[PATCH] D122584: [DebugInfo] Use DW_ATE_signed encoding when creating a Fortran array index type.

[Chih-Ping Chen via Phabricator via llvm-commits]

cchen15 added a comment.

For my experiment, I use the two files in the attachment: test-c.cpp is the main program. It calls the Fortran function DegCtoF in test.f90.

I follow the test strategy in test/DebugInfo/Generic/cross-cu-inlining.ll, and compile the program files this way:

  $ clang++ -g -c -emit-llvm test-c.cpp
  $ fortran-comp -g -c -emit-llvm test.f90

Since in test.bc the Fortran subroutine has the attribute noinline and optnone, I manually modify the .bc to replace noinline with alwaysinline and remove optnone. Then

  $ llvm-link test-c.bc test.bc -o com.bc
  $ opt -inline com.bc -o com-opt.bc
  $ llc --filetype=obj com-opt.bc
  $ clang++ -g -o com-opt.exe com-opt.o

I verify with gdb that the Fortran function is inlined and debugging works as expected.

  gdb) b 23
  warning: Could not recognize version of Intel Compiler in: "Intel(R) Fortran 22.0-1478"
  Breakpoint 1 at 0x401179: file test-c.cpp, line 23.
  (gdb) r
  Starting program: /localdisk2/cchen15/examples/tests/signed-encoding/lto/new/com-opt.exe 
  C/C++ and Fortran together!
  
  Breakpoint 1, main (argc=1, argv=0x7fffffff8c28) at test-c.cpp:23
  23	    DegCtoF(DegreesC, DegreesF, &N);
  (gdb) x/20i $pc
  => 0x401179 <main(int, char**)+73>:	lea    -0x30(%rbp),%rax
     0x40117d <main(int, char**)+77>:	lea    -0x60(%rbp),%rcx
     0x401181 <main(int, char**)+81>:	mov    %rax,-0x48(%rbp)
     0x401185 <main(int, char**)+85>:	mov    -0x48(%rbp),%rax
     0x401189 <main(int, char**)+89>:	mov    %rcx,-0x40(%rbp)
     0x40118d <main(int, char**)+93>:	mov    -0x40(%rbp),%rcx
     0x401191 <main(int, char**)+97>:	lea    -0x14(%rbp),%rdx
     0x401195 <main(int, char**)+101>:	mov    %rdx,-0x38(%rbp)
     0x401199 <main(int, char**)+105>:	mov    -0x38(%rbp),%rdx
     0x40119d <main(int, char**)+109>:	mov    (%rdx),%esi
     0x40119f <main(int, char**)+111>:	mov    %esi,-0x10(%rbp)
     0x4011a2 <main(int, char**)+114>:	movslq -0x10(%rbp),%rsi
     0x4011a6 <main(int, char**)+118>:	mov    %rsi,-0x78(%rbp)
     0x4011aa <main(int, char**)+122>:	movslq -0x10(%rbp),%rsi
     0x4011ae <main(int, char**)+126>:	mov    %rsi,-0x70(%rbp)
     0x4011b2 <main(int, char**)+130>:	mov    (%rdx),%edx
     0x4011b4 <main(int, char**)+132>:	mov    %edx,-0xc(%rbp)
     0x4011b7 <main(int, char**)+135>:	movl   $0x1,-0x8(%rbp)
     0x4011be <main(int, char**)+142>:	cmpl   $0x1,-0xc(%rbp)
     0x4011c2 <main(int, char**)+146>:	
      jl     0x401207 <main(int, char**)+215>
  (gdb) s
  DegCtoF (degc=..., degf=..., n=2) at test.f90:14
  14	subroutine DegCtoF(degC, degF, n)&
  (gdb) n
  24	    do i = 1, n
  (gdb) p/x $pc
  $1 = 0x4011b2

Last but not least, I do a dwarfdump on com-opt.exe and the signed encoding for the Fortran array index type is preserved:

  0x00000166:     DW_TAG_formal_parameter
                    DW_AT_name	("degc")
                    DW_AT_decl_file	("/iusers/cchen15/examples/tests/signed-encoding/lto/new/test.f90")
                    DW_AT_decl_line	(14)
                    DW_AT_type	(0x000001ac "REAL*8[]")
  ...
  0x000001ac:   DW_TAG_array_type
                  DW_AT_type	(0x000001b7 "REAL*8")
  
  0x000001b1:     DW_TAG_subrange_type
                    DW_AT_type	(0x000001be "__ARRAY_SIZE_TYPE__")
  
  0x000001b6:     NULL
  
  0x000001b7:   DW_TAG_base_type
                  DW_AT_name	("REAL*8")
                  DW_AT_encoding	(DW_ATE_float)
                  DW_AT_byte_size	(0x08)
  
  0x000001be:   DW_TAG_base_type
                  DW_AT_name	("__ARRAY_SIZE_TYPE__")
                  DW_AT_byte_size	(0x08)
                  DW_AT_encoding	(DW_ATE_signed)

The complete dwarfdump is in com-opt.exe.ddump.F22621459: test-c.cpp <https://reviews.llvm.org/F22621459>

F22621458: com-opt.exe.ddump <https://reviews.llvm.org/F22621458>

F22621457: test.f90 <https://reviews.llvm.org/F22621457>


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D122584/new/

https://reviews.llvm.org/D122584