arch: Get rid of the (Big|Little)EndianGuest namespaces.

These namespaces were used to set up an environment/context where there
was an implicit guest namespace. This is an issue when there may be
multiple guest endiannesses which might be different. In cases where
we don't know what the guest endianness is, we can't rely on it being
an implicit part of our context since that would be ambiguous. In cases
where we do know, for instance in ISA specific code, we can just use
the endianness specific version that's appropriate for that context.

This also (somewhat) removes the assumption that there is a single
endianness that applies for a particular ISA. Practically speaking this
assumption will probably still stand though, since there would likely
be a non-trivial performance penalty to apply a configurable endianness
instead of a fixed one the compiler can optomize/remove.

Change-Id: I2dff338b58726d724f387388efe32d9233885680
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22374
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

13 files changed, 8 insertions, 65 deletions

diff --git a/src/arch/alpha/isa_traits.hh b/src/arch/alpha/isa_traits.hh
index 61688b5c8..22fc0c454 100644
--- a/src/arch/alpha/isa_traits.hh
+++ b/src/arch/alpha/isa_traits.hh
@@ -32,8 +32,6 @@
 #ifndef __ARCH_ALPHA_ISA_TRAITS_HH__
 #define __ARCH_ALPHA_ISA_TRAITS_HH__
 
-namespace LittleEndianGuest {}
-
 #include "arch/alpha/ipr.hh"
 #include "arch/alpha/types.hh"
 #include "base/types.hh"
@@ -41,7 +39,7 @@ namespace LittleEndianGuest {}
 
 namespace AlphaISA {
 
-using namespace LittleEndianGuest;
+const ByteOrder GuestByteOrder = LittleEndianByteOrder;
 
 StaticInstPtr decodeInst(ExtMachInst);
 
diff --git a/src/arch/arm/isa_traits.hh b/src/arch/arm/isa_traits.hh
index 5763e7747..3427837d7 100644
--- a/src/arch/arm/isa_traits.hh
+++ b/src/arch/arm/isa_traits.hh
@@ -49,11 +49,9 @@
 #include "base/types.hh"
 #include "cpu/static_inst_fwd.hh"
 
-namespace LittleEndianGuest {}
-
 namespace ArmISA
 {
-    using namespace LittleEndianGuest;
+    const ByteOrder GuestByteOrder = LittleEndianByteOrder;
 
     StaticInstPtr decodeInst(ExtMachInst);
 
diff --git a/src/arch/mips/isa_traits.hh b/src/arch/mips/isa_traits.hh
index 6e08c7e85..8dd7054ba 100644
--- a/src/arch/mips/isa_traits.hh
+++ b/src/arch/mips/isa_traits.hh
@@ -38,12 +38,10 @@
 #include "base/types.hh"
 #include "cpu/static_inst_fwd.hh"
 
-namespace LittleEndianGuest {}
-
 namespace MipsISA
 {
 
-using namespace LittleEndianGuest;
+const ByteOrder GuestByteOrder = LittleEndianByteOrder;
 
 StaticInstPtr decodeInst(ExtMachInst);
 
diff --git a/src/arch/mips/system.cc b/src/arch/mips/system.cc
index 9967aa82c..3d2be34c8 100644
--- a/src/arch/mips/system.cc
+++ b/src/arch/mips/system.cc
@@ -41,8 +41,6 @@
 #include "params/MipsSystem.hh"
 #include "sim/byteswap.hh"
 
-using namespace LittleEndianGuest;
-
 MipsSystem::MipsSystem(Params *p) : System(p)
 {
 }
diff --git a/src/arch/power/isa_traits.hh b/src/arch/power/isa_traits.hh
index 9afe6803a..020913397 100644
--- a/src/arch/power/isa_traits.hh
+++ b/src/arch/power/isa_traits.hh
@@ -39,12 +39,10 @@
 #include "base/types.hh"
 #include "cpu/static_inst_fwd.hh"
 
-namespace BigEndianGuest {}
-
 namespace PowerISA
 {
 
-using namespace BigEndianGuest;
+const ByteOrder GuestByteOrder = BigEndianByteOrder;
 
 StaticInstPtr decodeInst(ExtMachInst);
 
diff --git a/src/arch/riscv/isa_traits.hh b/src/arch/riscv/isa_traits.hh
index abafad2e2..f69e71994 100644
--- a/src/arch/riscv/isa_traits.hh
+++ b/src/arch/riscv/isa_traits.hh
@@ -50,12 +50,10 @@
 #include "base/types.hh"
 #include "cpu/static_inst_fwd.hh"
 
-namespace LittleEndianGuest {}
-
 namespace RiscvISA
 {
 
-using namespace LittleEndianGuest;
+const ByteOrder GuestByteOrder = LittleEndianByteOrder;
 
 const Addr PageShift = 12;
 const Addr PageBytes = ULL(1) << PageShift;
diff --git a/src/arch/riscv/system.cc b/src/arch/riscv/system.cc
index 88d6251cc..2017eed98 100644
--- a/src/arch/riscv/system.cc
+++ b/src/arch/riscv/system.cc
@@ -42,8 +42,6 @@
 #include "params/RiscvSystem.hh"
 #include "sim/byteswap.hh"
 
