[MachO] Stop generating *coal* sections.

Recommit r250342: move coal-sections-powerpc.s to subdirectory for powerpc.

Some background on why we don't have to use *coal* sections anymore:
Long ago when C++ was new and "weak" had not been standardized, an attempt was
made in cctools to support C++ inlines that can be coalesced by putting them
into their own section (TEXT/textcoal_nt instead of TEXT/text).

The current macho linker supports the weak-def bit on any symbol to allow it to
be coalesced, but the compiler still puts weak-def functions/data into alternate
section names, which the linker must map back to the base section name.

This patch makes changes that are necessary to prevent the compiler from using
the "coal" sections and have it use the non-coal sections instead when the
target architecture is not powerpc:

TEXT/textcoal_nt instead use TEXT/text
TEXT/const_coal instead use TEXT/const
DATA/datacoal_nt instead use DATA/data

If the target is powerpc, we continue to use the *coal* sections since anyone
targeting powerpc is probably using an old linker that doesn't have support for
the weak-def bits.

Also, have the assembler issue a warning if it encounters a *coal* section in
the assembly file and inform the users to use the non-coal sections instead.

rdar://problem/14265330

Differential Revision: http://reviews.llvm.org/D13188

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@250370 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index 31091ef284a62782d4529bb8526eba0c7c575d77..666a1c306c5f8cf47e7791d4f4c681e5097ea7c2 100644 (file)
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -114,22 +114,37 @@ void MCObjectFileInfo::initMachOMCObjectFileInfo(Triple T) {
     = Ctx->getMachOSection("__TEXT", "__const", 0,
                            SectionKind::getReadOnly());
 
-  TextCoalSection
-    = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
-                           MachO::S_COALESCED |
-                           MachO::S_ATTR_PURE_INSTRUCTIONS,
-                           SectionKind::getText());
-  ConstTextCoalSection
-    = Ctx->getMachOSection("__TEXT", "__const_coal",
-                           MachO::S_COALESCED,
-                           SectionKind::getReadOnly());
+  // If the target is not powerpc, map the coal sections to the non-coal
+  // sections.
+  //
+  // "__TEXT/__textcoal_nt" => section "__TEXT/__text"
+  // "__TEXT/__const_coal"  => section "__TEXT/__const"
+  // "__DATA/__datacoal_nt" => section "__DATA/__data"
+  Triple::ArchType ArchTy = T.getArch();
+
+  if (ArchTy == Triple::ppc || ArchTy == Triple::ppc64) {
+    TextCoalSection
+      = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
+                             MachO::S_COALESCED |
+                             MachO::S_ATTR_PURE_INSTRUCTIONS,
+                             SectionKind::getText());
+    ConstTextCoalSection
+      = Ctx->getMachOSection("__TEXT", "__const_coal",
+                             MachO::S_COALESCED,
+                             SectionKind::getReadOnly());
+    DataCoalSection
+      = Ctx->getMachOSection("__DATA","__datacoal_nt",
+                             MachO::S_COALESCED,
+                             SectionKind::getDataRel());
+  } else {
+    TextCoalSection = TextSection;
+    ConstTextCoalSection = ReadOnlySection;
+    DataCoalSection = DataSection;
+  }
+
   ConstDataSection  // .const_data
     = Ctx->getMachOSection("__DATA", "__const", 0,
                            SectionKind::getReadOnlyWithRel());
-  DataCoalSection
-    = Ctx->getMachOSection("__DATA","__datacoal_nt",
-                           MachO::S_COALESCED,
-                           SectionKind::getDataRel());
   DataCommonSection
     = Ctx->getMachOSection("__DATA","__common",
                            MachO::S_ZEROFILL,

diff --git a/lib/MC/MCParser/DarwinAsmParser.cpp b/lib/MC/MCParser/DarwinAsmParser.cpp
index dc664e8a8f61005dacf06039127bd1890d8c1c16..5e99ad092f7d1e01a0a92d5e0f7b116ffe5aaddd 100644 (file)
--- a/lib/MC/MCParser/DarwinAsmParser.cpp
+++ b/lib/MC/MCParser/DarwinAsmParser.cpp
@@ -10,8 +10,10 @@
 #include "llvm/MC/MCParser/MCAsmParserExtension.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/Triple.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCObjectFileInfo.h"
 #include "llvm/MC/MCParser/MCAsmLexer.h"
 #include "llvm/MC/MCParser/MCAsmParser.h"
 #include "llvm/MC/MCSectionMachO.h"
@@ -579,6 +581,29 @@ bool DarwinAsmParser::parseDirectiveSection(StringRef, SMLoc) {
   if (!ErrorStr.empty())
     return Error(Loc, ErrorStr.c_str());
 
