[llvm] bc63aba - Prevent out of range fixup encoding on AArch64

[Daniel Hoekwater via llvm-commits]

Author: Daniel Hoekwater
Date: 2023-06-16T15:29:59-07:00
New Revision: bc63abab97d8c59f60126a5e16316cae3a96f6b1

URL: https://github.com/llvm/llvm-project/commit/bc63abab97d8c59f60126a5e16316cae3a96f6b1
DIFF: https://github.com/llvm/llvm-project/commit/bc63abab97d8c59f60126a5e16316cae3a96f6b1.diff

LOG: Prevent out of range fixup encoding on AArch64

The range of a 21-bit signed integer is [-1048576, 1048575],
not [-2097152, 2097151].

Differential Revision: https://reviews.llvm.org/D152841

Added: 
    llvm/test/MC/AArch64/fixup-out-of-range-edge.s

Modified: 
    llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp

Removed: 
    


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diff  --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
index 7f20d73699829..a7933c00f5073 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
@@ -26,6 +26,7 @@
 #include "llvm/MC/MCValue.h"
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MathExtras.h"
 #include "llvm/TargetParser/Triple.h"
 using namespace llvm;
 
@@ -155,7 +156,7 @@ static uint64_t adjustFixupValue(const MCFixup &Fixup, const MCValue &Target,
   default:
     llvm_unreachable("Unknown fixup kind!");
   case AArch64::fixup_aarch64_pcrel_adr_imm21:
-    if (SignedValue > 2097151 || SignedValue < -2097152)
+    if (!isInt<21>(SignedValue))
       Ctx.reportError(Fixup.getLoc(), "fixup value out of range");
     return AdrImmBits(Value & 0x1fffffULL);
   case AArch64::fixup_aarch64_pcrel_adrp_imm21:
@@ -168,8 +169,8 @@ static uint64_t adjustFixupValue(const MCFixup &Fixup, const MCValue &Target,
     return AdrImmBits((Value & 0x1fffff000ULL) >> 12);
   case AArch64::fixup_aarch64_ldr_pcrel_imm19:
   case AArch64::fixup_aarch64_pcrel_branch19:
-    // Signed 21-bit immediate
-    if (SignedValue > 2097151 || SignedValue < -2097152)
+    // Signed 19-bit immediate which gets multiplied by 4
+    if (!isInt<21>(SignedValue))
       Ctx.reportError(Fixup.getLoc(), "fixup value out of range");
     if (Value & 0x3)
       Ctx.reportError(Fixup.getLoc(), "fixup not sufficiently aligned");

diff  --git a/llvm/test/MC/AArch64/fixup-out-of-range-edge.s b/llvm/test/MC/AArch64/fixup-out-of-range-edge.s
new file mode 100644
index 0000000000000..12de8e9889539
--- /dev/null
+++ b/llvm/test/MC/AArch64/fixup-out-of-range-edge.s
@@ -0,0 +1,53 @@
+// RUN: not llvm-mc -triple aarch64--none-eabi -filetype obj < %s -o /dev/null 2>&1 | FileCheck %s
+
+// COM: Edge case testing for branches and ADR[P]
+// CHECK-LABEL: :{{[0-9]+}}:{{[0-9]+}}: error: fixup value out of range
+// CHECK-NEXT:  adr x0, adr_lower
+adr_lower:
+  adr x0, adr_lower-(1<<20)-1
+
+// CHECK-LABEL: :{{[0-9]+}}:{{[0-9]+}}: error: fixup value out of range
+// CHECK-NEXT:  adr x0, adr_upper
+adr_upper:
+  adr x0, adr_upper+(1<<20)
+
+// CHECK-LABEL: :{{[0-9]+}}:{{[0-9]+}}: error: fixup value out of range
+// CHECK-NEXT: b b_lower
+b_lower:
+  b b_lower-(1<<27)-4
+
+// CHECK-LABEL: :{{[0-9]+}}:{{[0-9]+}}: error: fixup value out of range
+// CHECK-NEXT: b b_upper
+b_upper:
+  b b_upper+(1<<27)
+
+// CHECK-LABEL: :{{[0-9]+}}:{{[0-9]+}}: error: fixup value out of range
+// CHECK-NEXT: beq beq_lower
+beq_lower:
+  beq beq_lower-(1<<20)-4
+
+// CHECK-LABEL: :{{[0-9]+}}:{{[0-9]+}}: error: fixup value out of range
+// CHECK-NEXT: beq beq_upper
+beq_upper:
+  beq beq_upper+(1<<20)
+
+// CHECK-LABEL: :{{[0-9]+}}:{{[0-9]+}}: error: fixup value out of range
+// CHECK-NEXT: ldr x0, ldr_lower
+ldr_lower:
+  ldr x0, ldr_lower-(1<<20)-4
+
+// CHECK-LABEL: :{{[0-9]+}}:{{[0-9]+}}: error: fixup value out of range
+// CHECK-NEXT: ldr x0, ldr_upper
+ldr_upper:
+  ldr x0, ldr_upper+(1<<20)
+
+// CHECK-LABEL: :{{[0-9]+}}:{{[0-9]+}}: error: fixup value out of range
+// CHECK-NEXT: tbz x0, #1, tbz_lower
+tbz_lower:
+  tbz x0, #1, tbz_lower-(1<<15)-4
+
+// CHECK-LABEL: :{{[0-9]+}}:{{[0-9]+}}: error: fixup value out of range
+// CHECK-NEXT: tbz x0, #1, tbz_upper
+tbz_upper:
+  tbz x0, #1, tbz_upper+(1<<15)
+