Merge branch 'junghee/tls-local-exec' into 'main'

Fix bug that could result in missed symbolic expressions

Closes rewriting/transforms/gtirb-reachable#8

See merge request rewriting/ddisasm!1226

CHANGELOG.md

@@ -21,6 +21,7 @@
   sections
 * Fix 16-Thumb STM instructions considered to be invalid if the same register
   is used in reglist and register operands with writeback enabled.
+* Fixed bug that could result in missed symbolic expressions with TLS variables for `local-executable` TLS model
 
 # 1.9.0
 

examples/asm_examples/ex_tls_local_exec/Makefile

@@ -0,0 +1,9 @@
+
+all: ex_original.s
+	gcc -o ex ex_original.s
+	@./ex > out.txt
+clean:
+	rm -f ex out.txt
+check:
+	@./ex > /tmp/res.txt
+	@ diff out.txt /tmp/res.txt && echo TEST OK

examples/asm_examples/ex_tls_local_exec/ex_original.s

@@ -0,0 +1,63 @@
+
+.section .rodata
+    .align 8
+.LC:
+    .string "tls_var value: %d\n"
+
+.section .text ,"wa"
+
+    .align 16
+    .globl  get_tls_var
+    .type   get_tls_var, @function
+get_tls_var:
+    pushq   %rbp
+    movq    %rsp, %rbp
+var_tpoff_1:
+    movq    $var@tpoff, %rax
+    movq    %fs:0(%rax),%rax
+    popq    %rbp
+    ret
+
+    .size    get_tls_var, .-get_tls_var
+
+    .align 16
+    .globl  set_tls_var
+    .type   set_tls_var, @function
+set_tls_var:
+    pushq   %rbp
+    movq    %rsp, %rbp
+    movq    %rdi, -8(%rbp)
+var_tpoff_2:
+    movq    $var@tpoff, %rax
+    movq    -8(%rbp), %rdx
+    movq    %rdx, %fs:0(%rax)
+    nop
+    popq    %rbp
+    ret
+
+    .size    set_tls_var, .-set_tls_var
+
+    .align 16
+    .globl  main
+    .type   main, @function
+main:
+    pushq   %rbp
+    movq    %rsp, %rbp
+    movq    $7, %rdi
+    call    set_tls_var@PLT
+    movq    %rax, %rdi
+    call    get_tls_var@PLT
+    movq    %rax, %rsi
+    leaq    .LC(%rip), %rdi
+    call    printf@PLT
+    movl    $0, %eax
+    popq    %rbp
+    ret
+
+    .size    main, .-main
+
+.section .tbss ,"wa",@nobits
+
+    .align 8
+var:
+    .zero 8

src/datalog/binary/elf/tls.dl

@@ -525,6 +525,28 @@ tls_relative_operand(EA,Index,Dest,Type):-
     Base = as(@functor_aligned(TlsEnd, max(Align,1)),number),
     Dest = as(Base+Offset,address).
 
+// Local Executable (LE) TLS model,
+//   i.e. mov $var@tpoff, %rax
+//        mov %fs:0(%rax), %rdx
+tls_relative_operand(EA,Index,Dest,Type):-
+    tls_segment_register(Reg),
+    (
+        binary_isa("X64"),
+        Type = "TPOFF"
+        ;
+        binary_isa("X86"),
+        Type = "NTPOFF"
+    ),
+    const_value_reg_used(IndEA,EA,_,OffReg,Offset),
+    Offset < 0,
+    instruction_get_op(IndEA,_,Op),
+    op_indirect(Op,Reg,OffReg0,"NONE",_,0,_),
+    reg_map_nullable(OffReg0,OffReg),
+    arch.move_reg_imm(EA,OffReg,Offset,Index),
+    tls_segment(_,TlsEnd,Align),
+    Base = as(@functor_aligned(TlsEnd, max(Align,1)),number),
+    Dest = as(Base+Offset,address).
+
 // Local Executable (LE) TLS model,
 //   i.e. mov REG, FS:[0]
 //        lea REG, [REG + X@TPOFF]

tests/linux-elf-x64.yaml

@@ -512,6 +512,10 @@ tests:
     <<: *assembly
     binary: fun.so
 
+  - name: ex_tls_local_exec
+    <<: *assembly
+    binary: ex
+
   # ----------------------------------------------------------------------------
   # Assembly examples. (stripped)
   # ----------------------------------------------------------------------------
@@ -597,6 +601,11 @@ tests:
     <<: *test-strip-default
     binary: fun.so
 
+  - name: ex_tls_local_exec
+    <<: *assembly
+    <<: *test-strip-default
+    binary: ex
+
   # ----------------------------------------------------------------------------
   # Relocatable ELF objects (.o).
   # ----------------------------------------------------------------------------

tests/misc_test.py

@@ -14,6 +14,7 @@
 from pathlib import Path
 from typing import Optional, Tuple
 from gtirb.cfg import EdgeType
+from gtirb.symbolicexpression import SymbolicExpression
 import gtirb
 import lief
 
@@ -1016,5 +1017,43 @@ def test_zero_entry_point(self):
             self.assertEqual(len(list(m.symbols_named("_start"))), 0)
 
 
+class TLSLocalExecTests(unittest.TestCase):
+    @unittest.skipUnless(
+        platform.system() == "Linux", "This test is linux only."
+    )
+    def test_tls_local_exec(self):
+        """
+        Test that TLS attributes are correctly generated.
+        """
+
+        binary = Path("ex")
+        with cd(ex_asm_dir / "ex_tls_local_exec"):
+            self.assertTrue(compile("gcc", "g++", "-Os", []))
+            ir_library = disassemble(binary).ir()
+            m = ir_library.modules[0]
+
+            for sym_name in ["var_tpoff_1", "var_tpoff_2"]:
+                sym = next(m.symbols_named(sym_name))
+                self.assertIsInstance(sym.referent, gtirb.CodeBlock)
+
+                block = sym.referent
+                bi = block.byte_interval
+                # Get the sym-expr for the first instruction of size 7:
+                # movq var@tpoff, %rax
+                sexpr = set(
+                    bi.symbolic_expressions_at(
+                        range(block.address, block.address + 7)
+                    )
+                )
+                self.assertEqual(len(sexpr), 1)
+                se = next(iter(sexpr))[2]
+                self.assertIsInstance(se, gtirb.SymAddrConst)
+                self.assertEqual(se.symbol.name, "var")
+                self.assertEqual(se.offset, 0)
+                self.assertEqual(
+                    se.attributes, {SymbolicExpression.Attribute.TPOFF}
+                )
+
+
 if __name__ == "__main__":
     unittest.main()