llvm/clang/test/CodeGen/debug-info-extern-call.c

// When entry values are emitted, expect a subprogram for extern decls so that
// the dwarf generator can describe call site parameters at extern call sites.
//
// Initial implementation relied on the 'retainedTypes:' from the corresponding
// DICompileUnit, so we also ensure that we do not store the extern declaration
// subprogram into the 'retainedTypes:'.
//
// RUN: %clang -g -O2 -target x86_64-none-linux-gnu -S -emit-llvm %s -o - \
// RUN:   | FileCheck %s -check-prefix=DECLS-FOR-EXTERN

// Similarly, when the debugger tuning is gdb, expect a subprogram for extern
// decls so that the dwarf generator can describe information needed for tail
// call frame reconstrution.
//
// RUN: %clang -gdwarf-4 -O2 -target x86_64-none-linux-gnu -ggdb -S -emit-llvm %s -o - \
// RUN:   | FileCheck %s -check-prefix=DECLS-FOR-EXTERN
//
// Do not emit a subprogram for extern decls when entry values are disabled and
// the tuning is not set to gdb.
//
// RUN: %clang -gdwarf-4 -O2 -target x86_64-none-linux-gnu -gsce -S -emit-llvm %s -o - \
// RUN:   | FileCheck %s -check-prefix=NO-DECLS-FOR-EXTERN

// DECLS-FOR-EXTERN-NOT: !DICompileUnit({{.*}}retainedTypes: !{{[0-9]+}}
// DECLS-FOR-EXTERN: [[INT_TYPE:![0-9]+]] = !DIBasicType(name: "int",
// DECLS-FOR-EXTERN: !DISubprogram(name: "fn1"
// DECLS-FOR-EXTERN-SAME: type: [[FN1_TYPE:![0-9]+]],
// DECLS-FOR-EXTERN: [[FN1_TYPE]] = !DISubroutineType(types: [[FN1_TYPES:![0-9]+]])
// DECLS-FOR-EXTERN: [[FN1_TYPES]] = !{[[X_TYPE:![0-9]+]],
// DECLS-FOR-EXTERN: [[X_TYPE]] = !DIDerivedType(tag: DW_TAG_typedef, name: "x",
// DECLS-FOR-EXTERN-SAME: baseType: [[INT_TYPE]])
// DECLS-FOR-EXTERN: !DISubprogram(name: "memcmp"
// DECLS-FOR-EXTERN: !DISubprogram(name: "__some_reserved_name"

// NO-DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "fn1"
// NO-DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "memcmp"
// NO-DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "__some_reserved_name"

typedef int x;
extern x fn1(int a, int b);
extern int memcmp(const void *s1, const void *s2, unsigned long n);
extern void __some_reserved_name(void);

int fn2 (int *src, int *dst) {
  int x = 4, y = 5;
  int res = fn1(x, y);
  int res2 = memcmp(dst, src, res);
  __some_reserved_name();
  return res + res2;
}