Revert "[AMDGPU] Emit read-only data to .rodata for hsa"

This reverts commit r276298.

Data stored in .rodata can have a negative offset from .text, but we
don't support negative values in relocations yet.

This caused a regression in one of the amp conformance tests:
5_Data_Cont/5_2_a_v/5_2_3_m/Assignment/Test.02.01

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276498 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/AMDGPU/AMDGPUTargetObjectFile.cpp

@@ -24,8 +24,7 @@ MCSection *AMDGPUTargetObjectFile::SelectSectionForGlobal(const GlobalValue *GV,
                                                           SectionKind Kind,
                                                           Mangler &Mang,
                                                 const TargetMachine &TM) const {
-  if (Kind.isReadOnly() && AMDGPU::isReadOnlySegment(GV) &&
-      TM.getTargetTriple().getOS() != Triple::AMDHSA)
+  if (Kind.isReadOnly() && AMDGPU::isReadOnlySegment(GV))
     return TextSection;
 
   return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang, TM);

test/CodeGen/AMDGPU/global-constant.ll

@@ -12,7 +12,7 @@
 ; GCN-NEXT: s_add_u32 s{{[0-9]+}}, s[[PC1_LO]], readonly
 ; GCN: s_addc_u32 s{{[0-9]+}}, s[[PC1_HI]], 0
 ; NOHSA: .text
-; HSA: .section .rodata
+; HSA: .text
 ; GCN: readonly:
 ; GCN: readonly2:
 define void @main(i32 %index, float addrspace(1)* %out) {

test/CodeGen/AMDGPU/hsa-globals.ll

@@ -38,7 +38,7 @@ define void @test() {
 ; ASM: .size external_global_program, 4
 
 ; ASM: .type internal_readonly,@object
-; ASM: .section .rodata.cst4,"aM",@progbits,4
+; ASM: .text
 ; ASM: internal_readonly:
 ; ASM: .long 0
 ; ASM: .size internal_readonly, 4