Prevent corruption to rax during stack alignment on x86-64

dyninst · Oct 2, 2019 · cecd1a8 · cecd1a8
1 parent b69554b
commit cecd1a8
Showing 1 changed file with 1 addition and 5 deletions.
diff --git a/dyninstAPI/src/emit-x86.C b/dyninstAPI/src/emit-x86.C
@@ -2420,11 +2420,7 @@ void EmitterAMD64::emitStackAlign(int offset, codeGen &gen)
    int saveSlot2 =    8 + AMD64_STACK_ALIGNMENT;
 
    bool saveFlags = false;
-   Register scratch =  gen.rs()->getScratchRegister(gen);
-   // If we cannot allocate a scratch register, use RAX.
-   // It will be restored at the end anyway
-   if (scratch == REG_NULL)
-      scratch = REGNUM_RAX;
+   Register scratch = REGNUM_RAX;
 
    if (gen.rs()->checkVolatileRegisters(gen, registerSlot::live)) {
       saveFlags = true;   // We need to save the flags register