty
Date: 2020-02-18T16:10:11-05:00
New Revision: 58817a0783ca405cd36a312c7ee80e061d1cecc5

URL: https://github.com/llvm/llvm-project/commit/58817a0783ca405cd36a312c7ee80e061d1cecc5
DIFF: https://github.com/llvm/llvm-project/commit/58817a0783ca405cd36a312c7ee80e061d1cecc5.diff

LOG: [clang][XCOFF] Indicate that XCOFF does not support COMDATs

Summary: XCOFF doesn't support COMDATs, so clang shouldn't emit them.

Reviewers: stevewan, sfertile, Xiangling_L

Reviewed By: sfertile

Subscribers: dschuff, aheejin, dexonsmith, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D74631

Added: 
    clang/test/CodeGen/xcoff-comdat.cpp

Modified: 
    llvm/docs/LangRef.rst
    llvm/include/llvm/ADT/Triple.h

Removed: 
    


################################################################################
diff  --git a/clang/test/CodeGen/xcoff-comdat.cpp b/clang/test/CodeGen/xcoff-comdat.cpp
new file mode 100644
index 000000000000..7da8d9a2cc22
--- /dev/null
+++ b/clang/test/CodeGen/xcoff-comdat.cpp
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -triple powerpc-ibm-aix -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple powerpc64-ibm-aix -emit-llvm -o - %s | FileCheck %s
+
+class a {
+  virtual void d() {}
+  virtual void e();
+};
+void a::e() {}
+
+// CHECK-NOT: = comdat

diff  --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 2a61e0b19987..d14853a4e0d5 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -910,8 +910,8 @@ The selection kind must be one of the following:
     The linker may choose any COMDAT key but the sections must contain the
     same amount of data.
 
-Note that the Mach-O platform doesn't support COMDATs, and ELF and WebAssembly
-only support ``any`` as a selection kind.
+Note that XCOFF and the Mach-O platform don't support COMDATs, and ELF and
+WebAssembly only support ``any`` as a selection kind.
 
 Here is an example of a COMDAT group where a function will only be selected if
 the COMDAT key's section is the largest:

diff  --git a/llvm/include/llvm/ADT/Triple.h b/llvm/include/llvm/ADT/Triple.h
index 76a754d671fb..64ba8d7e21e4 100644
--- a/llvm/include/llvm/ADT/Triple.h
+++ b/llvm/include/llvm/ADT/Triple.h
@@ -743,7 +743,7 @@ class Triple {
 
   /// Tests whether the target supports comdat
   bool supportsCOMDAT() const {
-    return !isOSBinFormatMachO();
+    return !(isOSBinFormatMachO() || isOSBinFormatXCOFF());
   }
 
   /// Tests whether the target uses emulated TLS as default.