[BOLT] Add R_AARCH64_PREL16/32/64 relocations support

Alexey Moksyakov · yota9 · commit 48e894a53641 · 2022-04-21T13:52:47.000+03:00
Reviewed By: yota9, rafauler Differential Revision: https://reviews.llvm.org/D122294
diff --git a/bolt/include/bolt/Core/BinaryFunction.h b/bolt/include/bolt/Core/BinaryFunction.h
@@ -1279,6 +1279,9 @@ class BinaryFunction {
     case ELF::R_AARCH64_MOVW_UABS_G2:
     case ELF::R_AARCH64_MOVW_UABS_G2_NC:
     case ELF::R_AARCH64_MOVW_UABS_G3:
+    case ELF::R_AARCH64_PREL16:
+    case ELF::R_AARCH64_PREL32:
+    case ELF::R_AARCH64_PREL64:
       Rels[Offset] = Relocation{Offset, Symbol, RelType, Addend, Value};
       return;
     case ELF::R_AARCH64_CALL26:
diff --git a/bolt/lib/Core/Relocation.cpp b/bolt/lib/Core/Relocation.cpp
@@ -74,7 +74,9 @@ bool isSupportedAArch64(uint64_t Type) {
   case ELF::R_AARCH64_TLSDESC_ADD_LO12:
   case ELF::R_AARCH64_TLSDESC_CALL:
   case ELF::R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21:
+  case ELF::R_AARCH64_PREL16:
   case ELF::R_AARCH64_PREL32:
+  case ELF::R_AARCH64_PREL64:
   case ELF::R_AARCH64_ABS16:
   case ELF::R_AARCH64_ABS32:
   case ELF::R_AARCH64_ABS64:
@@ -121,6 +123,7 @@ size_t getSizeForTypeAArch64(uint64_t Type) {
     errs() << object::getELFRelocationTypeName(ELF::EM_AARCH64, Type) << '\n';
     llvm_unreachable("unsupported relocation type");
   case ELF::R_AARCH64_ABS16:
+  case ELF::R_AARCH64_PREL16:
     return 2;
   case ELF::R_AARCH64_CALL26:
   case ELF::R_AARCH64_JUMP26:
@@ -157,6 +160,7 @@ size_t getSizeForTypeAArch64(uint64_t Type) {
   case ELF::R_AARCH64_ABS32:
     return 4;
   case ELF::R_AARCH64_ABS64:
+  case ELF::R_AARCH64_PREL64:
     return 8;
   }
 }
@@ -258,7 +262,9 @@ uint64_t adjustValueAArch64(uint64_t Type, uint64_t Value, uint64_t PC) {
     llvm_unreachable("not supported relocation");
   case ELF::R_AARCH64_ABS32:
     break;
+  case ELF::R_AARCH64_PREL16:
   case ELF::R_AARCH64_PREL32:
+  case ELF::R_AARCH64_PREL64:
     Value -= PC;
     break;
   }
@@ -282,8 +288,12 @@ uint64_t extractValueAArch64(uint64_t Type, uint64_t Contents, uint64_t PC) {
   case ELF::R_AARCH64_ABS32:
   case ELF::R_AARCH64_ABS64:
     return Contents;
+  case ELF::R_AARCH64_PREL16:
+    return static_cast<int64_t>(PC) + SignExtend64<16>(Contents & 0xffff);
   case ELF::R_AARCH64_PREL32:
     return static_cast<int64_t>(PC) + SignExtend64<32>(Contents & 0xffffffff);
+  case ELF::R_AARCH64_PREL64:
+    return static_cast<int64_t>(PC) + Contents;
   case ELF::R_AARCH64_TLSDESC_CALL:
   case ELF::R_AARCH64_JUMP26:
   case ELF::R_AARCH64_CALL26:
@@ -505,7 +515,9 @@ bool isPCRelativeAArch64(uint64_t Type) {
   case ELF::R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21:
   case ELF::R_AARCH64_TLSDESC_ADR_PREL21:
   case ELF::R_AARCH64_TLSDESC_ADR_PAGE21:
+  case ELF::R_AARCH64_PREL16:
   case ELF::R_AARCH64_PREL32:
+  case ELF::R_AARCH64_PREL64:
     return true;
   }
 }
diff --git a/bolt/test/lit.cfg.py b/bolt/test/lit.cfg.py
@@ -90,6 +90,7 @@
     ToolSubst('llvm-readelf', unresolved='fatal'),
     ToolSubst('link_fdata', command=link_fdata_cmd, unresolved='fatal'),
     ToolSubst('merge-fdata', unresolved='fatal'),
+    ToolSubst('llvm-readobj', unresolved='fatal'),
 ]
 llvm_config.add_tool_substitutions(tools, tool_dirs)
 
