[PATCH] D47966: [ELF][PPC64] Add R_PPC64_DTPREL16* relocations for local-dynamic TLS model

[Fangrui Song via Phabricator via llvm-commits]

MaskRay updated this revision to Diff 150589.
MaskRay added a comment.

Test comment


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D47966

Files:
  ELF/Arch/PPC64.cpp
  test/ELF/ppc64-local-dynamic.s


Index: test/ELF/ppc64-local-dynamic.s
===================================================================
--- test/ELF/ppc64-local-dynamic.s
+++ test/ELF/ppc64-local-dynamic.s
@@ -32,6 +32,9 @@
         addi 3, 3, i at got@tlsld at l
         bl __tls_get_addr(i at tlsld)
         nop
+        addi 4, 3, i at dtprel
+        addis 4, 3, j at dtprel@ha
+        addi 4, 4, j at dtprel@l
         ld 0, 16(1)
         mtlr 0
         blr
@@ -76,6 +79,9 @@
 // InputRelocs:     R_PPC64_GOT_TLSLD16_HA 0000000000000000 i + 0
 // InputRelocs:     R_PPC64_GOT_TLSLD16_LO 0000000000000000 i + 0
 // InputRelocs:     R_PPC64_TLSLD          0000000000000000 i + 0
+// InputRelocs:     R_PPC64_DTPREL16       0000000000000000 i + 0
+// InputRelocs:     R_PPC64_DTPREL16_HA    0000000000000000 j + 0
+// InputRelocs:     R_PPC64_DTPREL16_LO    0000000000000000 j + 0
 // InputRelocs:     R_PPC64_GOT_TLSLD16_HI 0000000000000000 j + 0
 // InputRelocs:     R_PPC64_GOT_TLSLD16    0000000000000008 k + 0
 
@@ -99,9 +105,15 @@
 
 // #ha(i at got@tlsld) --> (0x20108 - 0x28100 + 0x8000) >> 16 = 0
 // #lo(i at got@tlsld) --> (0x20108 - 0x28100) = -7ff8 = -32760
+// i at dtprel --> (0x0 - 0x8000) = -32768
+// #ha(j at dtprel) --> (0x10 - 0x8000) >> 16 = 0
+// #lo(j at dtprel) --> (0x10 - 0x8000) & 0xffff = -32752
 // Dis:     test:
 // Dis:        addis 3, 2, 0
 // Dis-NEXT:   addi 3, 3, -32760
+// Dis:        addi 4, 3, -32768
+// Dis-NEXT:   addis 4, 3, 0
+// Dis-NEXT:   addi 4, 4, -32752
 
 // #hi(j at got@tlsld) --> (0x20108 - 0x28100 ) > 16 = -1
 // Dis: test_hi:
Index: ELF/Arch/PPC64.cpp
===================================================================
--- ELF/Arch/PPC64.cpp
+++ ELF/Arch/PPC64.cpp
@@ -156,6 +156,10 @@
 RelExpr PPC64::getRelExpr(RelType Type, const Symbol &S,
                           const uint8_t *Loc) const {
   switch (Type) {
+  case R_PPC64_DTPREL16:
+  case R_PPC64_DTPREL16_HA:
+  case R_PPC64_DTPREL16_LO:
+    return R_ABS;
   case R_PPC64_TOC16:
   case R_PPC64_TOC16_DS:
   case R_PPC64_TOC16_HA:
@@ -232,25 +236,33 @@
 }
 
 static std::pair<RelType, uint64_t> toAddr16Rel(RelType Type, uint64_t Val) {
+  // For R_PPC64_DTPREL16* relocations, DTV pointer points 0x8000 bytes past the
+  // start of each TLS block. We also subtract 0x8000 (which equals to
+  // PPC64TocOffset) from Val to calculate the offset and thus can use the same
+  // formula.
   uint64_t V = Val - PPC64TocOffset;
   switch (Type) {
+  case R_PPC64_DTPREL16:
   case R_PPC64_GOT_TLSGD16:
   case R_PPC64_GOT_TLSLD16:
   case R_PPC64_TOC16:
     return {R_PPC64_ADDR16, V};
   case R_PPC64_TOC16_DS:
   case R_PPC64_GOT_TPREL16_DS:
     return {R_PPC64_ADDR16_DS, V};
+  case R_PPC64_DTPREL16_HA:
   case R_PPC64_GOT_TLSGD16_HA:
   case R_PPC64_GOT_TLSLD16_HA:
   case R_PPC64_GOT_TPREL16_HA:
   case R_PPC64_TOC16_HA:
     return {R_PPC64_ADDR16_HA, V};
+  case R_PPC64_DTPREL16_HI:
   case R_PPC64_GOT_TLSGD16_HI:
   case R_PPC64_GOT_TLSLD16_HI:
   case R_PPC64_GOT_TPREL16_HI:
   case R_PPC64_TOC16_HI:
     return {R_PPC64_ADDR16_HI, V};
+  case R_PPC64_DTPREL16_LO:
   case R_PPC64_GOT_TLSGD16_LO:
   case R_PPC64_GOT_TLSLD16_LO:
   case R_PPC64_TOC16_LO:


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