Import compiler-rt trunk r224034.vendor/compiler-rt/compiler-rt-r224034

https://llvm.org/svn/llvm-project/compiler-rt/trunk@224034

1 files changed, 249 insertions, 0 deletions

diff --git a/lib/builtins/gcc_personality_v0.c b/lib/builtins/gcc_personality_v0.c
new file mode 100644
index 000000000000..869f4178e853
--- /dev/null
+++ b/lib/builtins/gcc_personality_v0.c
@@ -0,0 +1,249 @@
+/* ===-- gcc_personality_v0.c - Implement __gcc_personality_v0 -------------===
+ *
+ *      	       The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ *
+ */
+
+#include "int_lib.h"
+
+/*
+ * _Unwind_* stuff based on C++ ABI public documentation
+ * http://refspecs.freestandards.org/abi-eh-1.21.html
+ */
+
+typedef enum {
+    _URC_NO_REASON = 0,
+    _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
+    _URC_FATAL_PHASE2_ERROR = 2,
+    _URC_FATAL_PHASE1_ERROR = 3,
+    _URC_NORMAL_STOP = 4,
+    _URC_END_OF_STACK = 5,
+    _URC_HANDLER_FOUND = 6,
+    _URC_INSTALL_CONTEXT = 7,
+    _URC_CONTINUE_UNWIND = 8
+} _Unwind_Reason_Code;
+
+typedef enum {
+    _UA_SEARCH_PHASE = 1,
+    _UA_CLEANUP_PHASE = 2,
+    _UA_HANDLER_FRAME = 4,
+    _UA_FORCE_UNWIND = 8,
+    _UA_END_OF_STACK = 16
+} _Unwind_Action;
+
+typedef struct _Unwind_Context* _Unwind_Context_t;
+
+struct _Unwind_Exception {
+    uint64_t                exception_class;
+    void                    (*exception_cleanup)(_Unwind_Reason_Code reason, 
+                                                 struct _Unwind_Exception* exc);
+    uintptr_t                private_1;    
+    uintptr_t                private_2;    
+};
+
+COMPILER_RT_ABI  const uint8_t*    _Unwind_GetLanguageSpecificData(_Unwind_Context_t c);
+COMPILER_RT_ABI  void              _Unwind_SetGR(_Unwind_Context_t c, int i, uintptr_t n);
+COMPILER_RT_ABI  void              _Unwind_SetIP(_Unwind_Context_t, uintptr_t new_value);
+COMPILER_RT_ABI  uintptr_t         _Unwind_GetIP(_Unwind_Context_t context);
+COMPILER_RT_ABI  uintptr_t         _Unwind_GetRegionStart(_Unwind_Context_t context);
+
+
+/*
+ * Pointer encodings documented at:
+ *   http://refspecs.freestandards.org/LSB_1.3.0/gLSB/gLSB/ehframehdr.html
+ */
+
+#define DW_EH_PE_omit      0xff  /* no data follows */
+
+#define DW_EH_PE_absptr    0x00
+#define DW_EH_PE_uleb128   0x01
+#define DW_EH_PE_udata2    0x02
+#define DW_EH_PE_udata4    0x03
+#define DW_EH_PE_udata8    0x04
+#define DW_EH_PE_sleb128   0x09
+#define DW_EH_PE_sdata2    0x0A
+#define DW_EH_PE_sdata4    0x0B
+#define DW_EH_PE_sdata8    0x0C
+
+#define DW_EH_PE_pcrel     0x10
+#define DW_EH_PE_textrel   0x20
+#define DW_EH_PE_datarel   0x30
+#define DW_EH_PE_funcrel   0x40
+#define DW_EH_PE_aligned   0x50  
+#define DW_EH_PE_indirect  0x80 /* gcc extension */
+
+
+
+/* read a uleb128 encoded value and advance pointer */
+static uintptr_t readULEB128(const uint8_t** data)
+{
+    uintptr_t result = 0;
+    uintptr_t shift = 0;
+    unsigned char byte;
+    const uint8_t* p = *data;
+    do {
+        byte = *p++;
+        result |= (byte & 0x7f) << shift;
+        shift += 7;
+    } while (byte & 0x80);
+    *data = p;
+    return result;
+}
+
+/* read a pointer encoded value and advance pointer */
+static uintptr_t readEncodedPointer(const uint8_t** data, uint8_t encoding)
+{
+    const uint8_t* p = *data;
+    uintptr_t result = 0;
+
+    if ( encoding == DW_EH_PE_omit ) 
+        return 0;
+
+    /* first get value */
+    switch (encoding & 0x0F) {
+        case DW_EH_PE_absptr:
+            result = *((const uintptr_t*)p);
+            p += sizeof(uintptr_t);
+            break;
+        case DW_EH_PE_uleb128:
+            result = readULEB128(&p);
+            break;
+        case DW_EH_PE_udata2:
+            result = *((const uint16_t*)p);
+            p += sizeof(uint16_t);
+            break;
+        case DW_EH_PE_udata4:
+            result = *((const uint32_t*)p);
+            p += sizeof(uint32_t);
+            break;
+        case DW_EH_PE_udata8:
+            result = *((const uint64_t*)p);
+            p += sizeof(uint64_t);
+            break;
+        case DW_EH_PE_sdata2:
+            result = *((const int16_t*)p);
+            p += sizeof(int16_t);
+            break;
+        case DW_EH_PE_sdata4:
+            result = *((const int32_t*)p);
