Re: [patch 3/3] Displaced stepping for 16-bit Thumb instructions

[Yao Qi <yao@codesourcery.com>]

[-- Attachment #1: Type: text/plain, Size: 618 bytes --]

On 12/25/2010 10:21 PM, Yao Qi wrote:
> gdb/testsuite/
> 2010-12-25  Yao Qi  <yao@codesourcery.com>
> 
> 	* gdb.arch/arm-disp-step.S: Test cbnz/cbz, adr and ldr.
> 	* gdb.arch/arm-disp-step.exp: Likewise.

In my previous patch, displaced stepping is turned off in test_call_ret,
but 'forget' to turn it on again.  This patch is to address this problem
by replacing original gdb_continue_to_breakpoint by
try_continue_with_displaced_step, in which displaced stepping is turned
on, and make sure GDB can do displaced stepping on that instruction, so
displaced stepping can't be turned off again.

-- 
Yao (齐尧)

[-- Attachment #2: arm_disp_step_thumb_16bit_test_1227.patch --]
[-- Type: text/x-patch, Size: 9180 bytes --]

diff --git a/gdb/testsuite/gdb.arch/arm-disp-step.S b/gdb/testsuite/gdb.arch/arm-disp-step.S
index d748718..2e5b7ba 100644
--- a/gdb/testsuite/gdb.arch/arm-disp-step.S
+++ b/gdb/testsuite/gdb.arch/arm-disp-step.S
@@ -48,6 +48,26 @@ test_ret_end:
 	bl test_ldm_stm_pc
 #endif
 
+	/* Test ldrX literal in ARM and Thumb-2 */
+#if !defined (__thumb__)
+	bl test_ldr_literal
+#endif
+
+	/* Test ldr literal in Thumb */
+#if defined(__thumb__)
+	bl test_ldr_literal_16
+#endif
+
+	/* Test cbnz/cbz in Thumb-2 */
+#if defined(__thumb2__)
+	bl test_cbz_cbnz
+#endif
+
+	/* Test adr in Thumb and Thumb-2 */
+#if defined(__thumb) || defined(__thumb2__)
+	bl test_adr
+#endif
+	
 	/* Return */
 	mov     sp, r7
 	sub     sp, sp, #4
@@ -118,3 +138,75 @@ test_ldm_stm_pc_ret:
 	.word	test_ldm_stm_pc_ret
 	.size test_ldm_stm_pc, .-test_ldm_stm_pc
 #endif
+	
+#if !defined (__thumb__)
+	.global test_ldr_literal
+	.type test_ldr_literal, %function
+test_ldr_literal:
+	ldrh	r0, [pc]
+	.global test_ldrsb_literal
+test_ldrsb_literal:
+	ldrsb	r0, [pc]
+	.global test_ldrsh_literal
+test_ldrsh_literal:
+	ldrsh	r0, [pc]
+	.global test_ldr_literal_end
+test_ldr_literal_end:
+	bx lr
+	.size test_ldr_literal, .-test_ldr_literal
+#endif
+
+#if defined(__thumb__)
+	.global test_ldr_literal_16
+	.code   16
+	.thumb_func
+test_ldr_literal_16:
+	ldr	r0, .L2
+	.global test_ldr_literal_16_end
+test_ldr_literal_16_end:
+	bx lr
+	.align	2
+.L2:
+	.word	test_ldr_literal_16
+	.size test_ldr_literal_16, .-test_ldr_literal_16
+#endif
+
+#if defined(__thumb2__)
+	.global test_cbz_cbnz
+	.code   16
+	.thumb_func
+test_cbz_cbnz:
+	movs 	r0, #0
+	.global test_zero_cbnz
+test_zero_cbnz:
+	cbnz	r0, .L3
+	.global test_zero_cbz
+test_zero_cbz:
+	cbz	r0, .L3
+.L3:
+	movs	r0, #1
+	.global test_non_zero_cbz
+test_non_zero_cbz:
+	cbz	r0, .L4
+	.global test_non_zero_cbnz
+test_non_zero_cbnz:
+	cbnz	r0, .L4
+	nop
+.L4:
+	.global test_cbz_cbnz_end
+test_cbz_cbnz_end:
+	bx lr
+	.size test_cbz_cbnz, .-test_cbz_cbnz
+#endif
+
+#if defined(__thumb) || defined(__thumb2__)
+	.global test_adr
+	.code   16
+	.thumb_func
+test_adr:
+	adr	r0, #1
+	.global test_adr_end
+test_adr_end:
+	bx lr
+	.size test_adr, .-test_adr
+#endif
\ No newline at end of file
diff --git a/gdb/testsuite/gdb.arch/arm-disp-step.exp b/gdb/testsuite/gdb.arch/arm-disp-step.exp
index 826f728..a8d2adc 100644
--- a/gdb/testsuite/gdb.arch/arm-disp-step.exp
+++ b/gdb/testsuite/gdb.arch/arm-disp-step.exp
@@ -37,6 +37,22 @@ if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable [list
     return -1
 }
 
