Support HEX_32 when building shared objects

[sidneym]

Summary

Support HEX_32 when building shared objects.

The following code:

int foo = 10; 
int *b = &foo;

will create a R_HEX_32 relocation and currently will produce the following error:
"ld.lld: error: relocation R_HEX_32 cannot be used against symbol var; recompile with -fPIC"

Hexagon didn't support this when building shared objects. This patch adds the feature and updates the testcase.

[ruiu]

LGTM

lld/trunk/ELF/Arch/Hexagon.cpp

 
 namespace {
 class Hexagon final : public TargetInfo {
 public:
   Hexagon();
   uint32_t calcEFlags() const override;
   RelExpr getRelExpr(RelType type, const Symbol &s,
                      const uint8_t *loc) const override;
+  RelType getDynRel(RelType type) const override;
   void relocateOne(uint8_t *loc, RelType type, uint64_t val) const override;
   void writePltHeader(uint8_t *buf) const override;
   void writePlt(uint8_t *buf, uint64_t gotPltEntryAddr, uint64_t pltEntryAddr,
                 int32_t index, unsigned relOff) const override;
 };
 } // namespace
 
 Hexagon::Hexagon() {
const uint8_t inst[] = {
       0x00, 0xc0, 0x9c, 0x52, // jumpr r28
   };
   memcpy(buf, inst, sizeof(inst));
 
   relocateOne(buf, R_HEX_B32_PCREL_X, gotPltEntryAddr - pltEntryAddr);
   relocateOne(buf + 4, R_HEX_6_PCREL_X, gotPltEntryAddr - pltEntryAddr);
 }
 
+RelType Hexagon::getDynRel(RelType type) const {
+  if (type == R_HEX_32)
+    return type;
+  return R_HEX_NONE;
+}
+
 TargetInfo *elf::getHexagonTargetInfo() {
   static Hexagon target;
   return ⌖
 }

lld/trunk/test/ELF/hexagon-shared.s

 # REQUIRES: hexagon
 # RUN: llvm-mc -filetype=obj -triple=hexagon-unknown-elf %s -o %t
 # RUN: llvm-mc -filetype=obj -triple=hexagon-unknown-elf %S/Inputs/hexagon-shared.s -o %t2.o
 # RUN: ld.lld -shared %t2.o -soname %t3.so -o %t3.so
 # RUN: ld.lld -shared %t %t3.so -soname %t4.so -o %t4.so
 # RUN: llvm-objdump -d -j .plt %t4.so | FileCheck --check-prefix=PLT %s
 # RUN: llvm-objdump -d -j .text %t4.so | FileCheck --check-prefix=TEXT %s
 # RUN: llvm-objdump -D -j .got %t4.so | FileCheck --check-prefix=GOT %s
+# RUN: llvm-readelf -r  %t4.so | FileCheck --check-prefix=RELO %s
 
 .global foo
 foo:
 
 # _HEX_32_PCREL
 .word _DYNAMIC - .
 call ##bar
 
 # R_HEX_PLT_B22_PCREL
 call bar@PLT
 
 # R_HEX_GOT_11_X and R_HEX_GOT_32_6_X
 r2=add(pc,##_GLOBAL_OFFSET_TABLE_@PCREL)
 r0 = memw (r2+##bar@GOT)
 jumpr r0
 
 # R_HEX_GOT_16_X
 r0 = add(r1,##bar@GOT)
 
+# R_HEX_32
+.data
+.global var
+.type var,@object
+.p2align 2
+var:
+   .word 10
+   .size var, 4
+.global pvar
+.type pvar,@object
+pvar:
+   .word var
+   .size pvar, 4
+
 # PLT: { immext(#131008
-# PLT: r28 = add(pc,##131024) }
+# PLT: r28 = add(pc,##131032) }
 # PLT: { r14 -= add(r28,#16)
 # PLT: r15 = memw(r28+#8)
 # PLT: r28 = memw(r28+#4) }
 # PLT: { r14 = asr(r14,#2)
 # PLT: jumpr r28 }
 # PLT: { trap0(#219) }
 # PLT: immext(#131008)
-# PLT: r14 = add(pc,##131008) }
+# PLT: r14 = add(pc,##131016) }
 # PLT: r28 = memw(r14+#0) }
 # PLT: jumpr r28 }
 
 # TEXT:  10000: 00 00 01 00 00010000
 # TEXT: {   call 0x10050 }
-# TEXT: r0 = add(r1,##-65408) }
+# TEXT: r0 = add(r1,##-65416) }
 
 # GOT: .got:
 # GOT: 20080: 00 00 00 00 00000000 <unknown>
+
+# RELO: 00020080  00000121 R_HEX_GLOB_DAT
+# RELO: 00030004  00000406 R_HEX_32
+# RELO: 00030018  00000122 R_HEX_JMP_SLOT