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The standard calling convention of AVR is documented at
https://gcc.gnu.org/wiki/avr-gcc#Calling_Convention
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D120475
Files:
clang/lib/Basic/Targets/AVR.cpp
clang/lib/Basic/Targets/AVR.h
clang/lib/CodeGen/TargetInfo.cpp
clang/test/CodeGen/avr/argument.c
Index: clang/test/CodeGen/avr/argument.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/avr/argument.c
@@ -0,0 +1,87 @@
+// RUN: %clang_cc1 -triple avr -target-cpu atmega328 -emit-llvm %s -o - \
+// RUN: | FileCheck %s --check-prefix AVR
+// RUN: %clang_cc1 -triple avr -target-cpu attiny40 -emit-llvm %s -o - \
+// RUN: | FileCheck %s --check-prefix TINY
+
+// NOTE: All arguments are passed in memory for functions with variable arguments.
+// AVR: define {{.*}} i16 @foo_varargs(i16* {{.*}} %0, i16* {{.*}} %1, ...)
+// TINY: define {{.*}} i16 @foo_varargs(i16* {{.*}} %0, i16* {{.*}} %1, ...)
+int foo_varargs(int a, int b, ...) {
+ return a + b;
+}
+
+// NOTE: A 10-byte argument is passed in registers on avr but in memory on avrtiny.
+// AVR: define {{.*}} i16 @foo0([10 x i8] {{.*}})
+// TINY: define {{.*}} i16 @foo0(%struct.s10* {{.*}})
+struct s10 {
+ char arr[10];
+};
+int foo0(struct s10 v) {
+ return v.arr[0] + v.arr[1];
+}
+
+// NOTE: The 8-byte argument is always passed in registers. The other arguments are passed
+// NOTE: in registers on avr but in memory on avrtiny.
+// AVR: define {{.*}} i16 @foo1([8 x i8] {{.*}}, i16 {{.*}}, i32 {{.*}})
+// TINY: define {{.*}} i16 @foo1([8 x i8] {{.*}}, i16* {{.*}}, i32* {{.*}})
+struct s8 {
+ char arr[8];
+};
+int foo1(struct s8 a, int b, long c) {
+ return a.arr[b + c];
+}
+
+// NOTE: All arguments are passed in registers.
+// AVR: define {{.*}} i32 @foo2(i32 {{.*}}, i16 {{.*}}, i16 {{.*}})
+// TINY: define {{.*}} i32 @foo2(i32 {{.*}}, i16 {{.*}}, i16 {{.*}})
+long foo2(long a, int b, int c) {
+ return a + b + c;
+}
+
+// NOTE: The arguments a&b are passed in registers. The argument c is passed
+// NOTE: in register on avr but in memory on avrtiny.
+// AVR: define {{.*}} i32 @foo3(i32 {{.*}}, i16 {{.*}}, i32 {{.*}})
+// TINY: define {{.*}} i32 @foo3(i32 {{.*}}, i16 {{.*}}, i32* {{.*}})
+long foo3(long a, int b, long c) {
+ return a + b + c;
+}
+
+// NOTE: An int8 arguments will be extended to i16 if passed in registers.
+// AVR: define {{.*}} i16 @foo4(i8 {{.*}} signext {{.*}}, i8 {{.*}} zeroext {{.*}})
+// TINY: define {{.*}} i16 @foo4(i8 {{.*}} signext {{.*}}, i8 {{.*}} zeroext {{.*}})
+int foo4(char a, unsigned char b) {
+ return (int)a + (int)b;
+}
+
+// NOTE: On avrtiny, although the first argument only costs 7 registers, the second
+// NOTE: argument (with i8 type) is passed in memory.
+// TINY: define {{.*}} i16 @foo5([7 x i8] {{.*}}, i8* {{.*}})
+struct s7 {
+ char arr[7];
+};
+int foo5(struct s7 a, char b) {
+ return a.arr[b];
+}
+
+// NOTE: On avr, although the first argument only costs 17 registers, the second
+// NOTE: argument (with i8 type) is passed in memory.
+// AVR: define {{.*}} i16 @foo6([17 x i8] {{.*}}, i8* {{.*}})
+struct s17 {
+ char arr[17];
+};
+int foo6(struct s17 a, char b) {
+ return a.arr[b];
+}
+
+// NOTE: On avr, all arguments are passed in registers.
+// AVR: define {{.*}} i32 @foo7(i32 {{.*}}, i32 {{.*}}, i32 {{.*}}, i32 {{.*}}, i16 {{.*}})
+long foo7(long a, long b, long c, long d, int e) {
+ return a + b + c + d + e;
+}
+
+// NOTE: On avr, the arguments a&b&c&d are passed in registers, but e is
+// NOTE: passed in memory.