+# Try to resume program with displaced stepping.  If displaced stepping is
+# not supported, turn it off, and continue.
+
+proc try_continue_with_displaced_step { msg loc } {
+    gdb_test_no_output "set displaced-stepping on"
+    gdb_test_multiple "continue" "continue to $msg" {
+	-re ".*$loc.*" {
+	    pass "continue to $msg"
+	}
+	-re "Displaced stepping is only supported in.*" {
+	    gdb_test_no_output "set displaced-stepping off"
+	    gdb_test "continue" ".*"
+	    kfail "gdb/NNNN" $msg
+	}
+    }
+}
 
 #########################################
 # Test ldm/stm related to PC.
@@ -50,7 +66,11 @@ proc test_ldm_stm_pc {} {
 	}
 	-re "Function \"test_ldm_stm_pc\" not defined\..*Make breakpoint pending on future shared library load.*y or .n.. $" {
 	    gdb_test "n" "" "Test case is compiled in Thumb mode"
-	    return
+	    return 0
+	}
+	-re "No symbol.*" {
+	    pass "break test_ldm_stm_pc"
+	    return 0
 	}
     }
 
@@ -68,10 +88,75 @@ proc test_ldm_stm_pc {} {
     gdb_continue_to_breakpoint "continue to test_ldm_stm_pc_ret" \
 	".*bx lr.*"
 }
+
+#########################################
+# Test ldrX literal
+proc test_ldr_literal {} {
+    global srcfile
+    # Try to set breakpoint on test_ldm_stm_pc.  If symbol 'test_ldm_stm_pc'
+    # can't be resolved, test case is compiled in Thumb mode, skip it.
+    gdb_test_multiple "break *test_ldr_literal" "break test_ldr_literal" {
+	-re "Breakpoint.*at.* file .*$srcfile, line.*" {
+	    pass "break test_ldr_literal"
+	}
+	-re "Function \"test_ldr_literal\" not defined\..*Make breakpoint pending on future shared library load.*y or .n.. $" {
+	    gdb_test "n" "" "Test case is compiled in Thumb mode"
+	    return 0
+	}
+	-re "No symbol.*" {
+	    return 0
+	}
+    }
+
+    gdb_test "break *test_ldrsb_literal" \
+	"Breakpoint.*at.* file .*$srcfile, line.*" \
+	"break test_ldrsb_literal"
+    gdb_test "break *test_ldrsh_literal" \
+	"Breakpoint.*at.* file .*$srcfile, line.*" \
+	"break test_ldrsh_literal"
+    gdb_test "break *test_ldr_literal_end" \
+	"Breakpoint.*at.* file .*$srcfile, line.*" \
+	"break test_test_ldr_literal_end"
+
+    gdb_continue_to_breakpoint "continue to test_ldr_literal" \
+	".*ldrh.*r0\,.*\[pc\].*"
+    gdb_continue_to_breakpoint "continue to test_ldrsb_literal" \
+	".*ldrsb.*r0\,.*\[pc\].*"
+    gdb_continue_to_breakpoint "continue to test_ldrsh_literal" \
+	".*ldrsh.*r0\,.*\[pc\].*"
+    gdb_continue_to_breakpoint "continue to test_ldr_literal_ret" \
+	".*bx lr.*"
+
+    gdb_test_multiple "break test_ldr_literal_16" "break test_ldr_literal_16" {
+	-re "Breakpoint.*at.* file .*$srcfile, line.*" {
+	    pass "break test_ldr_literal"
+	}
+	-re "Function \"test_ldr_literal_16\" not defined\..*Make breakpoint pending on future shared library load.*y or .n.. $" {
+	    gdb_test "n" "" "skip"
+	    return 0
+	}
+    }
+    
+    gdb_test "break *test_ldr_literal_16_end" \
+	"Breakpoint.*at.* file .*$srcfile, line.*" \
+	"break test_test_ldr_literal_16_end"
+
+    gdb_continue_to_breakpoint "continue to test_ldr_literal" \
+	".*ldr.*r0\,.*L2.*"
+    gdb_continue_to_breakpoint "continue to test_ldrsb_literal" \
+	".*bx lr.*"
+}
+
 ##########################################
 # Test call/ret.
 proc test_call_ret {} {
     global srcfile
+    global testfile
+
+    gdb_test "break *test_call" \
+	"Breakpoint.*at.* file .*$srcfile, line.*" \
+	"break test_call"
+
     gdb_test "break *test_call_end" \
 	"Breakpoint.*at.* file .*$srcfile, line.*" \
 	"break test_call_end"
@@ -82,10 +167,12 @@ proc test_call_ret {} {
 	"Breakpoint.*at.* file .*$srcfile, line.*" \
 	"break test_ret_end"
 
