[Webkit-unassigned] [Bug 202844] New: Invalid instruction generated for ARM_THUMB2 in llint

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=202844

            Bug ID: 202844
           Summary: Invalid instruction generated for ARM_THUMB2 in llint
           Product: WebKit
           Version: WebKit Nightly Build
          Hardware: Unspecified
                OS: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: JavaScriptCore
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: pmatos at igalia.com

Post bug 197993 (r250806), JSC 32bit started failing with many segmentation faults.

Debugging the segfault we see that we are hitting addresses that shouldn't be reachable. 
    0x2582ee <llint_op_call+314>    blx    r0
  >│0x2582f0 <llint_op_call+316>    eorseq lr, r4, r8, lsr sp
    0x2582f4 <llint_op_call+320>    andeq  r2, r0, r8, rrx
    0x2582f8 <llint_op_call+324>    ldr    r2, [r7, #8]

LLIntAssembly.h looks like:
  OFFLINE_ASM_LOCAL_LABEL(_offlineasm_callOp__commonCallOp__llintOpWithMetadata__llintOpWithRe
turn__llintOp__commonOp__fn__fn__makeReturn__fn__fn__fn__slowPathForCall__callCallSlowPath__51
1_action__dontUpdateSP)
    "\tmovw r10, #55459\n"                                   // /home/pmatos/dev/igalia/WebKit
/Source/JavaScriptCore/llint/LowLevelInterpreter.asm:256
    "\tblx r0\n"                                             // /home/pmatos/dev/igalia/WebKit/Source/JavaScriptCore/llint/LowLevelInterpreter.asm:952
    "\t" LOCAL_LABEL_STRING(offlineasm_arm_got_1020) ":\n"
    "\t.word _GLOBAL_OFFSET_TABLE_-(" LOCAL_LABEL_STRING(offlineasm_arm_got_offset_1020) "+4)\n"
    "\t.word " LOCAL_REFERENCE(g_opcodeMap) "(GOT)\n"

OFFLINE_ASM_GLUE_LABEL(op_construct_slow_return_location_wide32)
    "\tldr r2, [r7, #8]\n"

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