-using namespace LittleEndianGuest;
-
 RiscvSystem::RiscvSystem(Params *p)
     : System(p),
       _isBareMetal(p->bare_metal),
diff --git a/src/arch/sparc/isa_traits.hh b/src/arch/sparc/isa_traits.hh
index f42cdb9f5..c942a6edc 100644
--- a/src/arch/sparc/isa_traits.hh
+++ b/src/arch/sparc/isa_traits.hh
@@ -37,12 +37,10 @@
 #include "base/types.hh"
 #include "cpu/static_inst_fwd.hh"
 
-namespace BigEndianGuest {}
-
 namespace SparcISA
 {
-// This makes sure the big endian versions of certain functions are used.
-using namespace BigEndianGuest;
+
+const ByteOrder GuestByteOrder = BigEndianByteOrder;
 
 const Addr PageShift = 13;
 const Addr PageBytes = ULL(1) << PageShift;
diff --git a/src/arch/sparc/system.cc b/src/arch/sparc/system.cc
index 2d79ab4c3..1a809beba 100644
--- a/src/arch/sparc/system.cc
+++ b/src/arch/sparc/system.cc
@@ -38,8 +38,6 @@
 #include "params/SparcSystem.hh"
 #include "sim/byteswap.hh"
 
-using namespace BigEndianGuest;
-
 namespace
 {
 
diff --git a/src/arch/x86/isa_traits.hh b/src/arch/x86/isa_traits.hh
index 158e2f9e4..3dbacd056 100644
--- a/src/arch/x86/isa_traits.hh
+++ b/src/arch/x86/isa_traits.hh
@@ -45,13 +45,9 @@
 #include "base/compiler.hh"
 #include "base/types.hh"
 
-namespace LittleEndianGuest {}
-
 namespace X86ISA
 {
-    //This makes sure the little endian version of certain functions
-    //are used.
-    using namespace LittleEndianGuest;
+    const ByteOrder GuestByteOrder = LittleEndianByteOrder;
 
     const Addr PageShift = 12;
     const Addr PageBytes = ULL(1) << PageShift;
diff --git a/src/arch/x86/linux/system.cc b/src/arch/x86/linux/system.cc
index b4cd70e30..0aa94a225 100644
--- a/src/arch/x86/linux/system.cc
+++ b/src/arch/x86/linux/system.cc
@@ -48,7 +48,6 @@
 #include "params/LinuxX86System.hh"
 #include "sim/byteswap.hh"
 
-using namespace LittleEndianGuest;
 using namespace X86ISA;
 
 LinuxX86System::LinuxX86System(Params *p)
diff --git a/src/arch/x86/system.cc b/src/arch/x86/system.cc
index 704a37aba..096f10f5e 100644
--- a/src/arch/x86/system.cc
+++ b/src/arch/x86/system.cc
@@ -48,7 +48,6 @@
 #include "cpu/thread_context.hh"
 #include "params/X86System.hh"
 
-using namespace LittleEndianGuest;
 using namespace X86ISA;
 
 X86System::X86System(Params *p) :
diff --git a/src/sim/byteswap.hh b/src/sim/byteswap.hh
index 0b41c6779..6745e0060 100644
--- a/src/sim/byteswap.hh
+++ b/src/sim/byteswap.hh
@@ -169,37 +169,4 @@ inline T gtoh(T value, ByteOrder guest_byte_order)
         betoh(value) : letoh(value);
 }
 
-namespace BigEndianGuest
-{
-    const ByteOrder GuestByteOrder = BigEndianByteOrder;
-    template <typename T>
-    inline T gtole(T value) {return betole(value);}
-    template <typename T>
-    inline T letog(T value) {return letobe(value);}
-    template <typename T>
-    inline T gtobe(T value) {return value;}
-    template <typename T>
-    inline T betog(T value) {return value;}
-    template <typename T>
-    inline T htog(T value) {return htobe(value);}
-    template <typename T>
-    inline T gtoh(T value) {return betoh(value);}
-}
-
-namespace LittleEndianGuest
-{
-    const ByteOrder GuestByteOrder = LittleEndianByteOrder;
-    template <typename T>
-    inline T gtole(T value) {return value;}
-    template <typename T>
-    inline T letog(T value) {return value;}
-    template <typename T>
-    inline T gtobe(T value) {return letobe(value);}
-    template <typename T>
-    inline T betog(T value) {return betole(value);}
-    template <typename T>
-    inline T htog(T value) {return htole(value);}
-    template <typename T>
-    inline T gtoh(T value) {return letoh(value);}
-}
 #endif // __SIM_BYTE_SWAP_HH__