llvm-dwarfdump: Improve/fix pretty printing of array dimensions

This is to address post-commit feedback from Paul Robinson on r348954.

The original commit misinterprets count and upper bound as the same thing (I thought I saw GCC producing an upper bound the same as Clang's count, but GCC correctly produces an upper bound that's one less than the count (in C, that is, where arrays are zero indexed)).

I want to preserve the C-like output for the common case, so in the absence of a lower bound the count (or one greater than the upper bound) is rendered between []. In the trickier cases, where a lower bound is specified, a half-open range is used (eg: lower bound 1, count 2 would be "[1, 3)" and an unknown parts use a '?' (eg: "[1, ?)" or "[?, 7)" or "[?, ? + 3)").

Reviewers: aprantl, probinson, JDevlieghere

Differential Revision: https://reviews.llvm.org/D55721

llvm-svn: 349670

1 files changed, 59 insertions, 3 deletions

diff --git a/llvm/test/tools/llvm-dwarfdump/X86/prettyprint_types.s b/llvm/test/tools/llvm-dwarfdump/X86/prettyprint_types.s
index b3e871e7c82..afeee4cfba6 100644
--- a/llvm/test/tools/llvm-dwarfdump/X86/prettyprint_types.s
+++ b/llvm/test/tools/llvm-dwarfdump/X86/prettyprint_types.s
@@ -19,13 +19,41 @@
 # CHECK:   DW_AT_type{{.*}}"int foo::*"
 
 # array_type
-# Testing lower_bound, upper_bound, lower and upper, lower and count, and count separately.
-# CHECK:   DW_AT_type{{.*}}"int[1-][2][1-2][1-3][2]"
+# CHECK:   DW_AT_type{{.*}}"int
+# Testing with a default lower bound of 0 and the following explicit bounds:
+#   lower_bound(1)
+# CHECK-NOT: {{.}}
+# CHECK-SAME: {{\[}}[1, ?)]
+#   upper_bound(2)
+# CHECK-NOT: {{.}}
+# CHECK-SAME: [3]
+#   lower(1) and upper(2)
+# CHECK-NOT: {{.}}
+# CHECK-SAME: {{\[}}[1, 3)]
+#   lower(1) and count(3)
+# CHECK-NOT: {{.}}
+# CHECK-SAME: {{\[}}[1, 4)]
+#   lower(0) and count(4) - testing that the lower bound matching language
+#   default is not rendered
+# CHECK-NOT: {{.}}
+# CHECK-SAME: [4]
+#   count(2)
+# CHECK-SAME: [2]
+#   no attributes
+# CHECK-NOT: {{.}}
+# CHECK-SAME: []{{"\)$}}
+
 
 # subroutine types
 # CHECK:   DW_AT_type{{.*}}"int()"
 # CHECK:   DW_AT_type{{.*}}"void(int)"
 # CHECK:   DW_AT_type{{.*}}"void(int, int)"
+
+# array_type with a language with a default lower bound of 1 instead of 0 and
+# an upper bound of 2. This describes an array with 2 elements (whereas with a
+# default lower bound of 0 it would be an array of 3 elements)
+# CHECK: DW_AT_type{{.*}}"int[2]"
+
 	.section	.debug_str,"MS",@progbits,1
 .Lint_name:
 	.asciz	"int"
@@ -155,6 +183,11 @@
 	.byte	19                      # DW_FORM_ref4
 	.byte	0                       # EOM(1)
 	.byte	0                       # EOM(2)
+	.byte	18                      # Abbreviation Code
+	.byte	0x21                    # DW_TAG_subrange_type
+	.byte	0                       # DW_CHILDREN_no
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
 	.byte	0                       # EOM(3)
 	.section	.debug_info,"",@progbits
 .Lcu_begin:
@@ -196,9 +229,13 @@
 	.byte   2                       #     DW_AT_upper_bound
 	.byte	12                      #   DW_AT_subrange_type
 	.byte   1                       #     DW_AT_lower_bound
-	.byte   2                       #     DW_AT_count
+	.byte   3                       #     DW_AT_count
+	.byte	12                      #   DW_AT_subrange_type
+	.byte   0                       #     DW_AT_lower_bound
+	.byte   4                       #     DW_AT_count
 	.byte	13                      #   DW_AT_subrange_type
 	.byte   2                       #     DW_AT_count
+	.byte	18                      #   DW_AT_subrange_type
 	.byte	0                       # End Of Children Mark
 .Lsub_int_empty_type:
 	.byte	15                      # DW_TAG_subroutine_type
@@ -236,3 +273,22 @@
 	.long	.Lsub_void_int_int_type - .Lcu_begin #   DW_AT_type
 	.byte	0                       # End Of Children Mark
 .Lunit_end:
+.Lcu2_begin:
+	.long	.Lcu2_unit_end - .Lcu2_unit_start # Length of Unit
+.Lcu2_unit_start:
+	.short	4                       # DWARF version number
+	.long	.debug_abbrev           # Offset Into Abbrev. Section
+	.byte	8                       # Address Size (in bytes)
+	.byte	1                       # DW_TAG_compile_unit
+	.short	13                      #   DW_AT_language
+.Lcu2_int_type:
+	.byte	2                       # DW_TAG_base_type
+	.long	.Lint_name              #   DW_AT_name
+.Lcu2_array_type:
+	.byte	8                       # DW_TAG_array_type
+	.long	.Lcu2_int_type - .Lcu2_begin #   DW_AT_type
+	.byte	10                      #   DW_AT_subrange_type
+	.byte   2                       #     DW_AT_upper_bound
+	.byte	3                       # DW_TAG_variable
+	.long	.Lcu2_array_type - .Lcu2_begin #   DW_AT_type
+.Lcu2_unit_end: