Add C++ exception support for __cxa_rethrow (#3996)

I have added custom calls that can be later used by Unity SDK for capturing C++ exceptions on iOS. Also, when the current exception is NULL (during the std::terminate call) the sentrycrashsc_initSelfThread call is made to enrich the stack trace. Co-authored-by: Philipp Hofmann <philipp.hofmann@sentry.io>
getsentry · May 22, 2024 · cf97209 · cf97209
1 parent b11cd87
commit cf97209
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Features
+
+- Add C++ exception support for `__cxa_rethrow` (#3996)
+
 ### Improvements
 
 - Stop FramesTracker when app is in background (#3979)

diff --git a/Samples/macOS-Swift/macOS-Swift/Base.lproj/Main.storyboard b/Samples/macOS-Swift/macOS-Swift/Base.lproj/Main.storyboard
@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.Storyboard.XIB" version="3.0" toolsVersion="19455" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" initialViewController="B8D-0N-5wS">
+<document type="com.apple.InterfaceBuilder3.Cocoa.Storyboard.XIB" version="3.0" toolsVersion="32700.99.1234" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" initialViewController="B8D-0N-5wS">
     <dependencies>
         <deployment identifier="macosx"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="19455"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="22690"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <scenes>
@@ -711,10 +711,10 @@
                         <autoresizingMask key="autoresizingMask"/>
                         <subviews>
                             <stackView distribution="fill" orientation="vertical" alignment="centerX" spacing="12" horizontalStackHuggingPriority="249.99998474121094" verticalStackHuggingPriority="249.99998474121094" fixedFrame="YES" detachesHiddenViews="YES" translatesAutoresizingMaskIntoConstraints="NO" id="fsa-9g-bf3">
-                                <rect key="frame" x="161" y="59" width="164" height="244"/>
+                                <rect key="frame" x="161" y="27" width="224" height="276"/>
                                 <subviews>
                                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="nAm-U5-PON">
-                                        <rect key="frame" x="14" y="217" width="136" height="32"/>
+                                        <rect key="frame" x="44" y="249" width="136" height="32"/>
                                         <buttonCell key="cell" type="push" title="Add Breadcrumb" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="zk9-d6-mm1">
                                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                                             <font key="font" metaFont="system"/>
@@ -724,7 +724,7 @@
                                         </connections>
                                     </button>
                                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="dzU-Gi-2VZ">
-                                        <rect key="frame" x="12" y="185" width="141" height="32"/>
+                                        <rect key="frame" x="42" y="217" width="141" height="32"/>
                                         <buttonCell key="cell" type="push" title="Capture Message" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="EQH-kc-eDD">
                                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                                             <font key="font" metaFont="system"/>
@@ -734,7 +734,7 @@
                                         </connections>
                                     </button>
                                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="Ocz-Nk-ZQ2">
-                                        <rect key="frame" x="-7" y="153" width="178" height="32"/>
+                                        <rect key="frame" x="23" y="185" width="178" height="32"/>
                                         <buttonCell key="cell" type="push" title="Capture User Feedback" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="nui-gg-F5o">
                                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                                             <font key="font" metaFont="system"/>
@@ -744,7 +744,7 @@
                                         </connections>
                                     </button>
                                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="GQW-jy-1TZ">
-                                        <rect key="frame" x="4" y="121" width="156" height="32"/>
+                                        <rect key="frame" x="34" y="153" width="156" height="32"/>
                                         <buttonCell key="cell" type="push" title="_crashOnException:" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="7rF-ep-EYR">
                                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                                             <font key="font" metaFont="system"/>
@@ -754,7 +754,7 @@
                                         </buttonCell>
                                     </button>
                                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="c5W-zA-19P">
-                                        <rect key="frame" x="7" y="89" width="150" height="32"/>
+                                        <rect key="frame" x="37" y="121" width="150" height="32"/>
                                         <buttonCell key="cell" type="push" title="captureTransaction" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="OVU-vi-LRM">
                                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                                             <font key="font" metaFont="system"/>
@@ -764,7 +764,7 @@
                                         </connections>
                                     </button>
                                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="0rS-ee-VAF">
-                                        <rect key="frame" x="22" y="57" width="120" height="32"/>
+                                        <rect key="frame" x="52" y="89" width="120" height="32"/>
                                         <buttonCell key="cell" type="push" title="Sentry.crash()" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="k1V-IH-Ru7">
                                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                                             <font key="font" metaFont="system"/>
@@ -774,7 +774,7 @@
                                         </connections>
                                     </button>
                                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="sxu-g3-vT7" userLabel="CppException">
-                                        <rect key="frame" x="21" y="25" width="123" height="32"/>
+                                        <rect key="frame" x="51" y="57" width="123" height="32"/>
                                         <buttonCell key="cell" type="push" title="CPP Exception" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="B4S-qm-cMV">
                                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                                             <font key="font" metaFont="system"/>
@@ -783,8 +783,18 @@
                                             <action selector="cppException:" target="XfG-lQ-9wD" id="mIk-IE-HEb"/>
                                         </connections>
                                     </button>
+                                    <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="Cfu-21-l6L" userLabel="CppException">
+                                        <rect key="frame" x="-7" y="25" width="238" height="32"/>
+                                        <buttonCell key="cell" type="push" title="Rethrow No Active CPP Exception" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="YRN-qy-qrz">
+                                            <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
+                                            <font key="font" metaFont="system"/>
+                                            <connections>
+                                                <action selector="rethrowNoActiveCppException:" target="XfG-lQ-9wD" id="fGo-DY-Pj9"/>
+                                            </connections>
+                                        </buttonCell>
+                                    </button>
                                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="onh-qf-HCq" userLabel="asyncCrash">
-                                        <rect key="frame" x="29" y="-7" width="107" height="32"/>
+                                        <rect key="frame" x="59" y="-7" width="107" height="32"/>
                                         <buttonCell key="cell" type="push" title="async crash" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="3ec-oQ-wXv">
                                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                                             <font key="font" metaFont="system"/>
@@ -803,6 +813,7 @@
                                     <integer value="1000"/>
                                     <integer value="1000"/>
                                     <integer value="1000"/>
+                                    <integer value="1000"/>
                                 </visibilityPriorities>
                                 <customSpacing>
                                     <real value="3.4028234663852886e+38"/>
@@ -813,6 +824,7 @@
                                     <real value="3.4028234663852886e+38"/>
                                     <real value="3.4028234663852886e+38"/>
                                     <real value="3.4028234663852886e+38"/>
+                                    <real value="3.4028234663852886e+38"/>
                                 </customSpacing>
                             </stackView>
                         </subviews>