-    gdb_continue_to_breakpoint "continue to test_call_end" \
-	".*@ Location test_call_end.*"
-    gdb_continue_to_breakpoint "continue to test_ret" \
+    try_continue_with_displaced_step "test_call" "bl test_call_subr"
+    try_continue_with_displaced_step "test_call_end" \
+	"@ Location test_call_end"
+    try_continue_with_displaced_step "test_ret" \
 	".*bx lr.*"
+
     gdb_continue_to_breakpoint "continue to test_ret_end" \
 	".*@ Location test_ret_end.*"
 }
@@ -122,7 +209,66 @@ proc test_ldr_from_pc {} {
 
     gdb_continue_to_breakpoint "continue to test_ldr_pc" \
 	".*ldr.*r1\,.*\[pc, #0\].*"
-    gdb_continue_to_breakpoint "continue to Lbranch" \
+    gdb_continue_to_breakpoint "continue to test_ldr_pc_ret" \
+	".*bx lr.*"
+}
+
+#########################################
+
+# Test cbz and cbnz
+proc test_cbz_cbnz {} {
+    global srcfile
+
+    gdb_test_multiple "break *test_zero_cbnz" "break test_zero_cbnz" {
+	-re "Breakpoint.*at.* file .*$srcfile, line.*" {
+	    pass "break test_ldr_literal"
+	}
+	-re "No symbol.*" {
+	    return 0
+	}
+    }
+
+    gdb_test "break *test_zero_cbz" \
+	"Breakpoint.*at.* file .*$srcfile, line.*" \
+	"break test_zero_cbz"
+    gdb_test "break *test_non_zero_cbnz" \
+	"Breakpoint.*at.* file .*$srcfile, line.*" \
+	"break test_non_zero_cbnz"
+    gdb_test "break *test_non_zero_cbz" \
+	"Breakpoint.*at.* file .*$srcfile, line.*" \
+	"break test_non_zero_cbz"
+
+    gdb_continue_to_breakpoint "continue to test_zero_cbnz" \
+	".*cbnz.*r0\,.*\.L3.*"
+    gdb_continue_to_breakpoint "continue to test_zero_cbz" \
+	".*cbz.*r0\,.*\.L3.*"
+    gdb_continue_to_breakpoint "continue to test_non_zero_cbz" \
+	".*cbz.*r0\,.*\.L4.*"
+    gdb_continue_to_breakpoint "continue to test_non_zero_cbnz" \
+	".*cbnz.*r0\,.*\.L4.*"
+}
+
+# Test adr
+
+proc test_adr {} {
+    global srcfile
+
+    gdb_test_multiple "break *test_adr" "break test_adr" {
+	-re "Breakpoint.*at.* file .*$srcfile, line.*" {
+	    pass "break test_adr"
+	}
+	-re "No symbol.*" {
+	    return 0
+	}
+    }
+
+    gdb_test "break *test_adr_end" \
+	"Breakpoint.*at.* file .*$srcfile, line.*" \
+	"break test_adr_end"
+
+    try_continue_with_displaced_step "test_adr" \
+	"adr.*r0\,.*#1"
+    try_continue_with_displaced_step "test_adr_end" \
 	".*bx lr.*"
 }
 
@@ -143,20 +289,6 @@ if ![runto_main] then {
 gdb_test_no_output "set displaced-stepping on"
 gdb_test "show displaced-stepping" ".* displaced stepping .* is on.*"
 
-gdb_test "break *test_call" \
-	"Breakpoint.*at.* file .*$srcfile, line.*" \
-	"break test_call"
-
-gdb_test_multiple "continue" "continue to test_call" {
-	-re ".*bl test_call_subr.*" {
-	    pass "continue to test_call"
-	}
-	-re "Displaced stepping is only supported in" {
-	    kfail "gdb/NNNN" $testfile
-	    return
-	}
-    }
-
 test_call_ret
 
 test_branch
@@ -165,6 +297,11 @@ test_ldr_from_pc
 
 test_ldm_stm_pc
 
+test_ldr_literal
+
+test_cbz_cbnz
+
+test_adr
 ##########################################
 
 # Done, run program to exit.