[BOLT] Fix long jump negative offset issue.

bolt/lib/Passes/LongJmp.cpp

@@ -138,18 +138,21 @@ BinaryBasicBlock *LongJmpPass::lookupStubFromGroup(
       Cand = LeftCand;
   }
   int BitsAvail = BC.MIB->getPCRelEncodingSize(Inst) - 1;
-  uint64_t Mask = ~((1ULL << BitsAvail) - 1);
+  assert(BitsAvail < 63 && "PCRelEncodingSize is too large to use int64_t to"
+                           "check for out-of-bounds.");
+  int64_t MaxVal = (1ULL << BitsAvail) - 1;
+  int64_t MinVal = -(1ULL << BitsAvail);
   uint64_t PCRelTgtAddress = Cand->first;
-  PCRelTgtAddress = DotAddress > PCRelTgtAddress ? DotAddress - PCRelTgtAddress
-                                                 : PCRelTgtAddress - DotAddress;
+  int64_t PCOffset = (int64_t)(PCRelTgtAddress - DotAddress);
+
   LLVM_DEBUG({
     if (Candidates.size() > 1)
       dbgs() << "Considering stub group with " << Candidates.size()
              << " candidates. DotAddress is " << Twine::utohexstr(DotAddress)
              << ", chosen candidate address is "
              << Twine::utohexstr(Cand->first) << "\n";
   });
-  return PCRelTgtAddress & Mask ? nullptr : Cand->second;
+  return (PCOffset < MinVal || PCOffset > MaxVal) ? nullptr : Cand->second;
 }
 
 BinaryBasicBlock *
@@ -512,13 +515,15 @@ bool LongJmpPass::needsStub(const BinaryBasicBlock &BB, const MCInst &Inst,
   }
 
   int BitsAvail = BC.MIB->getPCRelEncodingSize(Inst) - 1;
-  uint64_t Mask = ~((1ULL << BitsAvail) - 1);
+  assert(BitsAvail < 63 && "PCRelEncodingSize is too large to use int64_t to"
+                           "check for out-of-bounds.");
+  int64_t MaxVal = (1ULL << BitsAvail) - 1;
+  int64_t MinVal = -(1ULL << BitsAvail);
 
   uint64_t PCRelTgtAddress = getSymbolAddress(BC, TgtSym, TgtBB);
-  PCRelTgtAddress = DotAddress > PCRelTgtAddress ? DotAddress - PCRelTgtAddress
-                                                 : PCRelTgtAddress - DotAddress;
+  int64_t PCOffset = (int64_t)(PCRelTgtAddress - DotAddress);
 
-  return PCRelTgtAddress & Mask;
+  return PCOffset < MinVal || PCOffset > MaxVal;
 }
 
 bool LongJmpPass::relax(BinaryFunction &Func) {

bolt/test/AArch64/Inputs/long-jmp-offset-boundary.ld

@@ -0,0 +1,11 @@
+SECTIONS {
+    . = 0;
+    . = ALIGN(0x400000);
+    .text : {
+        *(foo_section)
+        . += 0x7BFFFFC;
+        *(main_section)
+        ASSERT(foo == 0x400000, "Error: foo address is not 0x400000.");
+        ASSERT(_start == 0x8000000, "Error: _start address is not 0x8000000.");
+    }
+}

bolt/test/AArch64/long-jmp-offset-boundary.s

@@ -0,0 +1,31 @@
+# This test checks long call negative offset boundary(0x8000000) for aarch64.
+
+# REQUIRES: system-linux
+
+# RUN: llvm-mc -filetype=obj -triple aarch64-unknown-unknown \
+# RUN:   %s -o %t.o
+# RUN: %clang %cflags %t.o -o %t.exe -nostartfiles -fuse-ld=lld -Wl,-q \
+# RUN:   -Wl,--script=%p/Inputs/long-jmp-offset-boundary.ld
+# RUN: llvm-bolt %t.exe -o %t.bolt.exe -skip-funcs="foo.*"
+# RUN: llvm-objdump -d -j .text --print-imm-hex %t.bolt.exe | FileCheck %s
+
+# The default alignment of the new program header table and the new text is
+# HugePageSize(2MB).
+# CHECK: [[#%x,ADDR:]]: [[#]]     	bl
+# CHECK-SAME: 	0x[[#ADDR-0x8000000]] <foo>
+
+	.text
+	.section	foo_section,"ax",@progbits
+	.globl	foo
+	.type	foo,@function
+foo:
+	ret
+	.size	foo, .-foo
+
+	.section	main_section,"ax",@progbits
+	.globl	_start
+	.type	_start,@function
+_start:
+	bl	foo
+	ret
+	.size	_start, .-_start