diff --git a/Samples/macOS-Swift/macOS-Swift/CppSample.cpp b/Samples/macOS-Swift/macOS-Swift/CppSample.cpp
@@ -12,3 +12,11 @@ Sentry::CppSample::throwCPPException(void)
 {
     internalFunction();
 }
+
+void
+Sentry::CppSample::rethrowNoActiveCPPException(void)
+{
+    // Rethrowing an exception when there is no active exception will lead to std::terminate being
+    // called.
+    throw;
+}
diff --git a/Samples/macOS-Swift/macOS-Swift/CppSample.hpp b/Samples/macOS-Swift/macOS-Swift/CppSample.hpp
@@ -8,6 +8,7 @@ namespace Sentry {
 class CppSample {
 public:
     void throwCPPException();
+    void rethrowNoActiveCPPException();
 };
 }
 

diff --git a/Samples/macOS-Swift/macOS-Swift/CppWrapper.h b/Samples/macOS-Swift/macOS-Swift/CppWrapper.h
@@ -2,4 +2,5 @@
 
 @interface CppWrapper : NSObject
 - (void)throwCPPException;
+- (void)rethrowNoActiveCPPException;
 @end
diff --git a/Samples/macOS-Swift/macOS-Swift/CppWrapper.m b/Samples/macOS-Swift/macOS-Swift/CppWrapper.m
@@ -10,4 +10,10 @@ - (void)throwCPPException
     cppTool.throwCPPException();
 }
 
+- (void)rethrowNoActiveCPPException
+{
+    Sentry::CppSample cppTool;
+    cppTool.rethrowNoActiveCPPException();
+}
+
 @end
diff --git a/Samples/macOS-Swift/macOS-Swift/ViewController.swift b/Samples/macOS-Swift/macOS-Swift/ViewController.swift
@@ -53,6 +53,10 @@ class ViewController: NSViewController {
         wrapper.throwCPPException()
     }
 
