IR: Add COMDATs to the IR

This new IR facility allows us to represent the object-file semantic of
a COMDAT group.

COMDATs allow us to tie together sections and make the inclusion of one
dependent on another. This is required to implement features like MS
ABI VFTables and optimizing away certain kinds of initialization in C++.

This functionality is only representable in COFF and ELF, Mach-O has no
similar mechanism.

Differential Revision: http://reviews.llvm.org/D4178

llvm-svn: 211920

7 files changed, 294 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/coff-comdat.ll b/llvm/test/CodeGen/X86/coff-comdat.ll
new file mode 100644
index 00000000000..bf27b2fff1f
--- /dev/null
+++ b/llvm/test/CodeGen/X86/coff-comdat.ll
@@ -0,0 +1,92 @@
+; RUN: llc -mtriple i386-pc-win32 < %s | FileCheck %s
+
+$f1 = comdat any
+@v1 = global i32 0, comdat $f1
+define void @f1() comdat $f1 {
+  ret void
+}
+
+$f2 = comdat exactmatch
+@v2 = global i32 0, comdat $f2
+define void @f2() comdat $f2 {
+  ret void
+}
+
+$f3 = comdat largest
+@v3 = global i32 0, comdat $f3
+define void @f3() comdat $f3 {
+  ret void
+}
+
+$f4 = comdat noduplicates
+@v4 = global i32 0, comdat $f4
+define void @f4() comdat $f4 {
+  ret void
+}
+
+$f5 = comdat samesize
+@v5 = global i32 0, comdat $f5
+define void @f5() comdat $f5 {
+  ret void
+}
+
+$f6 = comdat samesize
+@v6 = global i32 0, comdat $f6
+@f6 = global i32 0, comdat $f6
+
+$"\01@f7@0" = comdat any
+define x86_fastcallcc void @"\01@v7@0"() comdat $"\01@f7@0" {
+  ret void
+}
+define x86_fastcallcc void @"\01@f7@0"() comdat $"\01@f7@0" {
+  ret void
+}
+
+$f8 = comdat any
+define x86_fastcallcc void @v8() comdat $f8 {
+  ret void
+}
+define x86_fastcallcc void @f8() comdat $f8 {
+  ret void
+}
+
+$vftable = comdat largest
+
+@some_name = private unnamed_addr constant [2 x i8*] zeroinitializer, comdat $vftable
+@vftable = alias getelementptr([2 x i8*]* @some_name, i32 0, i32 1)
+
+; CHECK: .section        .text,"xr",discard,_f1
+; CHECK: .globl  _f1
+; CHECK: .section        .text,"xr",same_contents,_f2
+; CHECK: .globl  _f2
+; CHECK: .section        .text,"xr",largest,_f3
+; CHECK: .globl  _f3
+; CHECK: .section        .text,"xr",one_only,_f4
+; CHECK: .globl  _f4
+; CHECK: .section        .text,"xr",same_size,_f5
+; CHECK: .globl  _f5
+; CHECK: .section        .text,"xr",associative,@f7@0
+; CHECK: .globl  @v7@0
+; CHECK: .section        .text,"xr",discard,@f7@0
+; CHECK: .globl  @f7@0
+; CHECK: .section        .text,"xr",associative,@f8@0
+; CHECK: .globl  @v8@0
+; CHECK: .section        .text,"xr",discard,@f8@0
+; CHECK: .globl  @f8@0
+; CHECK: .section        .bss,"bw",associative,_f1
+; CHECK: .globl  _v1
+; CHECK: .section        .bss,"bw",associative,_f2
+; CHECK: .globl  _v2
+; CHECK: .section        .bss,"bw",associative,_f3
+; CHECK: .globl  _v3
+; CHECK: .section        .bss,"bw",associative,_f4
+; CHECK: .globl  _v4
+; CHECK: .section        .bss,"bw",associative,_f5
+; CHECK: .globl  _v5
+; CHECK: .section        .bss,"bw",associative,_f6
+; CHECK: .globl  _v6
+; CHECK: .section        .bss,"bw",same_size,_f6
+; CHECK: .globl  _f6
+; CHECK: .section        .rdata,"rd",largest,_vftable
+; CHECK: .globl  _vftable
+; CHECK: _vftable = L_some_name+4
diff --git a/llvm/test/CodeGen/X86/coff-comdat.s b/llvm/test/CodeGen/X86/coff-comdat.s
new file mode 100644
index 00000000000..aca0488c47a
--- /dev/null
+++ b/llvm/test/CodeGen/X86/coff-comdat.s
@@ -0,0 +1,156 @@
+	.text
+	.def	 @feat.00;
+	.scl	3;
+	.type	0;
+	.endef
+	.globl	@feat.00
+@feat.00 = 1
+	.def	 _f1;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",discard,_f1
+	.globl	_f1
+	.align	16, 0x90
+_f1:                                    # @f1
+# BB#0:
+	retl
+
+	.def	 _f2;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",same_contents,_f2
+	.globl	_f2
+	.align	16, 0x90
+_f2:                                    # @f2
+# BB#0:
+	retl
+
+	.def	 _f3;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",largest,_f3
+	.globl	_f3
+	.align	16, 0x90
+_f3:                                    # @f3
+# BB#0:
+	retl
+
+	.def	 _f4;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",one_only,_f4
+	.globl	_f4
+	.align	16, 0x90
+_f4:                                    # @f4
+# BB#0:
+	retl
+
+	.def	 _f5;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",same_size,_f5
+	.globl	_f5
+	.align	16, 0x90
+_f5:                                    # @f5