+// AVR: define {{.*}} i32 @foo8(i32 {{.*}}, i32 {{.*}}, i32 {{.*}}, i32 {{.*}}, i32* {{.*}})
+long foo8(long a, long b, long c, long d, long e) {
+ return a + b + c + d + e;
+}
Index: clang/lib/CodeGen/TargetInfo.cpp
===================================================================
--- clang/lib/CodeGen/TargetInfo.cpp
+++ clang/lib/CodeGen/TargetInfo.cpp
@@ -33,6 +33,7 @@
#include "llvm/IR/IntrinsicsNVPTX.h"
#include "llvm/IR/IntrinsicsS390.h"
#include "llvm/IR/Type.h"
+#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm> // std::sort
@@ -8273,8 +8274,14 @@
namespace {
class AVRABIInfo : public DefaultABIInfo {
+private:
+ // The total amount of registers can be used to pass parameters. It is 18 on
+ // AVR, or 8 on AVRTiny.
+ unsigned ParamRegs;
+
public:
- AVRABIInfo(CodeGenTypes &CGT) : DefaultABIInfo(CGT) {}
+ AVRABIInfo(CodeGenTypes &CGT, unsigned N)
+ : DefaultABIInfo(CGT), ParamRegs(N) {}
ABIArgInfo classifyReturnType(QualType Ty) const {
// A return struct with size less than or equal to 8 bytes is returned
@@ -8285,20 +8292,55 @@
return DefaultABIInfo::classifyReturnType(Ty);
}
- // Just copy the original implementation of DefaultABIInfo::computeInfo(),
- // since DefaultABIInfo::classify{Return,Argument}Type() are not virtual.
+ ABIArgInfo classifyArgumentType(QualType Ty, unsigned &NumRegs) const {
+ unsigned TySize = getContext().getTypeSize(Ty);
+
+ // An int8 type argument always occupies two registers like an int16.
+ if (TySize == 8 && NumRegs >= 2) {
+ NumRegs -= 2;
+ return ABIArgInfo::getExtend(Ty);
+ }
+
+ // If the argument size is an odd number of bytes, round up the size
+ // to the next even number.
+ TySize = llvm::alignTo(TySize, 16);
+
+ // Any type including an array/struct type can be passed in rgisters,
+ // if there are enough registers left.
+ if (TySize <= NumRegs * 8) {
+ NumRegs -= TySize / 8;
+ return ABIArgInfo::getDirect();
+ }
+
+ // An argument is passed either completely in registers or completely in
+ // memory. Since there are not enough registers left, current argument
+ // and all other unprocessed arguments should be passed in memory.
+ NumRegs = 0;
+ return ABIInfo::getNaturalAlignIndirect(Ty);
+ }
+
void computeInfo(CGFunctionInfo &FI) const override {
+ // Decide the return type.
if (!getCXXABI().classifyReturnType(FI))
FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
+ // Decide each argument type.
+ unsigned NumRegs = ParamRegs;
for (auto &I : FI.arguments())
- I.info = classifyArgumentType(I.type);
+ if (FI.isVariadic())
+ // Arguments of varargs functions are passed on the stack.
+ // This applies even to the named arguments.
+ I.info = ABIInfo::getNaturalAlignIndirect(I.type);
+ else
+ // Process each argument according to the ABI is avr or avrtiny.
+ // Total 18 registers can be used on avr and 8 ones on avrtiny.
+ I.info = classifyArgumentType(I.type, NumRegs);
}
};
class AVRTargetCodeGenInfo : public TargetCodeGenInfo {
public:
- AVRTargetCodeGenInfo(CodeGenTypes &CGT)
- : TargetCodeGenInfo(std::make_unique<AVRABIInfo>(CGT)) {}
+ AVRTargetCodeGenInfo(CodeGenTypes &CGT, unsigned N)
+ : TargetCodeGenInfo(std::make_unique<AVRABIInfo>(CGT, N)) {}
LangAS getGlobalVarAddressSpace(CodeGenModule &CGM,
const VarDecl *D) const override {
@@ -11271,8 +11313,12 @@
case llvm::Triple::mips64el:
return SetCGInfo(new MIPSTargetCodeGenInfo(Types, false));
- case llvm::Triple::avr:
- return SetCGInfo(new AVRTargetCodeGenInfo(Types));
+ case llvm::Triple::avr: {
+ // R8 ~ R25 are used to pass parameters on avr, while R18 ~ R25
+ // are used on avrtiny.
