[llvm] r204703 - WinCOFF: Add support for -fdata-sections

[David Majnemer]

Author: majnemer
Date: Tue Mar 25 01:14:26 2014
New Revision: 204703

URL: http://llvm.org/viewvc/llvm-project?rev=204703&view=rev
Log:
WinCOFF: Add support for -fdata-sections

This is a pretty straight forward translation for COFF, we just need to
stick the data in a COMDAT section marked as
IMAGE_COMDAT_SELECT_NODUPLICATES.

N.B. We must be careful to avoid sticking entities with private linkage
in COMDAT groups.  COFF is pretty hostile to the renaming of entities so
we must be careful to disallow GlobalVariables with unstable names.

Modified:
    llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
    llvm/trunk/test/CodeGen/X86/global-sections.ll

Modified: llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp?rev=204703&r1=204702&r2=204703&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp (original)
+++ llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp Tue Mar 25 01:14:26 2014
@@ -770,12 +770,18 @@ SelectSectionForGlobal(const GlobalValue
                        Mangler &Mang, const TargetMachine &TM) const {
   // If we have -ffunction-sections then we should emit the global value to a
   // uniqued section specifically for it.
-  // TODO: Implement -fdata-sections.
-  bool EmitUniquedSection = Kind.isText() && TM.getFunctionSections();
+  bool EmitUniquedSection;
+  if (Kind.isText())
+    EmitUniquedSection = TM.getFunctionSections();
+  else
+    EmitUniquedSection = TM.getDataSections();
 
   // If this global is linkonce/weak and the target handles this by emitting it
   // into a 'uniqued' section name, create and return the section now.
-  if (GV->isWeakForLinker() || EmitUniquedSection) {
+  // Section names depend on the name of the symbol which is not feasible if the
+  // symbol has private linkage.
+  if ((GV->isWeakForLinker() || EmitUniquedSection) &&
+      !GV->hasPrivateLinkage()) {
     const char *Name = getCOFFSectionNameForUniqueGlobal(Kind);
     unsigned Characteristics = getCOFFSectionFlags(Kind);
 

Modified: llvm/trunk/test/CodeGen/X86/global-sections.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/global-sections.ll?rev=204703&r1=204702&r2=204703&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/global-sections.ll (original)
+++ llvm/trunk/test/CodeGen/X86/global-sections.ll Tue Mar 25 01:14:26 2014
@@ -3,8 +3,14 @@
 ; RUN: llc < %s -mtriple=i386-apple-darwin10 -relocation-model=static | FileCheck %s -check-prefix=DARWIN-STATIC
 ; RUN: llc < %s -mtriple=x86_64-apple-darwin10 | FileCheck %s -check-prefix=DARWIN64
 ; RUN: llc < %s -mtriple=i386-unknown-linux-gnu -fdata-sections | FileCheck %s -check-prefix=LINUX-SECTIONS
-; RUN: llc < %s -mtriple=i686-pc-win32 -ffunction-sections | FileCheck %s -check-prefix=WIN32-SECTIONS
+; RUN: llc < %s -mtriple=i686-pc-win32 -fdata-sections -ffunction-sections | FileCheck %s -check-prefix=WIN32-SECTIONS
 
+define void @F1() {
+  ret void
+}
+
+; WIN32-SECTIONS: .section        .text,"xr",one_only,_F1
+; WIN32-SECTIONS: .globl _F1
 
 ; int G1;
 @G1 = common global i32 0
@@ -42,6 +48,9 @@
 ; LINUX-SECTIONS: .section        .rodata.G3,"a", at progbits
 ; LINUX-SECTIONS: .globl  G3
 
+; WIN32-SECTIONS: .section        .rdata,"r",one_only,_G3
+; WIN32-SECTIONS: .globl  _G3
+
 
 ; _Complex long long const G4 = 34;
 @G4 = unnamed_addr constant {i64,i64} { i64 34, i64 0 }
@@ -118,6 +127,9 @@
 ; LINUX-SECTIONS: .section        .rodata.G7,"aMS", at progbits,1
 ; LINUX-SECTIONS:	.globl G7
 
+; WIN32-SECTIONS: .section        .rdata,"r",one_only,_G7
+; WIN32-SECTIONS:	.globl _G7
+
 
 @G8 = unnamed_addr constant [4 x i16] [ i16 1, i16 2, i16 3, i16 0 ]
 
@@ -178,9 +190,7 @@
 ; LINUX-SECTIONS:        .asciz  "foo"
 ; LINUX-SECTIONS:        .size   .LG14, 4
 
-define void @G15() {
-  ret void
-}
+; WIN32-SECTIONS:        .section        .rdata,"r"
+; WIN32-SECTIONS: L_G14:
+; WIN32-SECTIONS:        .asciz  "foo"
 
-; WIN32-SECTIONS: .section        .text,"xr",one_only,_G15
-; WIN32-SECTIONS: .globl _G15