+  // Issue a warning if the target is not powerpc and Section is a *coal* section.
+  Triple TT = getParser().getContext().getObjectFileInfo()->getTargetTriple();
+  Triple::ArchType ArchTy = TT.getArch();
+
+  if (ArchTy != Triple::ppc && ArchTy != Triple::ppc64) {
+    StringRef NonCoalSection = StringSwitch<StringRef>(Section)
+                                   .Case("__textcoal_nt", "__text")
+                                   .Case("__const_coal", "__const")
+                                   .Case("__datacoal_nt", "__data")
+                                   .Default(Section);
+
+    if (!Section.equals(NonCoalSection)) {
+      StringRef SectionVal(Loc.getPointer());
+      size_t B = SectionVal.find(',') + 1, E = SectionVal.find(',', B);
+      SMLoc BLoc = SMLoc::getFromPointer(SectionVal.data() + B);
+      SMLoc ELoc = SMLoc::getFromPointer(SectionVal.data() + E);
+      getParser().Warning(Loc, "section \"" + Section + "\" is deprecated",
+                          SMRange(BLoc, ELoc));
+      getParser().Note(Loc, "change section name to \"" + NonCoalSection +
+                       "\"", SMRange(BLoc, ELoc));
+    }
+  }
+
   // FIXME: Arch specific.
   bool isText = Segment == "__TEXT";  // FIXME: Hack.
   getStreamer().SwitchSection(getContext().getMachOSection(

diff --git a/test/CodeGen/PowerPC/coal-sections.ll b/test/CodeGen/PowerPC/coal-sections.ll
new file mode 100644 (file)
index 0000000..377891c
--- /dev/null
+++ b/test/CodeGen/PowerPC/coal-sections.ll
@@ -0,0 +1,24 @@
+; RUN: llc < %s -mtriple powerpc-apple-darwin8 -march=ppc32 | FileCheck %s
+
+; Check that *coal* sections are emitted.
+
+; CHECK: .section  __TEXT,__textcoal_nt,coalesced,pure_instructions
+; CHECK: .section  __TEXT,__textcoal_nt,coalesced,pure_instructions
+; CHECK-NEXT: .globl  _foo
+
+; CHECK: .section  __TEXT,__const_coal,coalesced
+; CHECK-NEXT: .globl  _a
+
+; CHECK: .section  __DATA,__datacoal_nt,coalesced
+; CHECK-NEXT: .globl  _b
+
+@a = weak_odr constant [4 x i32] [i32 1, i32 2, i32 3, i32 4], align 16
+@b = weak global i32 5, align 4
+@g = common global i32* null, align 8
+
+; Function Attrs: nounwind ssp uwtable
+define weak i32* @foo() {
+entry:
+  store i32* getelementptr inbounds ([4 x i32], [4 x i32]* @a, i64 0, i64 0), i32** @g, align 8
+  ret i32* @b
+}

diff --git a/test/CodeGen/X86/coal-sections.ll b/test/CodeGen/X86/coal-sections.ll
new file mode 100644 (file)
index 0000000..05b2a8c
--- /dev/null
+++ b/test/CodeGen/X86/coal-sections.ll
@@ -0,0 +1,23 @@
+; RUN: llc < %s -mtriple x86_64-apple-darwin | FileCheck %s
+
+; Check that *coal* sections are not emitted.
+
+; CHECK: .section  __TEXT,__text,regular,pure_instructions{{$}}
+; CHECK-NEXT: .globl  _foo
+
+; CHECK: .section  __TEXT,__const{{$}}
+; CHECK-NEXT: .globl  _a
+
+; CHECK: .section  __DATA,__data{{$}}
+; CHECK-NEXT: .globl  _b
+
+@a = weak_odr constant [4 x i32] [i32 1, i32 2, i32 3, i32 4], align 16
+@b = weak global i32 5, align 4
+@g = common global i32* null, align 8
+
+; Function Attrs: nounwind ssp uwtable
+define weak i32* @foo() {
+entry:
+  store i32* getelementptr inbounds ([4 x i32], [4 x i32]* @a, i64 0, i64 0), i32** @g, align 8
+  ret i32* @b
+}

diff --git a/test/CodeGen/X86/global-sections.ll b/test/CodeGen/X86/global-sections.ll
index 82547a6067429412d507bbac0dfcd36b03dadd26..92440f2b33160f9e9b25995858644761a73358bd 100644 (file)
--- a/test/CodeGen/X86/global-sections.ll
+++ b/test/CodeGen/X86/global-sections.ll
@@ -117,7 +117,7 @@ bb7:
 
 ; TODO: linux drops this into .rodata, we drop it into ".gnu.linkonce.r.G2"
 
-; DARWIN: .section __TEXT,__const_coal,coalesced
+; DARWIN: .section __TEXT,__const{{$}}
 ; DARWIN: _G2:
 ; DARWIN:    .long 42
 
@@ -176,7 +176,6 @@ bb7:
 ; LINUX: .weak  "foo bar"
 ; LINUX: "foo bar":
 
-; DARWIN: .section              __DATA,__datacoal_nt,coalesced
 ; DARWIN: .globl        "_foo bar"
 ; DARWIN:       .weak_definition "_foo bar"
 ; DARWIN: "_foo bar":
@@ -190,7 +189,7 @@ bb7:
 ; LINUX:   .byte        1
 ; LINUX:   .size        G6, 1
 