+    @IBAction func rethrowNoActiveCppException(_ sender: Any) {
+        let wrapper = CppWrapper()
+        wrapper.rethrowNoActiveCPPException()
+    }
     @IBAction func asyncCrash(_ sender: Any) {
         DispatchQueue.main.async {
             self.asyncCrash1()

diff --git a/Sources/SentryCrash/Recording/Monitors/SentryCrashMonitor_CPPException.cpp b/Sources/SentryCrash/Recording/Monitors/SentryCrashMonitor_CPPException.cpp
@@ -72,6 +72,7 @@ static SentryCrashStackCursor g_stackCursor;
 // ============================================================================
 
 typedef void (*cxa_throw_type)(void *, std::type_info *, void (*)(void *));
+typedef void (*cxa_rethrow_type)(void);
 
 extern "C" {
 void __cxa_throw(void *thrown_exception, std::type_info *tinfo, void (*dest)(void *))
@@ -92,6 +93,28 @@ __cxa_throw(void *thrown_exception, std::type_info *tinfo, void (*dest)(void *))
     orig_cxa_throw(thrown_exception, tinfo, dest);
     __builtin_unreachable();
 }
+
+void
+__sentry_cxa_throw(void *thrown_exception, std::type_info *tinfo, void (*dest)(void *))
+{
+    __cxa_throw(thrown_exception, tinfo, dest);
+}
+
+void
+__sentry_cxa_rethrow()
+{
+    if (g_captureNextStackTrace) {
+        sentrycrashsc_initSelfThread(&g_stackCursor, 1);
+    }
+
+    static cxa_rethrow_type orig_cxa_rethrow = NULL;
+    unlikely_if(orig_cxa_rethrow == NULL)
+    {
+        orig_cxa_rethrow = (cxa_rethrow_type)dlsym(RTLD_NEXT, "__cxa_rethrow");
+    }
+    orig_cxa_rethrow();
+    __builtin_unreachable();
+}
 }
 
 void
@@ -127,33 +150,39 @@ CPPExceptionTerminate(void)
         const char *description = descriptionBuff;
         descriptionBuff[0] = 0;
 
-        SentryCrashLOG_DEBUG("Discovering what kind of exception was thrown.");
-        g_captureNextStackTrace = false;
-        try {
-            throw;
-        } catch (std::exception &exc) {
-            strncpy(descriptionBuff, exc.what(), sizeof(descriptionBuff));
-        }
+        std::exception_ptr currException = std::current_exception();
+        if (currException == NULL) {
+            SentryCrashLOG_DEBUG("Terminate without exception.");
+            sentrycrashsc_initSelfThread(&g_stackCursor, 0);
+        } else {
+            SentryCrashLOG_DEBUG("Discovering what kind of exception was thrown.");
+            g_captureNextStackTrace = false;
+            try {
+                throw;
+            } catch (std::exception &exc) {
+                strncpy(descriptionBuff, exc.what(), sizeof(descriptionBuff));
+            }
 #define CATCH_VALUE(TYPE, PRINTFTYPE)                                                              \
     catch (TYPE value) {                                                                           \
         snprintf(descriptionBuff, sizeof(descriptionBuff), "%" #PRINTFTYPE, value);                \
     }
-        CATCH_VALUE(char, d)
-        CATCH_VALUE(short, d)
-        CATCH_VALUE(int, d)
-        CATCH_VALUE(long, ld)
-        CATCH_VALUE(long long, lld)
-        CATCH_VALUE(unsigned char, u)
-        CATCH_VALUE(unsigned short, u)
-        CATCH_VALUE(unsigned int, u)
-        CATCH_VALUE(unsigned long, lu)
-        CATCH_VALUE(unsigned long long, llu)
-        CATCH_VALUE(float, f)
-        CATCH_VALUE(double, f)
-        CATCH_VALUE(long double, Lf)
-        CATCH_VALUE(char *, s)
-        catch (...) { description = NULL; }
-        g_captureNextStackTrace = g_isEnabled;
+            CATCH_VALUE(char, d)
+            CATCH_VALUE(short, d)
+            CATCH_VALUE(int, d)
+            CATCH_VALUE(long, ld)
+            CATCH_VALUE(long long, lld)
+            CATCH_VALUE(unsigned char, u)
+            CATCH_VALUE(unsigned short, u)
+            CATCH_VALUE(unsigned int, u)
+            CATCH_VALUE(unsigned long, lu)
+            CATCH_VALUE(unsigned long long, llu)
+            CATCH_VALUE(float, f)
+            CATCH_VALUE(double, f)
+            CATCH_VALUE(long double, Lf)
+            CATCH_VALUE(char *, s)
+            catch (...) { description = NULL; }
+            g_captureNextStackTrace = g_isEnabled;
+        }
 
         // TODO: Should this be done here? Maybe better in the exception
         // handler?
-Original file line number
+Diff line change
@@ Expand Up / @@ -8,6 +8,7 @@ namespace Sentry { @@
     class CppSample {
     public:
         void throwCPPException();
+        void rethrowNoActiveCPPException();
     };
     }
@@ Expand Down @@