[llvm][dwarfdump] Add --child-tags option to filter by DWARF tags #165720
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@llvm/pr-subscribers-llvm-binary-utilities @llvm/pr-subscribers-debuginfo Author: Michael Buch (Michael137) ChangesThis patch adds a new option Motivating examples are:
For tags not known to dwarfdump, we pretend that the tag wasn't specified. Note, this flag only takes effect when Example: Full diff: https://github.com/llvm/llvm-project/pull/165720.diff 3 Files Affected:
diff --git a/llvm/include/llvm/DebugInfo/DIContext.h b/llvm/include/llvm/DebugInfo/DIContext.h
index e7e87bbfebf38..32ce4520dbca7 100644
--- a/llvm/include/llvm/DebugInfo/DIContext.h
+++ b/llvm/include/llvm/DebugInfo/DIContext.h
@@ -202,6 +202,8 @@ struct DIDumpOptions {
bool ShowAddresses = true;
bool ShowChildren = false;
bool ShowParents = false;
+ /// List of DWARF tags to filter children by.
+ llvm::SmallVector<unsigned> ChildTagsFilter;
bool ShowForm = false;
bool SummarizeTypes = false;
bool Verbose = false;
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
index db5cc37c93f90..7558fbda18459 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
@@ -676,7 +676,9 @@ void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
DIDumpOptions ChildDumpOpts = DumpOpts;
ChildDumpOpts.ShowParents = false;
while (Child) {
- Child.dump(OS, Indent + 2, ChildDumpOpts);
+ if (DumpOpts.ChildTagsFilter.empty() ||
+ llvm::is_contained(DumpOpts.ChildTagsFilter, Child.getTag()))
+ Child.dump(OS, Indent + 2, ChildDumpOpts);
Child = Child.getSibling();
}
}
diff --git a/llvm/tools/llvm-dwarfdump/llvm-dwarfdump.cpp b/llvm/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
index 79f05278c329d..eb5f8b4af95a6 100644
--- a/llvm/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
+++ b/llvm/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
@@ -14,6 +14,7 @@
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallVectorExtras.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/DebugInfo/DIContext.h"
#include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
@@ -241,6 +242,15 @@ static opt<bool>
cat(DwarfDumpCategory));
static alias ShowParentsAlias("p", desc("Alias for --show-parents."),
aliasopt(ShowParents), cl::NotHidden);
+
+static list<std::string>
+ ChildTags("child-tags",
+ desc("When --show-children is specified, show only DIEs with the "
+ "specified DWARF tags."),
+ value_desc("list of DWARF tags"), cat(DwarfDumpCategory));
+static alias TagsAlias("t", desc("Alias for --child-tags."),
+ aliasopt(ChildTags), cl::NotHidden);
+
static opt<bool>
ShowForm("show-form",
desc("Show DWARF form types after the DWARF attribute types."),
@@ -329,6 +339,13 @@ static cl::extrahelp
/// @}
//===----------------------------------------------------------------------===//
+static llvm::SmallVector<unsigned>
+makeTagVector(const list<std::string> &TagStrings) {
+ return llvm::map_to_vector(TagStrings, [](const std::string &Tag) {
+ return llvm::dwarf::getTag(Tag);
+ });
+}
+
static void error(Error Err) {
if (!Err)
return;
@@ -355,6 +372,7 @@ static DIDumpOptions getDumpOpts(DWARFContext &C) {
DumpOpts.ShowAddresses = !Diff;
DumpOpts.ShowChildren = ShowChildren;
DumpOpts.ShowParents = ShowParents;
+ DumpOpts.ChildTagsFilter = makeTagVector(ChildTags);
DumpOpts.ShowForm = ShowForm;
DumpOpts.SummarizeTypes = SummarizeTypes;
DumpOpts.Verbose = Verbose;
@@ -898,6 +916,12 @@ int main(int argc, char **argv) {
Find.empty() && !FindAllApple)
ShowChildren = true;
+ if (!ShowChildren && !ChildTags.empty()) {
+ WithColor::error()
+ << "incompatible arguments: --child-tags requires --show-children";
+ return 1;
+ }
+
// Defaults to a.out if no filenames specified.
if (InputFilenames.empty())
InputFilenames.push_back("a.out");
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Seems OK to me as a feature - though I wonder if we're getting to the point of "should have an arbitrary query language" for querying DWARF at this point? (did we ever end up with the json output for dwarfdump? perhaps that's the way to do it - dump to json and use jquery?) |
i had the exact same line of thought when i initially started implementing this. What nudged me over the edge was that i prefer looking at dwarfdump output over json, though that’s admittedly a selfish reason. Ultimately i thought, if it’s not too much of a maintenance burden, might as well. Of course there’s always complexity of how various options interact, which in this case seemed ok. A more involved querying feature (like filtering by attribute value/existence), which I’d love to have, is probably not worth adding to the current infrastructure because of how complex it would be to implement (afaict). But yea, happy to hear others chime in on usefulness/if it’s acceptable maintenance-wise, and whether there is appetite for something more complete. |
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I would have probably called it |
| @@ -202,6 +202,8 @@ struct DIDumpOptions { | |||
| bool ShowAddresses = true; | |||
| bool ShowChildren = false; | |||
| bool ShowParents = false; | |||
| /// List of DWARF tags to filter children by. | |||
| llvm::SmallVector<unsigned> ChildTagsFilter; | |||
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Given that this is going to be empty most of the time, maybe just use a vector or a SmallVector<0 or 1>?
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How are multiple ones separated?
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Like with other options, you specify the option multiple times. E.g., dwarfdump -t DW_TAG_foo -t DW_TAG_bar
Other options like --name behave the same
This patch adds a new option `--child-tags` (`-t` for short), which makes dwarfdump only dump children whose DWARF tag is in the list of tags specified by the user. Motivating examples are: * dumping all global variables in a CU * dumping all non-static data members of a structure * dumping all module import declarations of a CU * etc. For tags not known to dwarfdump, we pretend that the tag wasn't specified.
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This patch adds a new option
--child-tags(-tfor short), which makes dwarfdump only dump children whose DWARF tag is in the list of tags specified by the user.Motivating examples are:
For tags not known to dwarfdump, we pretend that the tag wasn't specified.
Note, this flag only takes effect when
--show-childrenis set (either explicitly or implicitly). We error out when trying to use the flag without dumping children.Example: