initial checkin of SJLJ exception handling runtime

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8235 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 246 insertions, 0 deletions

diff --git a/runtime/GCCLibraries/crtend/SJLJ-Exception.cpp b/runtime/GCCLibraries/crtend/SJLJ-Exception.cpp
new file mode 100644
index 0000000000..fea2d4128f
--- /dev/null
+++ b/runtime/GCCLibraries/crtend/SJLJ-Exception.cpp
@@ -0,0 +1,123 @@
+
+#include "SJLJ-Exception.h"
+#include <cstdlib>
+#include <cassert>
+
+inline llvm_sjlj_exception *get_sjlj_exception(llvm_exception *E) {
+  assert(E->ExceptionType == SJLJException);
+  return (llvm_sjlj_exception*)(E+1) - 1;
+}
+
+// SetJmpMapEntry - One entry in a linked list of setjmps for the current
+// function.
+struct SetJmpMapEntry {
+  void *JmpBuf;
+  unsigned SetJmpID;
+  SetJmpMapEntry *Next;
+};
+
+static void SJLJDestructor(llvm_exception *E) {
+  free(get_sjlj_exception(E));
+}
+
+
+// __llvm_sjljeh_throw_longjmp - This function creates the longjmp exception and
+// returns.  It takes care of mapping the longjmp value from 0 -> 1 as
+// appropriate.  The caller should immediately call llvm.unwind after this
+// function call.
+void __llvm_sjljeh_throw_longjmp(void *JmpBuffer, int Val) throw() {
+  llvm_sjlj_exception *E =
+    (llvm_sjlj_exception *)malloc(sizeof(llvm_sjlj_exception));
+  E->BaseException.ExceptionDestructor = SJLJDestructor;
+  E->BaseException.ExceptionType = SJLJException;
+  E->BaseException.HandlerCount = 0;
+  E->BaseException.isRethrown = 0;
+  E->JmpBuffer = JmpBuffer;
+  E->LongJmpValue = Val ? Val : 1;
+
+  __llvm_eh_add_uncaught_exception(&E->BaseException);
+}
+
+// __llvm_sjljeh_init_setjmpmap - This funciton initializes the pointer provided
+// to an empty setjmp map, and should be called on entry to a function which
+// calls setjmp.
+void __llvm_sjljeh_init_setjmpmap(void **SetJmpMap) throw() {
+  *SetJmpMap = 0;
+}
+
+// __llvm_sjljeh_destroy_setjmpmap - This function frees all memory associated
+// with the specified setjmpmap structure.  It should be called on all exits
+// (returns or unwinds) from the function which calls ...init_setjmpmap.
+void __llvm_sjljeh_destroy_setjmpmap(void **SetJmpMap) throw() {
+  SetJmpMapEntry *Next;
+  for (SetJmpMapEntry *SJE = *(SetJmpMapEntry**)SetJmpMap; SJE; SJE = Next) {
+    Next = SJE->Next;
+    free(SJE);
+  }
+}
+
+// __llvm_sjljeh_add_setjmp_to_map - This function adds or updates an entry to
+// the map, to indicate which setjmp should be returned to if a longjmp happens.
+void __llvm_sjljeh_add_setjmp_to_map(void **SetJmpMap, void *JmpBuf,
+                                     unsigned SetJmpID) throw() {
+  SetJmpMapEntry **SJE = (SetJmpMapEntry**)SetJmpMap;
+
+  // Scan for a pre-existing entry...
+  for (; *SJE; SJE = &(*SJE)->Next)
+    if ((*SJE)->JmpBuf == JmpBuf) {
+      (*SJE)->SetJmpID = SetJmpID;
+      return;
+    }
+
+  // No prexisting entry found, append to the end of the list...
+  SetJmpMapEntry *New = (SetJmpMapEntry *)malloc(sizeof(SetJmpMapEntry));
+  *SJE = New;
+  New->JmpBuf = JmpBuf;
+  New->SetJmpID = SetJmpID;
+  New->Next = 0;
+}
+
+// __llvm_sjljeh_is_longjmp_exception - This function returns true if the
+// current uncaught exception is a longjmp exception.  This is the first step of
+// catching a sjlj exception.