diff --git a/bolt/test/runtime/AArch64/r_aarch64_prelxx.s b/bolt/test/runtime/AArch64/r_aarch64_prelxx.s
@@ -0,0 +1,37 @@
+// This test checks processing of R_AARCH64_PREL64/32/16 relocations
+
+// RUN: %clang %cflags -nostartfiles -nostdlib %s -o %t.exe -Wl,-q \
+// RUN:     -Wl,-z,max-page-size=4
+// RUN: llvm-readelf -Wa %t.exe | FileCheck %s -check-prefix=CHECKPREL
+
+// CHECKPREL:       R_AARCH64_PREL16      {{.*}} .dummy + 0
+// CHECKPREL-NEXT:  R_AARCH64_PREL32      {{.*}} _start + 4
+// CHECKPREL-NEXT:  R_AARCH64_PREL64      {{.*}} _start + 8
+
+// RUN: llvm-bolt %t.exe -o %t.bolt
+// RUN: llvm-readobj -S --section-data %t.bolt | FileCheck %s
+
+// CHECK: Name: .data
+// CHECK: SectionData (
+// CHECK:   0000: FCFF0000 44FF3F00 44FF3F00 00000000
+// CHECK: )
+
+  .text
+  .align 4
+  .globl _start
+  .type _start, %function
+_start:
+  adr x0, datatable
+  mov x0, #0
+  ret 
+
+.section .dummy, "da"
+dummy:
+  .word 0
+
+.section .data
+datatable:
+  .hword dummy - datatable
+  .align 2
+  .word _start - datatable
+  .xword _start - datatable
diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
@@ -446,6 +446,13 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
     write(isBE, TargetPtr, static_cast<uint32_t>(Result));
     break;
   }
+  case ELF::R_AARCH64_PREL16: {
+    uint64_t Result = Value + Addend - FinalAddress;
+    assert(static_cast<int64_t>(Result) >= INT16_MIN &&
+           static_cast<int64_t>(Result) <= UINT16_MAX);
+    write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU));
+    break;
+  }
   case ELF::R_AARCH64_PREL32: {
     uint64_t Result = Value + Addend - FinalAddress;
     assert(static_cast<int64_t>(Result) >= INT32_MIN &&
diff --git a/llvm/lib/Object/RelocationResolver.cpp b/llvm/lib/Object/RelocationResolver.cpp
@@ -78,6 +78,7 @@ static bool supportsAArch64(uint64_t Type) {
   switch (Type) {
   case ELF::R_AARCH64_ABS32:
   case ELF::R_AARCH64_ABS64:
+  case ELF::R_AARCH64_PREL16:
   case ELF::R_AARCH64_PREL32:
   case ELF::R_AARCH64_PREL64:
     return true;
@@ -93,6 +94,8 @@ static uint64_t resolveAArch64(uint64_t Type, uint64_t Offset, uint64_t S,
     return (S + Addend) & 0xFFFFFFFF;
   case ELF::R_AARCH64_ABS64:
     return S + Addend;
+  case ELF::R_AARCH64_PREL16:
+    return (S + Addend - Offset) & 0xFFFF;
   case ELF::R_AARCH64_PREL32:
     return (S + Addend - Offset) & 0xFFFFFFFF;
   case ELF::R_AARCH64_PREL64:

Original file line number	Diff line number	Diff line change
`@@ -90,6 +90,7 @@`
`90`	`90`	`ToolSubst('llvm-readelf', unresolved='fatal'),`
`91`	`91`	`ToolSubst('link_fdata', command=link_fdata_cmd, unresolved='fatal'),`
`92`	`92`	`ToolSubst('merge-fdata', unresolved='fatal'),`
	`93`	`+ ToolSubst('llvm-readobj', unresolved='fatal'),`
`93`	`94`	`]`
`94`	`95`	`llvm_config.add_tool_substitutions(tools, tool_dirs)`
`95`	`96`