From f463709d7d66239b2221c48ee907b826136f84b5 Mon Sep 17 00:00:00 2001
From: Simon Atanasyan <simon@atanasyan.com>
Date: Wed, 20 Jul 2016 20:15:24 +0000
Subject: [PATCH] [ELF][MIPS] Pick arch flag from the first input file.

LLD still does not produce a correct combination of MIPS ELF flags if
input files have different sets of ELF flags (i.e. EF_MIPS_ARCH_32 and
EF_MIPS_ARCH_32R2). But now we do not stick to "R2" ABI version and can
emit EF_MIPS_ARCH_32R6 for example.

llvm-svn: 276172
---
 lld/ELF/Writer.cpp            | 26 ++++++++++++++++----------
 lld/test/ELF/basic-mips.s     |  2 +-
 lld/test/ELF/emulation.s      |  8 ++++----
 lld/test/ELF/mips-elf-flags.s | 24 ++++++++++++++++++++++--
 4 files changed, 43 insertions(+), 17 deletions(-)

diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 764699f17e20..ceff38c4e68b 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -1166,16 +1166,22 @@ template <class ELFT> void Writer<ELFT>::setPhdrs() {
   }
 }
 
-static uint32_t getMipsEFlags(bool Is64Bits) {
-  // FIXME: In fact ELF flags depends on ELF flags of input object files
-  // and selected emulation. For now just use hard coded values.
+template <class ELFT>
+static uint32_t getMipsEFlags(bool Is64Bits,
+                              const ELFFileBase<ELFT> &FirstElf) {
+  // FIXME: ELF flags depends on ELF flags of all input object files and
+  // selected emulation. For now pick the arch flag from the fisrt input file
+  // and use hard coded values for other flags.
+  uint32_t FirstElfFlags = FirstElf.getObj().getHeader()->e_flags;
+  uint32_t ElfFlags = FirstElfFlags & EF_MIPS_ARCH;
   if (Is64Bits)
-    return EF_MIPS_CPIC | EF_MIPS_PIC | EF_MIPS_ARCH_64R2;
-
-  uint32_t V = EF_MIPS_CPIC | EF_MIPS_ABI_O32 | EF_MIPS_ARCH_32R2;
-  if (Config->Shared)
-    V |= EF_MIPS_PIC;
-  return V;
+    ElfFlags |= EF_MIPS_CPIC | EF_MIPS_PIC;
+  else {
+    ElfFlags |= EF_MIPS_CPIC | EF_MIPS_ABI_O32;
+    if (Config->Shared)
+      ElfFlags |= EF_MIPS_PIC;
+  }
+  return ElfFlags;
 }
 
 template <class ELFT> static typename ELFT::uint getEntryAddr() {
@@ -1252,7 +1258,7 @@ template <class ELFT> void Writer<ELFT>::writeHeader() {
   EHdr->e_shstrndx = Out<ELFT>::ShStrTab->SectionIndex;
 
   if (Config->EMachine == EM_MIPS)
-    EHdr->e_flags = getMipsEFlags(ELFT::Is64Bits);
+    EHdr->e_flags = getMipsEFlags(ELFT::Is64Bits, FirstObj);
 
   if (!Config->Relocatable) {
     EHdr->e_phoff = sizeof(Elf_Ehdr);
diff --git a/lld/test/ELF/basic-mips.s b/lld/test/ELF/basic-mips.s
index c598c7b5f2f7..86dd04200533 100644
--- a/lld/test/ELF/basic-mips.s
+++ b/lld/test/ELF/basic-mips.s
@@ -30,7 +30,7 @@ __start:
 # CHECK-NEXT:   SectionHeaderOffset: 0x30088
 # CHECK-NEXT:   Flags [
 # CHECK-NEXT:     EF_MIPS_ABI_O32
-# CHECK-NEXT:     EF_MIPS_ARCH_32R2
+# CHECK-NEXT:     EF_MIPS_ARCH_32
 # CHECK-NEXT:     EF_MIPS_CPIC
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 52
diff --git a/lld/test/ELF/emulation.s b/lld/test/ELF/emulation.s
index 7cc764fc6c18..1d95b56d1a45 100644
--- a/lld/test/ELF/emulation.s
+++ b/lld/test/ELF/emulation.s
@@ -176,7 +176,7 @@
 # MIPS-NEXT:   SectionHeaderOffset:
 # MIPS-NEXT:   Flags [
 # MIPS-NEXT:     EF_MIPS_ABI_O32
-# MIPS-NEXT:     EF_MIPS_ARCH_32R2
+# MIPS-NEXT:     EF_MIPS_ARCH_32
 # MIPS-NEXT:     EF_MIPS_CPIC
 # MIPS-NEXT:   ]
 
