* src/vm/jit/powerpc64/emit.c (emit_branch): Added a displacement

check for conditional long-branches.

diff --git a/src/vm/jit/powerpc64/emit.c b/src/vm/jit/powerpc64/emit.c
index bb14ba1af5217d7456339dc23fb60f3d43b4c1e4..4e7a37f718c21b0200688098c29e828f78dc7257 100644 (file)
--- a/src/vm/jit/powerpc64/emit.c
+++ b/src/vm/jit/powerpc64/emit.c
@@ -429,39 +429,47 @@ void emit_branch(codegendata *cd, s4 disp, s4 condition, s4 reg, u4 opt)
                                                          CODEGENDATA_FLAG_LONGBRANCHES);
                        }
 
-                       branchdisp --;          /* we jump from the second instruction */
-                       switch (condition) {
-                       case BRANCH_EQ:
-                               M_BNE(1);
-                               M_BR(branchdisp);
-                               break;
-                       case BRANCH_NE:
-                               M_BEQ(1);
-                               M_BR(branchdisp);
-                               break;
-                       case BRANCH_LT:
-                               M_BGE(1);
-                               M_BR(branchdisp);
-                               break;
-                       case BRANCH_GE:
-                               M_BLT(1);
-                               M_BR(branchdisp);
-                               break;
-                       case BRANCH_GT:
-                               M_BLE(1);
-                               M_BR(branchdisp);
-                               break;
-                       case BRANCH_LE:
-                               M_BGT(1);
-                               M_BR(branchdisp);
-                               break;
-                       case BRANCH_NAN:
-                               vm_abort("emit_branch: long BRANCH_NAN");
-                               break;
-                       default:
-                               vm_abort("emit_branch: unknown condition %d", condition);
-                       }
+                       // Subtract 1 instruction from the displacement as the
+                       // actual branch is the second instruction.
+                       checkdisp  = checkdisp - 4;
+                       branchdisp = branchdisp - 1;
 
+                       if ((checkdisp < (int32_t) 0xfe000000) || (checkdisp > (int32_t) 0x01fffffc)) {
+                               vm_abort("emit_branch: emit conditional long-branch code");
+                       }
+                       else {
+                               switch (condition) {
+                               case BRANCH_EQ:
+                                       M_BNE(1);
+                                       M_BR(branchdisp);
+                                       break;
+                               case BRANCH_NE:
+                                       M_BEQ(1);
+                                       M_BR(branchdisp);
+                                       break;
+                               case BRANCH_LT:
+                                       M_BGE(1);
+                                       M_BR(branchdisp);
+                                       break;
+                               case BRANCH_GE:
+                                       M_BLT(1);
+                                       M_BR(branchdisp);
+                                       break;
+                               case BRANCH_GT:
+                                       M_BLE(1);
+                                       M_BR(branchdisp);
+                                       break;
+                               case BRANCH_LE:
+                                       M_BGT(1);
+                                       M_BR(branchdisp);
+                                       break;
+                               case BRANCH_NAN:
+                                       vm_abort("emit_branch: long BRANCH_NAN");
+                                       break;
+                               default:
+                                       vm_abort("emit_branch: unknown condition %d", condition);
+                               }
+                       }
                }
                else {
                        switch (condition) {