[LLDB] Support exception breakpoints for plugin-provided languages #97675
Conversation
CommandObjectBreakpoint has a harcoded list of languages for which exception breakpoints can be enabled. I'm making this a bit more generic so that my Mojo plugin can get this feature. Basically, I'm adding a new overridable method `Language::SupportsExceptionBreakpoints` that can be used by language plugins to determine whether they support this feature or not. This method is used in addition to the hardcoded list and, as an example, I'm using it for the ObjC language support. Another route is simply to avoid doing the check that it's being done right now and simply try to the create the exception breakpoint for whatever language that is not in the hardcoded list. I'm happy to do that if the reviewers think it's a good idea. As a note, the other possible place for adding this `SupportsExceptionBreakpoints` method is in `LanguageRuntime`. However, accessing it requires having a process, which is not always the case when invoking the `breakpoint set -E` command. The process might not be alive yet, so `Language` is a good second place for this. And as a final note, I don't want to make this `SupportsExceptionBreakpoints` complicated. I'm keeping it as simple as possible because it can easily evolve as it's not part of the public API.
|
@llvm/pr-subscribers-lldb Author: Walter Erquinigo (walter-erquinigo) ChangesCommandObjectBreakpoint has a harcoded list of languages for which exception breakpoints can be enabled. I'm making this a bit more generic so that my Mojo plugin can get this feature. Another route is simply to avoid doing the check that it's being done right now and simply try to the create the exception breakpoint for whatever language that is not in the hardcoded list. I'm happy to do that if the reviewers think it's a good idea. As a note, the other possible place for adding this And as a final note, I don't want to make this Full diff: https://github.com/llvm/llvm-project/pull/97675.diff 3 Files Affected:
diff --git a/lldb/include/lldb/Target/Language.h b/lldb/include/lldb/Target/Language.h
index ff7c60bf68bfc..9c2c765ce497f 100644
--- a/lldb/include/lldb/Target/Language.h
+++ b/lldb/include/lldb/Target/Language.h
@@ -245,7 +245,7 @@ class Language : public PluginInterface {
// a match. But we wouldn't want this to match AnotherA::my_function. The
// user is specifying a truncated path, not a truncated set of characters.
// This function does a language-aware comparison for those purposes.
- virtual bool DemangledNameContainsPath(llvm::StringRef path,
+ virtual bool DemangledNameContainsPath(llvm::StringRef path,
ConstString demangled) const;
// if a language has a custom format for printing variable declarations that
@@ -363,6 +363,10 @@ class Language : public PluginInterface {
return false;
}
+ /// Returns true if this Language supports exception breakpoints via a
+ /// corresponding LanguageRuntime plugin.
+ virtual bool SupportsExceptionBreakpoints() const { return false; }
+
protected:
// Classes that inherit from Language can see and modify these
diff --git a/lldb/source/Commands/CommandObjectBreakpoint.cpp b/lldb/source/Commands/CommandObjectBreakpoint.cpp
index cd4c7790f447e..a5fe9273fac76 100644
--- a/lldb/source/Commands/CommandObjectBreakpoint.cpp
+++ b/lldb/source/Commands/CommandObjectBreakpoint.cpp
@@ -308,9 +308,6 @@ class CommandObjectBreakpointSet : public CommandObjectParsed {
case eLanguageTypeC_plus_plus_14:
m_exception_language = eLanguageTypeC_plus_plus;
break;
- case eLanguageTypeObjC:
- m_exception_language = eLanguageTypeObjC;
- break;
case eLanguageTypeObjC_plus_plus:
error_context =
"Set exception breakpoints separately for c++ and objective-c";
@@ -319,6 +316,12 @@ class CommandObjectBreakpointSet : public CommandObjectParsed {
error_context = "Unknown language type for exception breakpoint";
break;
default:
+ if (Language *languagePlugin = Language::FindPlugin(language)) {
+ if (languagePlugin->SupportsExceptionBreakpoints()) {
+ m_exception_language = language;
+ break;
+ }
+ }
error_context = "Unsupported language type for exception breakpoint";
}
if (!error_context.empty())
diff --git a/lldb/source/Plugins/Language/ObjC/ObjCLanguage.h b/lldb/source/Plugins/Language/ObjC/ObjCLanguage.h
index a50f4b036108d..a61d0f128370d 100644
--- a/lldb/source/Plugins/Language/ObjC/ObjCLanguage.h
+++ b/lldb/source/Plugins/Language/ObjC/ObjCLanguage.h
@@ -194,6 +194,8 @@ class ObjCLanguage : public Language {
llvm::StringRef GetInstanceVariableName() override { return "self"; }
+ bool SupportsExceptionBreakpoints() const override { return true; }
+
// PluginInterface protocol
llvm::StringRef GetPluginName() override { return GetPluginNameStatic(); }
};
|
And does this list include languages that are not plugin provided? I was wondering why only Objective C changed, but if the rest are not plugins then this makes sense. |
lldb/include/lldb/Target/Language.h
Outdated
| @@ -245,7 +245,7 @@ class Language : public PluginInterface { | |||
| // a match. But we wouldn't want this to match AnotherA::my_function. The | |||
| // user is specifying a truncated path, not a truncated set of characters. | |||
| // This function does a language-aware comparison for those purposes. | |||
| virtual bool DemangledNameContainsPath(llvm::StringRef path, | |||
| virtual bool DemangledNameContainsPath(llvm::StringRef path, | |||
| @@ -319,6 +316,12 @@ class CommandObjectBreakpointSet : public CommandObjectParsed { | |||
| error_context = "Unknown language type for exception breakpoint"; | |||
| break; | |||
| default: | |||
| if (Language *languagePlugin = Language::FindPlugin(language)) { | |||
There was a problem hiding this comment.
