[COFF, ARM64] Don't put jump table into a separate COFF section for EK_LabelDifference32

Windows ARM64 has PIC relocation model and uses jump table kind
EK_LabelDifference32. This produces jump table entry as
".word LBB123 - LJTI1_2" which represents the distance between the block
and jump table.

A new relocation type (IMAGE_REL_ARM64_REL32) is needed to do the fixup
correctly if they are in different COFF section.

This change saves the jump table to the same COFF section as the
associated code. An ideal fix could be utilizing IMAGE_REL_ARM64_REL32
relocation type.

Patch by Tom Tan!

Differential Revision: https://reviews.llvm.org/D57277

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@352465 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AArch64/AArch64AsmPrinter.cpp b/lib/Target/AArch64/AArch64AsmPrinter.cpp
index 3b172a8..61196ba 100644 (file)
--- a/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -578,9 +578,18 @@ void AArch64AsmPrinter::EmitJumpTableInfo() {
   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
   if (JT.empty()) return;
 
+  const Function &F = MF->getFunction();
   const TargetLoweringObjectFile &TLOF = getObjFileLowering();
-  MCSection *ReadOnlySec = TLOF.getSectionForJumpTable(MF->getFunction(), TM);
-  OutStreamer->SwitchSection(ReadOnlySec);
+  bool JTInDiffSection =
+      !STI->isTargetCOFF() ||
+      !TLOF.shouldPutJumpTableInFunctionSection(
+          MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
+          F);
+  if (JTInDiffSection) {
+      // Drop it in the readonly section.
+      MCSection *ReadOnlySec = TLOF.getSectionForJumpTable(F, TM);
+      OutStreamer->SwitchSection(ReadOnlySec);
+  }
 
   auto AFI = MF->getInfo<AArch64FunctionInfo>();
   for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {

diff --git a/lib/Target/AArch64/AArch64TargetMachine.cpp b/lib/Target/AArch64/AArch64TargetMachine.cpp
index c9a2b80..d213f20 100644 (file)
--- a/lib/Target/AArch64/AArch64TargetMachine.cpp
+++ b/lib/Target/AArch64/AArch64TargetMachine.cpp
@@ -208,8 +208,8 @@ static std::string computeDataLayout(const Triple &TT,
 
 static Reloc::Model getEffectiveRelocModel(const Triple &TT,
                                            Optional<Reloc::Model> RM) {
-  // AArch64 Darwin is always PIC.
-  if (TT.isOSDarwin())
+  // AArch64 Darwin and Windows are always PIC.
+  if (TT.isOSDarwin() || TT.isOSWindows())
     return Reloc::PIC_;
   // On ELF platforms the default static relocation model has a smart enough
   // linker to cope with referencing external symbols defined in a shared

diff --git a/test/CodeGen/AArch64/win64-jumptable.ll b/test/CodeGen/AArch64/win64-jumptable.ll
new file mode 100644 (file)
index 0000000..8148a59
--- /dev/null
+++ b/test/CodeGen/AArch64/win64-jumptable.ll
@@ -0,0 +1,48 @@
+; RUN: llc -o - %s -mtriple=aarch64-windows -aarch64-enable-compress-jump-tables=0 | FileCheck %s
+
+define void @f(i32 %x) {
+entry:
+  switch i32 %x, label %sw.epilog [
+    i32 0, label %sw.bb
+    i32 1, label %sw.bb1
+    i32 2, label %sw.bb2
+    i32 3, label %sw.bb3
+  ]
+
+sw.bb:                                            ; preds = %entry
+  tail call void @g(i32 0) #2
+  br label %sw.epilog
+
+sw.bb1:                                           ; preds = %entry
+  tail call void @g(i32 1) #2
+  br label %sw.epilog
+
+sw.bb2:                                           ; preds = %entry
+  tail call void @g(i32 2) #2
+  br label %sw.epilog
+
+sw.bb3:                                           ; preds = %entry
+  tail call void @g(i32 3) #2
+  br label %sw.epilog
+
+sw.epilog:                                        ; preds = %entry, %sw.bb3, %sw.bb2, %sw.bb1, %sw.bb
+  tail call void @g(i32 10) #2
+  ret void
+}
+
+declare void @g(i32)
+
+; CHECK:               .text
+; CHECK:               f:
+; CHECK:               .seh_proc f
+; CHECK:               b       g
+; CHECK-NEXT:  .p2align        2
+; CHECK-NEXT:  .LJTI0_0:
+; CHECK:               .word   .LBB0_2-.LJTI0_0
+; CHECK:               .word   .LBB0_3-.LJTI0_0
+; CHECK:               .word   .LBB0_4-.LJTI0_0
+; CHECK:               .word   .LBB0_5-.LJTI0_0
+; CHECK:               .section        .xdata,"dr"
+; CHECK:               .seh_handlerdata
+; CHECK:               .text
+; CHECK:               .seh_endproc