[binutils-gdb] ubsan: epiphany: left shift of negative value

Alan Modra amodra@sourceware.org
Wed Dec 11 01:12:00 GMT 2019


https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b8e61daa1ad56330fd8931c8a53bfa16d8e4a47a

commit b8e61daa1ad56330fd8931c8a53bfa16d8e4a47a
Author: Alan Modra <amodra@gmail.com>
Date:   Tue Dec 10 18:06:09 2019 +1030

    ubsan: epiphany: left shift of negative value
    
    Two places in epiphany_cgen_extract_operand, "value" is a long.
            value = ((((value) << (1))) + (pc));
    
    cpu/
    	* epiphany.cpu (f-simm8, f-simm24): Use multiply rather than
    	shift left to avoid UB on left shift of negative values.
    opcodes/
    	* epiphany-ibld.c: Regenerate.

Diff:
---
 cpu/ChangeLog           | 5 +++++
 cpu/epiphany.cpu        | 4 ++--
 opcodes/ChangeLog       | 4 ++++
 opcodes/epiphany-ibld.c | 4 ++--
 4 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/cpu/ChangeLog b/cpu/ChangeLog
index 87cec69..fd26cb7 100644
--- a/cpu/ChangeLog
+++ b/cpu/ChangeLog
@@ -1,3 +1,8 @@
+2019-12-11  Alan Modra  <amodra@gmail.com>
+
+	* epiphany.cpu (f-simm8, f-simm24): Use multiply rather than
+	shift left to avoid UB on left shift of negative values.
+
 2019-11-20  Jose E. Marchesi  <jose.marchesi@oracle.com>
 
 	* bpf.cpu: Fix comment describing the 128-bit instruction format.
diff --git a/cpu/epiphany.cpu b/cpu/epiphany.cpu
index 33c81d0..9f873b3 100644
--- a/cpu/epiphany.cpu
+++ b/cpu/epiphany.cpu
@@ -149,11 +149,11 @@
 
 (df f-simm8	  "branch displacement"   (PCREL-ADDR RELOC) 15 8 INT
     ((value pc) (sra SI (sub SI value pc) 1))
-    ((value pc) (add SI (sll SI value 1) pc)))
+    ((value pc) (add SI (mul SI value 2) pc)))
 
 (df f-simm24     "branch displacement"	  (PCREL-ADDR RELOC) 31 24 INT
     ((value pc) (sra SI (sub SI value pc) 1))
-    ((value pc) (add SI (sll SI value 1) pc)))
+    ((value pc) (add SI (mul SI value 2) pc)))
 
 (df f-sdisp3     "signed immediate 3 bit"      ()     9 3  INT #f #f)
 
diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 4d22d51..de76acc 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,7 @@
+2019-12-11  Alan Modra  <amodra@gmail.com>
+
+	* epiphany-ibld.c: Regenerate.
+
 2019-12-10  Alan Modra  <amodra@gmail.com>
 
 	PR 24960
diff --git a/opcodes/epiphany-ibld.c b/opcodes/epiphany-ibld.c
index 83cfaf3..6e6fd7b 100644
--- a/opcodes/epiphany-ibld.c
+++ b/opcodes/epiphany-ibld.c
@@ -1100,7 +1100,7 @@ epiphany_cgen_extract_operand (CGEN_CPU_DESC cd,
       {
         long value;
         length = extract_normal (cd, ex_info, insn_value, 0|(1<<CGEN_IFLD_SIGNED)|(1<<CGEN_IFLD_RELOC)|(1<<CGEN_IFLD_PCREL_ADDR), 0, 31, 24, 32, total_length, pc, & value);
-        value = ((((value) << (1))) + (pc));
+        value = ((((value) * (2))) + (pc));
         fields->f_simm24 = value;
       }
       break;
@@ -1111,7 +1111,7 @@ epiphany_cgen_extract_operand (CGEN_CPU_DESC cd,
       {
         long value;
         length = extract_normal (cd, ex_info, insn_value, 0|(1<<CGEN_IFLD_SIGNED)|(1<<CGEN_IFLD_RELOC)|(1<<CGEN_IFLD_PCREL_ADDR), 0, 15, 8, 32, total_length, pc, & value);
-        value = ((((value) << (1))) + (pc));
+        value = ((((value) * (2))) + (pc));
         fields->f_simm8 = value;
       }
       break;



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