de3c8410d8
RFC on discourse: https://discourse.llvm.org/t/rfc-debug-info-for-coroutine-suspension-locations-take-2/86606 With this commit, we add `DILabel` debug infos to the resume points of a coroutine. Those labels can be used by debugging scripts to figure out the exact line and column at which a coroutine was suspended by looking up current `__coro_index` value inside the coroutines frame, and then searching for the corresponding label inside the coroutine's resume function. The DWARF information generated for such a label looks like: ``` 0x00000f71: DW_TAG_label DW_AT_name ("__coro_resume_1") DW_AT_decl_file ("generator-example.cpp") DW_AT_decl_line (5) DW_AT_decl_column (3) DW_AT_artificial (true) DW_AT_LLVM_coro_suspend_idx (0x01) DW_AT_low_pc (0x00000000000019be) ``` The labels can be mapped to their corresponding `__coro_idx` values either via their naming convention `__coro_resume_<N>` or using the new `DW_AT_LLVM_coro_suspend_idx` attribute. In gdb, those line numebrs can be looked up using `info line -function my_coroutine -label __coro_resume_1`. LLDB unfortunately does not understand DW_TAG_label debug information, yet. Given this is an artificial compiler-generated label, I did apply the DW_AT_artificial tag to it. The DWARFv5 standard only allows that tag on type and variable definitions, but this is a natural extension and was also blessed in the RFC on discourse. Also, this commit adds `DW_AT_decl_column` to labels, not only for coroutines but also for normal C and C++ labels. While not strictly necessary, I am doing so now because it would be harder to do so later without breaking the binary LLVM-IR format Drive-by fixes: While reading the existing test cases to understand how to write my own test case, I did a couple of small typo fixes and comment improvements
29 lines
833 B
C
29 lines
833 B
C
// This test will test the correctness of generating DILabel and
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// llvm.dbg.label when the label is in inlined functions.
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//
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// RUN: %clang_cc1 -O2 %s -o - -emit-llvm -debug-info-kind=limited | FileCheck %s
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inline int f1(int a, int b) {
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int sum;
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top:
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sum = a + b;
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return sum;
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}
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extern int ga, gb;
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int f2(void) {
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int result;
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result = f1(ga, gb);
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// CHECK: #dbg_label([[LABEL_METADATA:!.*]], [[LABEL_LOCATION:![0-9]+]]
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return result;
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}
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// CHECK: distinct !DISubprogram(name: "f1", {{.*}}, retainedNodes: [[ELEMENTS:!.*]])
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// CHECK: [[ELEMENTS]] = !{{{.*}}, [[LABEL_METADATA]]}
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// CHECK: [[LABEL_METADATA]] = !DILabel({{.*}}, name: "top", {{.*}}, line: 8, column: 1)
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// CHECK: [[INLINEDAT:!.*]] = distinct !DILocation(line: 18,
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// CHECK: [[LABEL_LOCATION]] = !DILocation(line: 8, {{.*}}, inlinedAt: [[INLINEDAT]])
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