Debug: Implement getArgument() and function skipping for ARM.

In the process make add skipFuction() to handle isa specific function skipping
instead of ifdefs and other ugliness. For almost all ABIs, 64 bit arguments can
only start in even registers.  Size is now passed to getArgument() so that 32
bit systems can make decisions about register selection for 64 bit arguments.
The number argument is now passed by reference because getArgument() will need
to change it based on the size of the argument and the current argument number.

For ARM, if the argument number is odd and a 64-bit register is requested the
number must first be incremented to because all 64 bit arguments are passed
in an even argument register. Then the number will be incremented again to
access both halves of the argument.

2 files changed, 14 insertions, 2 deletions

diff --git a/src/arch/sparc/utility.cc b/src/arch/sparc/utility.cc
index 9a062e841..e14be48e2 100644
--- a/src/arch/sparc/utility.cc
+++ b/src/arch/sparc/utility.cc
@@ -45,7 +45,7 @@ namespace SparcISA {
 //the sixth are passed on the stack past the 16 word window save area,
 //space for the struct/union return pointer, and space reserved for the
 //first 6 arguments which the caller may use but doesn't have to.
-uint64_t getArgument(ThreadContext *tc, int number, bool fp) {
+uint64_t getArgument(ThreadContext *tc, int &number, uint8_t size, bool fp) {
 #if FULL_SYSTEM
     const int NumArgumentRegs = 6;
     if (number < NumArgumentRegs) {
@@ -219,6 +219,16 @@ copyRegs(ThreadContext *src, ThreadContext *dest)
 }
 
 void
+skipFunction(ThreadContext *tc)
+{
+    Addr newpc = tc->readIntReg(ReturnAddressReg);
+    tc->setPC(newpc);
+    tc->setNextPC(tc->readPC() + sizeof(TheISA::MachInst));
+    tc->setNextPC(tc->readNextPC() + sizeof(TheISA::MachInst));
+}
+
+
+void
 initCPU(ThreadContext *tc, int cpuId)
 {
     static Fault por = new PowerOnReset();
diff --git a/src/arch/sparc/utility.hh b/src/arch/sparc/utility.hh
index 70044a6c2..39e23aa26 100644
--- a/src/arch/sparc/utility.hh
+++ b/src/arch/sparc/utility.hh
@@ -41,7 +41,7 @@
 
 namespace SparcISA
 {
-    uint64_t getArgument(ThreadContext *tc, int number, bool fp);
+    uint64_t getArgument(ThreadContext *tc, int &number, uint8_t size, bool fp);
 
     static inline bool
     inUserMode(ThreadContext *tc)
@@ -75,6 +75,8 @@ namespace SparcISA
 
     void copyMiscRegs(ThreadContext *src, ThreadContext *dest);
 
+    void skipFunction(ThreadContext *tc);
+
 } // namespace SparcISA
 
 #endif