-; DARWIN:  .section __TEXT,__const_coal,coalesced
+; DARWIN:  .section __TEXT,__const{{$}}
 ; DARWIN:  .globl _G6
 ; DARWIN:  .weak_definition _G6
 ; DARWIN:_G6:
@@ -239,7 +238,7 @@ bb7:
 @G10 = weak global [100 x i32] zeroinitializer, align 32 ; <[100 x i32]*> [#uses=0]
 
 
-; DARWIN:       .section        __DATA,__datacoal_nt,coalesced
+; DARWIN:       .section        __DATA,__data{{$}}
 ; DARWIN: .globl _G10
 ; DARWIN:       .weak_definition _G10
 ; DARWIN:       .align  5

diff --git a/test/MC/MachO/PowerPC/coal-sections-powerpc.s b/test/MC/MachO/PowerPC/coal-sections-powerpc.s
new file mode 100644 (file)
index 0000000..1c3dc37
--- /dev/null
+++ b/test/MC/MachO/PowerPC/coal-sections-powerpc.s
@@ -0,0 +1,46 @@
+// RUN: llvm-mc -triple powerpc-apple-darwin8 -arch=ppc32 -filetype=obj %s -o - | llvm-readobj -sections | FileCheck %s
+
+// CHECK: Section {
+// CHECK-NEXT: Index: 0
+
+// CHECK: Section {
+// CHECK-NEXT: Index: 1
+// CHECK-NEXT: Name: __textcoal_nt (
+
+// CHECK: Section {
+// CHECK-NEXT: Index: 2
+
+// CHECK: Section {
+// CHECK-NEXT: Index: 3
+// CHECK-NEXT: Name: __const_coal (
+
+// CHECK: Section {
+// CHECK-NEXT: Index: 4
+// CHECK-NEXT: Name: __datacoal_nt (
+
+  .section  __TEXT,__text,regular,pure_instructions
+  .machine ppc
+  .section  __TEXT,__textcoal_nt,coalesced,pure_instructions
+  .section  __TEXT,__symbol_stub1,symbol_stubs,pure_instructions,16
+  .section  __TEXT,__text,regular,pure_instructions
+  .section  __TEXT,__textcoal_nt,coalesced,pure_instructions
+  .globl  _foo
+  .weak_definition  _foo
+  .align  4
+_foo:
+       blr
+
+.subsections_via_symbols
+       .section        __TEXT,__const_coal,coalesced
+       .globl  _a                      ; @a
+       .weak_definition        _a
+       .align  4
+_a:
+       .long   1                       ; 0x1
+
+       .section        __DATA,__datacoal_nt,coalesced
+       .globl  _b                      ; @b
+       .weak_definition        _b
+       .align  2
+_b:
+       .long   5                       ; 0x5

diff --git a/test/MC/MachO/PowerPC/lit.local.cfg b/test/MC/MachO/PowerPC/lit.local.cfg
new file mode 100644 (file)
index 0000000..0913324
--- /dev/null
+++ b/test/MC/MachO/PowerPC/lit.local.cfg
@@ -0,0 +1,2 @@
+if not 'PowerPC' in config.root.targets:
+    config.unsupported = True

diff --git a/test/MC/MachO/coal-sections-x86_64.s b/test/MC/MachO/coal-sections-x86_64.s
new file mode 100644 (file)
index 0000000..5ecdc57
--- /dev/null
+++ b/test/MC/MachO/coal-sections-x86_64.s
@@ -0,0 +1,48 @@
+// RUN: llvm-mc -triple x86_64-apple-darwin -filetype=obj %s -o - 2>%t.err | llvm-readobj -sections | FileCheck %s
+// RUN: FileCheck --check-prefix=WARNING < %t.err %s
+
+// CHECK: Section {
+// CHECK-NEXT: Index: 0
+// CHECK-NEXT: Name: __text (
+
+// CHECK: Section {
+// CHECK-NEXT: Index: 1
+// CHECK-NEXT: Name: __textcoal_nt (
+
+// CHECK: Section {
+// CHECK-NEXT: Index: 2
+// CHECK-NEXT: Name: __const_coal (
+
+// CHECK: Section {
+// CHECK-NEXT: Index: 3
+// CHECK-NEXT: Name: __datacoal_nt (
+
+// WARNING: warning: section "__textcoal_nt" is deprecated
+// WARNING: note: change section name to "__text"
+// WARNING: warning: section "__const_coal" is deprecated
+// WARNING: note: change section name to "__const"
+// WARNING: warning: section "__datacoal_nt" is deprecated
+// WARNING: note: change section name to "__data"
+
+       .section        __TEXT,__textcoal_nt,coalesced,pure_instructions
+       .globl  _foo
+       .weak_definition        _foo
+       .align  4, 0x90
+_foo:
+       retq
+
+       .section        __TEXT,__const_coal,coalesced
+       .globl  _a                      ## @a
+       .weak_definition        _a
+       .align  4
+_a:
+       .long   1                       ## 0x1
+
+       .section        __DATA,__datacoal_nt,coalesced
+       .globl  _b                      ## @b
+       .weak_definition        _b
+       .align  2
+_b:
+       .long   5                       ## 0x5
+
+.subsections_via_symbols