+            p += sizeof(int32_t);
+            break;
+        case DW_EH_PE_sdata8:
+            result = *((const int64_t*)p);
+            p += sizeof(int64_t);
+            break;
+        case DW_EH_PE_sleb128:
+        default:
+            /* not supported */
+            compilerrt_abort();
+            break;
+    }
+
+    /* then add relative offset */
+    switch ( encoding & 0x70 ) {
+        case DW_EH_PE_absptr:
+            /* do nothing */
+            break;
+        case DW_EH_PE_pcrel:
+            result += (uintptr_t)(*data);
+            break;
+        case DW_EH_PE_textrel:
+        case DW_EH_PE_datarel:
+        case DW_EH_PE_funcrel:
+        case DW_EH_PE_aligned:
+        default:
+            /* not supported */
+            compilerrt_abort();
+            break;
+    }
+
+    /* then apply indirection */
+    if (encoding & DW_EH_PE_indirect) {
+        result = *((const uintptr_t*)result);
+    }
+
+    *data = p;
+    return result;
+}
+
+
+/*
+ * The C compiler makes references to __gcc_personality_v0 in
+ * the dwarf unwind information for translation units that use
+ * __attribute__((cleanup(xx))) on local variables.
+ * This personality routine is called by the system unwinder
+ * on each frame as the stack is unwound during a C++ exception
+ * throw through a C function compiled with -fexceptions.
+ */
+#if __USING_SJLJ_EXCEPTIONS__
+// the setjump-longjump based exceptions personality routine has a different name
+COMPILER_RT_ABI _Unwind_Reason_Code
+__gcc_personality_sj0(int version, _Unwind_Action actions,
+         uint64_t exceptionClass, struct _Unwind_Exception* exceptionObject,
+         _Unwind_Context_t context)
+#else
+COMPILER_RT_ABI _Unwind_Reason_Code
+__gcc_personality_v0(int version, _Unwind_Action actions,
+         uint64_t exceptionClass, struct _Unwind_Exception* exceptionObject,
+         _Unwind_Context_t context)
+#endif
+{
+    /* Since C does not have catch clauses, there is nothing to do during */
+    /* phase 1 (the search phase). */
+    if ( actions & _UA_SEARCH_PHASE ) 
+        return _URC_CONTINUE_UNWIND;
+        
+    /* There is nothing to do if there is no LSDA for this frame. */
+    const uint8_t* lsda = _Unwind_GetLanguageSpecificData(context);
+    if ( lsda == (uint8_t*) 0 )
+        return _URC_CONTINUE_UNWIND;
+
+    uintptr_t pc = _Unwind_GetIP(context)-1;
+    uintptr_t funcStart = _Unwind_GetRegionStart(context);
+    uintptr_t pcOffset = pc - funcStart;
+
+    /* Parse LSDA header. */
+    uint8_t lpStartEncoding = *lsda++;
+    if (lpStartEncoding != DW_EH_PE_omit) {
+        readEncodedPointer(&lsda, lpStartEncoding); 
+    }
+    uint8_t ttypeEncoding = *lsda++;
+    if (ttypeEncoding != DW_EH_PE_omit) {
+        readULEB128(&lsda);  
+    }
+    /* Walk call-site table looking for range that includes current PC. */
+    uint8_t         callSiteEncoding = *lsda++;
+    uint32_t        callSiteTableLength = readULEB128(&lsda);
+    const uint8_t*  callSiteTableStart = lsda;
+    const uint8_t*  callSiteTableEnd = callSiteTableStart + callSiteTableLength;
+    const uint8_t* p=callSiteTableStart;
+    while (p < callSiteTableEnd) {
+        uintptr_t start = readEncodedPointer(&p, callSiteEncoding);
+        uintptr_t length = readEncodedPointer(&p, callSiteEncoding);
+        uintptr_t landingPad = readEncodedPointer(&p, callSiteEncoding);
+        readULEB128(&p); /* action value not used for C code */
+        if ( landingPad == 0 )
+            continue; /* no landing pad for this entry */
+        if ( (start <= pcOffset) && (pcOffset < (start+length)) ) {
+            /* Found landing pad for the PC.
+             * Set Instruction Pointer to so we re-enter function 
+             * at landing pad. The landing pad is created by the compiler
+             * to take two parameters in registers.
+	     */
+            _Unwind_SetGR(context, __builtin_eh_return_data_regno(0), 
+                                                (uintptr_t)exceptionObject);
+            _Unwind_SetGR(context, __builtin_eh_return_data_regno(1), 0);
+            _Unwind_SetIP(context, funcStart+landingPad);
+            return _URC_INSTALL_CONTEXT;
+        }
+    }
+    
+    /* No landing pad found, continue unwinding. */
+    return _URC_CONTINUE_UNWIND;
+}
+