+ unsigned N = getTarget().getABI() == "avrtiny" ? 8 : 18;
+ return SetCGInfo(new AVRTargetCodeGenInfo(Types, N));
+ }
case llvm::Triple::aarch64:
case llvm::Triple::aarch64_32:
Index: clang/lib/Basic/Targets/AVR.h
===================================================================
--- clang/lib/Basic/Targets/AVR.h
+++ clang/lib/Basic/Targets/AVR.h
@@ -74,8 +74,7 @@
static const char *const GCCRegNames[] = {
"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9",
"r10", "r11", "r12", "r13", "r14", "r15", "r16", "r17", "r18", "r19",
- "r20", "r21", "r22", "r23", "r24", "r25", "X", "Y", "Z", "SP"
- };
+ "r20", "r21", "r22", "r23", "r24", "r25", "X", "Y", "Z", "SP"};
return llvm::makeArrayRef(GCCRegNames);
}
@@ -169,15 +168,12 @@
bool isValidCPUName(StringRef Name) const override;
void fillValidCPUList(SmallVectorImpl<StringRef> &Values) const override;
- bool setCPU(const std::string &Name) override {
- bool isValid = isValidCPUName(Name);
- if (isValid)
- CPU = Name;
- return isValid;
- }
+ bool setCPU(const std::string &Name) override;
+ StringRef getABI() const override { return ABI; }
protected:
std::string CPU;
+ StringRef ABI;
};
} // namespace targets
Index: clang/lib/Basic/Targets/AVR.cpp
===================================================================
--- clang/lib/Basic/Targets/AVR.cpp
+++ clang/lib/Basic/Targets/AVR.cpp
@@ -24,7 +24,8 @@
struct LLVM_LIBRARY_VISIBILITY MCUInfo {
const char *Name;
const char *DefineName;
- const int NumFlashBanks; // -1 means the device does not support LPM/ELPM.
+ const int NumFlashBanks; // Set to 0 for the devices do not support LPM/ELPM.
+ bool IsTiny; // Set to true for the devices belong to the avrtiny family.
};
// This list should be kept up-to-date with AVRDevices.td in LLVM.
@@ -267,14 +268,14 @@
{"atxmega128a1", "__AVR_ATxmega128A1__", 2},
{"atxmega128a1u", "__AVR_ATxmega128A1U__", 2},
{"atxmega128a4u", "__AVR_ATxmega128A4U__", 2},
- {"attiny4", "__AVR_ATtiny4__", 0},
- {"attiny5", "__AVR_ATtiny5__", 0},
- {"attiny9", "__AVR_ATtiny9__", 0},
- {"attiny10", "__AVR_ATtiny10__", 0},
- {"attiny20", "__AVR_ATtiny20__", 0},
- {"attiny40", "__AVR_ATtiny40__", 0},
- {"attiny102", "__AVR_ATtiny102__", 0},
- {"attiny104", "__AVR_ATtiny104__", 0},
+ {"attiny4", "__AVR_ATtiny4__", 0, true},
+ {"attiny5", "__AVR_ATtiny5__", 0, true},
+ {"attiny9", "__AVR_ATtiny9__", 0, true},
+ {"attiny10", "__AVR_ATtiny10__", 0, true},
+ {"attiny20", "__AVR_ATtiny20__", 0, true},
+ {"attiny40", "__AVR_ATtiny40__", 0, true},
+ {"attiny102", "__AVR_ATtiny102__", 0, true},
+ {"attiny104", "__AVR_ATtiny104__", 0, true},
{"attiny202", "__AVR_ATtiny202__", 1},
{"attiny402", "__AVR_ATtiny402__", 1},
{"attiny204", "__AVR_ATtiny204__", 1},
@@ -325,6 +326,27 @@
Values.push_back(Info.Name);
}
+bool AVRTargetInfo::setCPU(const std::string &Name) {
+ // Set the ABI and CPU fields if parameter Name is a family name.
+ if (llvm::is_contained(ValidFamilyNames, Name)) {
+ CPU = Name;
+ ABI = Name == "avrtiny" ? "avrtiny" : "avr";
+ return true;
+ }
+
+ // Set the ABI field if parameter Name is a device name.
+ auto It = llvm::find_if(
+ AVRMcus, [&](const MCUInfo &Info) { return Info.Name == Name; });
+ if (It != std::end(AVRMcus)) {
+ CPU = Name;
+ ABI = It->IsTiny ? "avrtiny" : "avr";
+ return true;
+ }
+
+ // Parameter Name is neither valid family name or valid device name.
+ return false;
+}
+
void AVRTargetInfo::getTargetDefines(const LangOptions &Opts,
MacroBuilder &Builder) const {
Builder.defineMacro("AVR");
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