+bool __llvm_sjljeh_is_longjmp_exception() throw() {
+  return __llvm_eh_current_uncaught_exception_type(SJLJException) != 0;
+}
+  
+// __llvm_sjljeh_get_longjmp_value - This function returns the value that the
+// setjmp call should "return".  This requires that the current uncaught
+// exception be a sjlj exception, though it does not require the exception to be
+// caught by this function.
+int __llvm_sjljeh_get_longjmp_value() throw() {
+  llvm_sjlj_exception *E =
+    get_sjlj_exception(__llvm_eh_get_uncaught_exception());
+  return E->LongJmpValue;
+}
+
+// __llvm_sjljeh_try_catching_longjmp_exception - This function checks to see if
+// the current uncaught longjmp exception matches any of the setjmps collected
+// in the setjmpmap structure.  If so, it catches and destroys the exception,
+// returning the index of the setjmp which caught the exception.  If not, it
+// leaves the exception uncaught and returns a value of ~0.
+unsigned __llvm_sjljeh_try_catching_longjmp_exception(void **SetJmpMap) throw(){
+  llvm_sjlj_exception *E =
+    get_sjlj_exception(__llvm_eh_get_uncaught_exception());
+ 
+  // Scan for a matching entry in the SetJmpMap...
+  SetJmpMapEntry *SJE = *(SetJmpMapEntry**)SetJmpMap;
+  for (; SJE; SJE = SJE->Next)
+    if (SJE->JmpBuf == E->JmpBuffer) {
+      // "Catch" and destroy the exception...
+      __llvm_eh_pop_from_uncaught_stack();
+
+      // We know it's a longjmp exception, so we can just free it instead of
+      // calling the destructor.
+      free(E);
+
+      // Return the setjmp ID which we should branch to...
+      return SJE->SetJmpID;
+    }
+  
+  // No setjmp in this function catches the exception!
+  return ~0;
+}
diff --git a/runtime/GCCLibraries/libexception/SJLJ-Exception.cpp b/runtime/GCCLibraries/libexception/SJLJ-Exception.cpp
new file mode 100644
index 0000000000..fea2d4128f
--- /dev/null
+++ b/runtime/GCCLibraries/libexception/SJLJ-Exception.cpp
@@ -0,0 +1,123 @@
+
+#include "SJLJ-Exception.h"
+#include <cstdlib>
+#include <cassert>
+
+inline llvm_sjlj_exception *get_sjlj_exception(llvm_exception *E) {
+  assert(E->ExceptionType == SJLJException);
+  return (llvm_sjlj_exception*)(E+1) - 1;
+}
+
+// SetJmpMapEntry - One entry in a linked list of setjmps for the current
+// function.
+struct SetJmpMapEntry {
+  void *JmpBuf;
+  unsigned SetJmpID;
+  SetJmpMapEntry *Next;
+};
+
+static void SJLJDestructor(llvm_exception *E) {
+  free(get_sjlj_exception(E));
+}
+
+
+// __llvm_sjljeh_throw_longjmp - This function creates the longjmp exception and
+// returns.  It takes care of mapping the longjmp value from 0 -> 1 as
+// appropriate.  The caller should immediately call llvm.unwind after this
+// function call.
+void __llvm_sjljeh_throw_longjmp(void *JmpBuffer, int Val) throw() {
+  llvm_sjlj_exception *E =
+    (llvm_sjlj_exception *)malloc(sizeof(llvm_sjlj_exception));
+  E->BaseException.ExceptionDestructor = SJLJDestructor;
+  E->BaseException.ExceptionType = SJLJException;
+  E->BaseException.HandlerCount = 0;
+  E->BaseException.isRethrown = 0;
+  E->JmpBuffer = JmpBuffer;
+  E->LongJmpValue = Val ? Val : 1;
+
+  __llvm_eh_add_uncaught_exception(&E->BaseException);
+}
+
+// __llvm_sjljeh_init_setjmpmap - This funciton initializes the pointer provided
+// to an empty setjmp map, and should be called on entry to a function which
+// calls setjmp.