@@ -205,7 +205,7 @@
 # MIPSEL-NEXT:   SectionHeaderOffset:
 # MIPSEL-NEXT:   Flags [
 # MIPSEL-NEXT:     EF_MIPS_ABI_O32
-# MIPSEL-NEXT:     EF_MIPS_ARCH_32R2
+# MIPSEL-NEXT:     EF_MIPS_ARCH_32
 # MIPSEL-NEXT:     EF_MIPS_CPIC
 # MIPSEL-NEXT:   ]
 
@@ -231,7 +231,7 @@
 # MIPS64-NEXT:   ProgramHeaderOffset: 0x40
 # MIPS64-NEXT:   SectionHeaderOffset:
 # MIPS64-NEXT:   Flags [
-# MIPS64-NEXT:     EF_MIPS_ARCH_64R2
+# MIPS64-NEXT:     EF_MIPS_ARCH_64
 # MIPS64-NEXT:     EF_MIPS_CPIC
 # MIPS64-NEXT:     EF_MIPS_PIC
 # MIPS64-NEXT:   ]
@@ -258,7 +258,7 @@
 # MIPS64EL-NEXT:   ProgramHeaderOffset: 0x40
 # MIPS64EL-NEXT:   SectionHeaderOffset:
 # MIPS64EL-NEXT:   Flags [
-# MIPS64EL-NEXT:     EF_MIPS_ARCH_64R2
+# MIPS64EL-NEXT:     EF_MIPS_ARCH_64
 # MIPS64EL-NEXT:     EF_MIPS_CPIC
 # MIPS64EL-NEXT:     EF_MIPS_PIC
 # MIPS64EL-NEXT:   ]
diff --git a/lld/test/ELF/mips-elf-flags.s b/lld/test/ELF/mips-elf-flags.s
index 7817e58b5383..c71e2b181cc8 100644
--- a/lld/test/ELF/mips-elf-flags.s
+++ b/lld/test/ELF/mips-elf-flags.s
@@ -5,6 +5,14 @@
 # RUN: llvm-readobj -h %t.so | FileCheck -check-prefix=SO %s
 # RUN: ld.lld %t.o -o %t.exe
 # RUN: llvm-readobj -h %t.exe | FileCheck -check-prefix=EXE %s
+# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux \
+# RUN:         -mcpu=mips32r2 %s -o %t-r2.o
+# RUN: ld.lld %t-r2.o -o %t-r2.exe
+# RUN: llvm-readobj -h %t-r2.exe | FileCheck -check-prefix=EXE-R2 %s
+# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux \
+# RUN:         -mcpu=mips32r6 %s -o %t-r6.o
+# RUN: ld.lld %t-r6.o -o %t-r6.exe
+# RUN: llvm-readobj -h %t-r6.exe | FileCheck -check-prefix=EXE-R6 %s
 
 # REQUIRES: mips
 
@@ -15,13 +23,25 @@ __start:
 
 # SO:      Flags [
 # SO-NEXT:   EF_MIPS_ABI_O32
-# SO-NEXT:   EF_MIPS_ARCH_32R2
+# SO-NEXT:   EF_MIPS_ARCH_32
 # SO-NEXT:   EF_MIPS_CPIC
 # SO-NEXT:   EF_MIPS_PIC
 # SO-NEXT: ]
 
 # EXE:      Flags [
 # EXE-NEXT:   EF_MIPS_ABI_O32
-# EXE-NEXT:   EF_MIPS_ARCH_32R2
+# EXE-NEXT:   EF_MIPS_ARCH_32
 # EXE-NEXT:   EF_MIPS_CPIC
 # EXE-NEXT: ]
+
+# EXE-R2:      Flags [
+# EXE-R2-NEXT:   EF_MIPS_ABI_O32
+# EXE-R2-NEXT:   EF_MIPS_ARCH_32R2
+# EXE-R2-NEXT:   EF_MIPS_CPIC
+# EXE-R2-NEXT: ]
+
+# EXE-R6:      Flags [
+# EXE-R6-NEXT:   EF_MIPS_ABI_O32
+# EXE-R6-NEXT:   EF_MIPS_ARCH_32R6
+# EXE-R6-NEXT:   EF_MIPS_CPIC
+# EXE-R6-NEXT: ]
-- 
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