[ELF][AMDGPU] Avoid PT_LOAD to have overlapping p_offset range

Changes introduced in commit https://llvm.org/svn/llvm-project/lld/trunk@370180
allows PT_LOAD to have overlapping p_offset ranges on EM_AMDGPU and
EM_SPARCV9. However this is introducing crash as described in internal issue
SWDEV-203875. It is disabled for AMDGPU.

Change-Id: Idf42b7ac56940bd83414fe83f0e4ae57693245e8

ELF/Writer.cpp

@@ -2242,7 +2242,9 @@ template <class ELFT> void Writer<ELFT>::fixSectionAlignments() {
       // maximum page size boundary so that we can find the ELF header at the
       // start. We cannot benefit from overlapping p_offset ranges with the
       // previous segment anyway.
-      if (config->zSeparate == SeparateSegmentKind::Loadable ||
+      bool enable = config->emachine != EM_AMDGPU;
+
+      if (!enable || config->zSeparate == SeparateSegmentKind::Loadable ||
           (config->zSeparate == SeparateSegmentKind::Code && prev &&
            (prev->p_flags & PF_X) != (p->p_flags & PF_X)) ||
           cmd->type == SHT_LLVM_PART_EHDR)

test/ELF/amdgpu-relocs.s

@@ -94,7 +94,7 @@ foo:
 # linker.
 # CHECK: Relocations [
 # CHECK: .rela.dyn {
-# CHECK-NEXT: R_AMDGPU_RELATIVE64 - 0x3928
+# CHECK-NEXT: R_AMDGPU_RELATIVE64 - 0x3008
 # CHECK-NEXT: R_AMDGPU_ABS64 common_var0 0x0
 # CHECK-NEXT: R_AMDGPU_ABS64 common_var1 0x0
 # CHECK-NEXT: R_AMDGPU_ABS64 common_var2 0x0
@@ -114,16 +114,16 @@ foo:
 # CHECK-NEXT: }
 # CHECK-NEXT: ]
 
-# NM: 0000000000003930 B common_var0
-# NM: 0000000000003d30 B common_var1
-# NM: 0000000000004130 B common_var2
-# NM: 0000000000003928 d temp2
+# NM: 0000000000003010 B common_var0
+# NM: 0000000000003410 B common_var1
+# NM: 0000000000003810 B common_var2
+# NM: 0000000000003008 d temp2
 
-# temp2 - foo = 0x3928-0x768 = 0x31c0
+# temp2 - foo = 0x3008-0x768 = 0x28a0
 # HEX:      section '.rodata':
-# HEX-NEXT: 0x00000768 c0310000 00000000
+# HEX-NEXT: 0x00000768 a0280000 00000000
 
 # common_var2+4, common_var1+8, and common_var0+12.
 # HEX:      section 'nonalloc':
-# HEX-NEXT: 0x00000000 00000000 34410000 00000000 383d0000
-# HEX-NEXT: 0x00000010 00000000 3c390000
+# HEX-NEXT: 0x00000000 00000000 14380000 00000000 18340000
+# HEX-NEXT: 0x00000010 00000000 1c300000