+# BB#0:
+	retl
+
+	.def	 @v7@0;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",associative,@f7@0
+	.globl	@v7@0
+	.align	16, 0x90
+@v7@0:                                  # @"\01@v7@0"
+# BB#0:
+	retl
+
+	.def	 @f7@0;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",discard,@f7@0
+	.globl	@f7@0
+	.align	16, 0x90
+@f7@0:                                  # @"\01@f7@0"
+# BB#0:
+	retl
+
+	.def	 @v8@0;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",associative,@f8@0
+	.globl	@v8@0
+	.align	16, 0x90
+@v8@0:                                  # @v8
+# BB#0:
+	retl
+
+	.def	 @f8@0;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",discard,@f8@0
+	.globl	@f8@0
+	.align	16, 0x90
+@f8@0:                                  # @f8
+# BB#0:
+	retl
+
+	.section	.bss,"bw",associative,_f1
+	.globl	_v1                     # @v1
+	.align	4
+_v1:
+	.long	0                       # 0x0
+
+	.section	.bss,"bw",associative,_f2
+	.globl	_v2                     # @v2
+	.align	4
+_v2:
+	.long	0                       # 0x0
+
+	.section	.bss,"bw",associative,_f3
+	.globl	_v3                     # @v3
+	.align	4
+_v3:
+	.long	0                       # 0x0
+
+	.section	.bss,"bw",associative,_f4
+	.globl	_v4                     # @v4
+	.align	4
+_v4:
+	.long	0                       # 0x0
+
+	.section	.bss,"bw",associative,_f5
+	.globl	_v5                     # @v5
+	.align	4
+_v5:
+	.long	0                       # 0x0
+
+	.section	.bss,"bw",associative,_f6
+	.globl	_v6                     # @v6
+	.align	4
+_v6:
+	.long	0                       # 0x0
+
+	.section	.bss,"bw",same_size,_f6
+	.globl	_f6                     # @f6
+	.align	4
+_f6:
+	.long	0                       # 0x0
+
+	.section	.rdata,"rd"
+	.align	4                       # @some_name
+L_some_name:
+	.zero	8
+
+
+	.globl	_vftable
+_vftable = L_some_name+4
diff --git a/llvm/test/CodeGen/X86/coff-comdat2.ll b/llvm/test/CodeGen/X86/coff-comdat2.ll
new file mode 100644
index 00000000000..6744b5b02ad
--- /dev/null
+++ b/llvm/test/CodeGen/X86/coff-comdat2.ll
@@ -0,0 +1,9 @@
+; RUN: not llc %s -o /dev/null 2>&1 | FileCheck %s
+
+target datalayout = "e-m:w-p:32:32-i64:64-f80:32-n8:16:32-S32"
+target triple = "i686-pc-windows-msvc"
+
+$foo = comdat largest
+@foo = global i32 0
+@bar = global i32 0, comdat $foo
+; CHECK: Associative COMDAT symbol 'foo' is not a key for it's COMDAT.
diff --git a/llvm/test/CodeGen/X86/coff-comdat3.ll b/llvm/test/CodeGen/X86/coff-comdat3.ll
new file mode 100644
index 00000000000..76e464b2754
--- /dev/null
+++ b/llvm/test/CodeGen/X86/coff-comdat3.ll
@@ -0,0 +1,8 @@
+; RUN: not llc %s -o /dev/null 2>&1 | FileCheck %s
+
+target datalayout = "e-m:w-p:32:32-i64:64-f80:32-n8:16:32-S32"
+target triple = "i686-pc-windows-msvc"
+
+$foo = comdat largest
+@bar = global i32 0, comdat $foo
+; CHECK: Associative COMDAT symbol 'foo' does not exist.
diff --git a/llvm/test/CodeGen/X86/elf-comdat.ll b/llvm/test/CodeGen/X86/elf-comdat.ll
new file mode 100644
index 00000000000..c7e6df7d64f
--- /dev/null
+++ b/llvm/test/CodeGen/X86/elf-comdat.ll
@@ -0,0 +1,11 @@
+; RUN: llc -mtriple x86_64-pc-linux-gnu < %s | FileCheck %s
+
+$f = comdat any
+@v = global i32 0, comdat $f
+define void @f() comdat $f {
+  ret void
+}
+; CHECK: .section        .text.f,"axG",@progbits,f,comdat
+; CHECK: .globl  f
+; CHECK: .section        .bss.v,"aGw",@nobits,f,comdat
+; CHECK: .globl  v
diff --git a/llvm/test/CodeGen/X86/elf-comdat2.ll b/llvm/test/CodeGen/X86/elf-comdat2.ll
new file mode 100644
index 00000000000..209da39ed88
--- /dev/null
+++ b/llvm/test/CodeGen/X86/elf-comdat2.ll
@@ -0,0 +1,12 @@
+; RUN: llc -mtriple x86_64-pc-linux-gnu < %s | FileCheck %s
+
+$foo = comdat any
+@bar = global i32 42, comdat $foo
+@foo = global i32 42
+
+; CHECK:      .type   bar,@object
+; CHECK-NEXT: .section        .data.bar,"aGw",@progbits,foo,comdat
+; CHECK-NEXT: .globl  bar
+; CHECK:      .type   foo,@object
+; CHECK-NEXT: .data
+; CHECK-NEXT: .globl  foo
diff --git a/llvm/test/CodeGen/X86/macho-comdat.ll b/llvm/test/CodeGen/X86/macho-comdat.ll
new file mode 100644
index 00000000000..3c2d997b459
--- /dev/null
+++ b/llvm/test/CodeGen/X86/macho-comdat.ll
@@ -0,0 +1,6 @@
+; RUN: not llc -mtriple x86_64-apple-darwin < %s 2> %t
+; RUN: FileCheck < %t %s
+
+$f = comdat any
+@v = global i32 0, comdat $f
+; CHECK: LLVM ERROR: MachO doesn't support COMDATs, 'f' cannot be lowered.