+void __llvm_sjljeh_init_setjmpmap(void **SetJmpMap) throw() {
+  *SetJmpMap = 0;
+}
+
+// __llvm_sjljeh_destroy_setjmpmap - This function frees all memory associated
+// with the specified setjmpmap structure.  It should be called on all exits
+// (returns or unwinds) from the function which calls ...init_setjmpmap.
+void __llvm_sjljeh_destroy_setjmpmap(void **SetJmpMap) throw() {
+  SetJmpMapEntry *Next;
+  for (SetJmpMapEntry *SJE = *(SetJmpMapEntry**)SetJmpMap; SJE; SJE = Next) {
+    Next = SJE->Next;
+    free(SJE);
+  }
+}
+
+// __llvm_sjljeh_add_setjmp_to_map - This function adds or updates an entry to
+// the map, to indicate which setjmp should be returned to if a longjmp happens.
+void __llvm_sjljeh_add_setjmp_to_map(void **SetJmpMap, void *JmpBuf,
+                                     unsigned SetJmpID) throw() {
+  SetJmpMapEntry **SJE = (SetJmpMapEntry**)SetJmpMap;
+
+  // Scan for a pre-existing entry...
+  for (; *SJE; SJE = &(*SJE)->Next)
+    if ((*SJE)->JmpBuf == JmpBuf) {
+      (*SJE)->SetJmpID = SetJmpID;
+      return;
+    }
+
+  // No prexisting entry found, append to the end of the list...
+  SetJmpMapEntry *New = (SetJmpMapEntry *)malloc(sizeof(SetJmpMapEntry));
+  *SJE = New;
+  New->JmpBuf = JmpBuf;
+  New->SetJmpID = SetJmpID;
+  New->Next = 0;
+}
+
+// __llvm_sjljeh_is_longjmp_exception - This function returns true if the
+// current uncaught exception is a longjmp exception.  This is the first step of
+// catching a sjlj exception.
+bool __llvm_sjljeh_is_longjmp_exception() throw() {
+  return __llvm_eh_current_uncaught_exception_type(SJLJException) != 0;
+}
+  
+// __llvm_sjljeh_get_longjmp_value - This function returns the value that the
+// setjmp call should "return".  This requires that the current uncaught
+// exception be a sjlj exception, though it does not require the exception to be
+// caught by this function.
+int __llvm_sjljeh_get_longjmp_value() throw() {
+  llvm_sjlj_exception *E =
+    get_sjlj_exception(__llvm_eh_get_uncaught_exception());
+  return E->LongJmpValue;
+}
+
+// __llvm_sjljeh_try_catching_longjmp_exception - This function checks to see if
+// the current uncaught longjmp exception matches any of the setjmps collected
+// in the setjmpmap structure.  If so, it catches and destroys the exception,
+// returning the index of the setjmp which caught the exception.  If not, it
+// leaves the exception uncaught and returns a value of ~0.
+unsigned __llvm_sjljeh_try_catching_longjmp_exception(void **SetJmpMap) throw(){
+  llvm_sjlj_exception *E =
+    get_sjlj_exception(__llvm_eh_get_uncaught_exception());
+ 
+  // Scan for a matching entry in the SetJmpMap...
+  SetJmpMapEntry *SJE = *(SetJmpMapEntry**)SetJmpMap;
+  for (; SJE; SJE = SJE->Next)
+    if (SJE->JmpBuf == E->JmpBuffer) {
+      // "Catch" and destroy the exception...
+      __llvm_eh_pop_from_uncaught_stack();
+
+      // We know it's a longjmp exception, so we can just free it instead of
+      // calling the destructor.
+      free(E);
+
+      // Return the setjmp ID which we should branch to...
+      return SJE->SetJmpID;
+    }
+  
+  // No setjmp in this function catches the exception!
+  return ~0;
+}