You could drop the braces from the first if I think, but this is already in so many sets of braces I'd keep them for clarity's sake.
There was a problem hiding this comment.
Within switch statements I tend to be very paranoid with braces
The hardcoded list in the file being changes includes C++ and Objc in its various variants.
That was the only simple example I could use to show how this change does work. Thanks for the review! |
As a minor follow up for #97675, I'm renaming `SupportsExceptionBreakpoints` to `SupportsExceptionBreakpointsOnThrow` and adding a `SupportsExceptionBreakpointsOnCatch` to have a bit of more granularity.
…lvm#97675) CommandObjectBreakpoint has a harcoded list of languages for which exception breakpoints can be enabled. I'm making this a bit more generic so that my Mojo plugin can get this feature. Basically, I'm adding a new overridable method `Language::SupportsExceptionBreakpoints` that can be used by language plugins to determine whether they support this feature or not. This method is used in addition to the hardcoded list and, as an example, I'm using it for the ObjC language support. Another route is simply to avoid doing the check that it's being done right now and simply try to the create the exception breakpoint for whatever language that is not in the hardcoded list. I'm happy to do that if the reviewers think it's a good idea. As a note, the other possible place for adding this `SupportsExceptionBreakpoints` method is in `LanguageRuntime`. However, accessing it requires having a process, which is not always the case when invoking the `breakpoint set -E` command. The process might not be alive yet, so `Language` is a good second place for this. And as a final note, I don't want to make this `SupportsExceptionBreakpoints` complicated. I'm keeping it as simple as possible because it can easily evolve as it's not part of the public API.
As a minor follow up for llvm#97675, I'm renaming `SupportsExceptionBreakpoints` to `SupportsExceptionBreakpointsOnThrow` and adding a `SupportsExceptionBreakpointsOnCatch` to have a bit of more granularity.
Exception Breakpoints are created by the static method LanguageRuntime::CreateExceptionBreakpoint. So they don't require a process. Exception breakpoint resolvers can be "resolver discovering resolvers". This used to be necessary when there were two ObjC runtimes possible on MacOS X, and you couldn't necessarily tell which one was going to be used till the program till it ran. So they are able to adjust themselves when their Target launches a process. It's a little awkward to have a static method in LanguageRuntime that makes the Exception breakpoint conditioned by a Language method 'SupportsExceptionBreakpoint".
|
Indeed, but let me elaborate. What I need is a method that doesn't require a process that could tell me if a certain language can support exception breakpoints, as that's what the checks in the Then I had two main choices w.r.t
I somewhat agree with it, but probably I'd end up writing a static method |
CommandObjectBreakpoint has a harcoded list of languages for which exception breakpoints can be enabled. I'm making this a bit more generic so that my Mojo plugin can get this feature.
Basically, I'm adding a new overridable method
Language::SupportsExceptionBreakpointsthat can be used by language plugins to determine whether they support this feature or not. This method is used in addition to the hardcoded list and, as an example, I'm using it for the ObjC language support.Another route is simply to avoid doing the check that it's being done right now and simply try to the create the exception breakpoint for whatever language that is not in the hardcoded list. I'm happy to do that if the reviewers think it's a good idea.
As a note, the other possible place for adding this
SupportsExceptionBreakpointsmethod is inLanguageRuntime. However, accessing it requires having a process, which is not always the case when invoking thebreakpoint set -Ecommand. The process might not be alive yet, soLanguageis a good second place for this.And as a final note, I don't want to make this
SupportsExceptionBreakpointscomplicated. I'm keeping it as simple as possible because it can easily evolve as it's not part of the public API.