[clang][Sparc] Fix __builtin_extract_return_addr etc.

While investigating the failures of `symbolize_pc.cpp` and
`symbolize_pc_inline.cpp` on SPARC (both Solaris and Linux), I noticed that
`__builtin_extract_return_addr` is a no-op in `clang` on all targets, while
`gcc` has non-default implementations for arm, mips, s390, and sparc.

This patch provides the SPARC implementation.  For background see
`SparcISelLowering.cpp` (`SparcTargetLowering::LowerReturn_32`), the SPARC
psABI p.3-12, `%i7` and p.3-16/17, and SCD 2.4.1, p.3P-10, `%i7` and
p.3P-15.

Tested (after enabling the `sanitizer_common` tests on SPARC) on
`sparcv9-sun-solaris2.11`.

Differential Revision: https://reviews.llvm.org/D91607

(cherry picked from commit efdd0a2)

Author: rorth

clang/lib/CodeGen/TargetInfo.cpp

@@ -9474,6 +9474,28 @@ class SparcV8TargetCodeGenInfo : public TargetCodeGenInfo {
 public:
   SparcV8TargetCodeGenInfo(CodeGenTypes &CGT)
       : TargetCodeGenInfo(std::make_unique<SparcV8ABIInfo>(CGT)) {}
+
+  llvm::Value *decodeReturnAddress(CodeGen::CodeGenFunction &CGF,
+                                   llvm::Value *Address) const override {
+    int Offset;
+    if (isAggregateTypeForABI(CGF.CurFnInfo->getReturnType()))
+      Offset = 12;
+    else
+      Offset = 8;
+    return CGF.Builder.CreateGEP(CGF.Int8Ty, Address,
+                                 llvm::ConstantInt::get(CGF.Int32Ty, Offset));
+  }
+
+  llvm::Value *encodeReturnAddress(CodeGen::CodeGenFunction &CGF,
+                                   llvm::Value *Address) const override {
+    int Offset;
+    if (isAggregateTypeForABI(CGF.CurFnInfo->getReturnType()))
+      Offset = -12;
+    else
+      Offset = -8;
+    return CGF.Builder.CreateGEP(CGF.Int8Ty, Address,
+                                 llvm::ConstantInt::get(CGF.Int32Ty, Offset));
+  }
 };
 } // end anonymous namespace
 
@@ -9748,6 +9770,18 @@ class SparcV9TargetCodeGenInfo : public TargetCodeGenInfo {
 
   bool initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF,
                                llvm::Value *Address) const override;
+
+  llvm::Value *decodeReturnAddress(CodeGen::CodeGenFunction &CGF,
+                                   llvm::Value *Address) const override {
+    return CGF.Builder.CreateGEP(CGF.Int8Ty, Address,
+                                 llvm::ConstantInt::get(CGF.Int32Ty, 8));
+  }
+
+  llvm::Value *encodeReturnAddress(CodeGen::CodeGenFunction &CGF,
+                                   llvm::Value *Address) const override {
+    return CGF.Builder.CreateGEP(CGF.Int8Ty, Address,
+                                 llvm::ConstantInt::get(CGF.Int32Ty, -8));
+  }
 };
 } // end anonymous namespace
 

clang/test/CodeGen/builtins-sparc.c

@@ -1,10 +1,29 @@
 // REQUIRES: sparc-registered-target
 // RUN: %clang_cc1 -triple sparc-unknown-unknown -emit-llvm %s -o - | FileCheck %s
-// RUN: %clang_cc1 -triple sparc64-unknown-unknown -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple sparc64-unknown-unknown -emit-llvm %s -o - | FileCheck -check-prefix CHECK-V9 %s
 
 void test_eh_return_data_regno(void)
 {
   volatile int res;
-  res = __builtin_eh_return_data_regno(0);  // CHECK: store volatile i32 24
-  res = __builtin_eh_return_data_regno(1);  // CHECK: store volatile i32 25
+  res = __builtin_eh_return_data_regno(0);  // CHECK,CHECKV9: store volatile i32 24
+  res = __builtin_eh_return_data_regno(1);  // CHECK,CHECKV9: store volatile i32 25
+}
+
+void *test_extract_return_address(void)
+{
+  // CHECK,CHECKV9: getelementptr i8, i8* %0, i32 8
+  return __builtin_extract_return_addr(__builtin_return_address(0));
+}
+
+struct s {
+  void *p;
+};
+
+struct s test_extract_struct_return_address(void)
+{
+  struct s s;
+  // CHECK:    getelementptr i8, i8* %0, i32 12
+  // CHECK-V9: getelementptr i8, i8* %0, i32 8
+  s.p = __builtin_extract_return_addr(__builtin_return_address(0));
+  return s;
 }