[llvm-mc] - Produce R_X86_64_PLT32 relocation for branches with JCC o…

…pcodes too.

The idea is to produce R_X86_64_PLT32 instead of
R_X86_64_PC32 for branches.

It fixes https://bugs.llvm.org/show_bug.cgi?id=44397.

This patch teaches MC to do that for JCC (jump if condition is met)
instructions. The new behavior matches modern GNU as.
It is similar to D43383, which did the same for "call/jmp foo",
but missed JCC cases.

Differential revision: https://reviews.llvm.org/D72831

llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp

@@ -275,7 +275,8 @@ static bool hasSecRelSymbolRef(const MCExpr *Expr) {
 static bool isPCRel32Branch(const MCInst &MI, const MCInstrInfo &MCII) {
   unsigned Opcode = MI.getOpcode();
   const MCInstrDesc &Desc = MCII.get(Opcode);
-  if ((Opcode != X86::CALL64pcrel32 && Opcode != X86::JMP_4) ||
+  if ((Opcode != X86::CALL64pcrel32 && Opcode != X86::JMP_4 &&
+       Opcode != X86::JCC_4) ||
       getImmFixupKind(Desc.TSFlags) != FK_PCRel_4)
     return false;
 

llvm/test/MC/ELF/basic-elf-64.s

@@ -14,6 +14,37 @@ main:                                   # @main
 	xorl	%eax, %eax
 	addq	$8, %rsp
     call foo@GOTPCREL
+    ja foo
+    jae foo
+    jb foo
+    jbe foo
+    jc foo
+    je foo
+    jz foo
+    jg foo
+    jge foo
+    jl foo
+    jle foo
+    jna foo
+    jnae foo
+    jnb foo
+    jnbe foo
+    jnc foo
+    jne foo
+    jng foo
+    jnge foo
+    jnl foo
+    jnle foo
+    jno foo
+    jnp foo
+    jns foo
+    jnz foo
+    jo foo
+    jp foo
+    jpe foo
+    jpo foo
+    js foo
+    jz foo
 	ret
 .Ltmp0:
 	.size	main, .Ltmp0-main
@@ -52,6 +83,37 @@ main:                                   # @main
 // CHECK-NEXT:     0xF  R_X86_64_32   .rodata.str1.1 0x6
 // CHECK-NEXT:     0x14 R_X86_64_PLT32 puts           0xFFFFFFFFFFFFFFFC
 // CHECK-NEXT:     0x1F R_X86_64_GOTPCREL foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x25 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x2B R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x31 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x37 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x3D R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x43 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x49 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x4F R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x55 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x5B R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x61 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x67 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x6D R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x73 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x79 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x7F R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x85 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x8B R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x91 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x97 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0x9D R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0xA3 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0xA9 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0xAF R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0xB5 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0xBB R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0xC1 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0xC7 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0xCD R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0xD3 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT:     0xD9 R_X86_64_PLT32 foo 0xFFFFFFFFFFFFFFFC
 // CHECK-NEXT:   }
 // CHECK-NEXT: ]