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[Windows] Implement PrintStackTrace(FILE*)
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llvm::sys::PrintBacktrace(FILE*) is supposed to print a backtrace
of the current thread given the current PC.  This function was
unimplemented on Windows, and instead the only time we could
print a backtrace was as the result of an exception through
LLVMUnhandledExceptionFilter.

This patch implements backtracing of self by using
RtlCaptureContext to get a CONTEXT for the current thread, and
moving the printing and StackWalk64 code to a common method that
printing own stack trace and printing stack trace of an exception
can use.

Differential Revision: http://reviews.llvm.org/D8068
Reviewed by: Reid Kleckner

llvm-svn: 231382
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Zachary Turner committed Mar 5, 2015
1 parent e4b9213 commit 62b7b61
Showing 1 changed file with 104 additions and 81 deletions.
185 changes: 104 additions & 81 deletions llvm/lib/Support/Windows/Signals.inc
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Expand Up @@ -10,7 +10,6 @@
// This file provides the Win32 specific implementation of the Signals class.
//
//===----------------------------------------------------------------------===//

#include "llvm/Support/FileSystem.h"
#include <algorithm>
#include <signal.h>
Expand Down Expand Up @@ -173,6 +172,89 @@ static PTOP_LEVEL_EXCEPTION_FILTER OldFilter = NULL;
// globals which this critical section addresses.
static CRITICAL_SECTION CriticalSection;

static void PrintStackTraceForThread(FILE *File, HANDLE hProcess,
HANDLE hThread, STACKFRAME64 &StackFrame,
CONTEXT *Context) {
DWORD machineType;
#if defined(_M_X64)
machineType = IMAGE_FILE_MACHINE_AMD64;
#else
machineType = IMAGE_FILE_MACHINE_I386;
#endif

// Initialize the symbol handler.
SymSetOptions(SYMOPT_DEFERRED_LOADS | SYMOPT_LOAD_LINES);
SymInitialize(hProcess, NULL, TRUE);

while (true) {
if (!StackWalk64(machineType, hProcess, hThread, &StackFrame, Context, NULL,
SymFunctionTableAccess64, SymGetModuleBase64, NULL)) {
break;
}

if (StackFrame.AddrFrame.Offset == 0)
break;

// Print the PC in hexadecimal.
DWORD64 PC = StackFrame.AddrPC.Offset;
#if defined(_M_X64)
fprintf(File, "0x%016llX", PC);
#elif defined(_M_IX86)
fprintf(File, "0x%08lX", static_cast<DWORD>(PC));
#endif

// Print the parameters. Assume there are four.
#if defined(_M_X64)
fprintf(File, " (0x%016llX 0x%016llX 0x%016llX 0x%016llX)",
StackFrame.Params[0], StackFrame.Params[1], StackFrame.Params[2],
StackFrame.Params[3]);
#elif defined(_M_IX86)
fprintf(File, " (0x%08lX 0x%08lX 0x%08lX 0x%08lX)",
static_cast<DWORD>(StackFrame.Params[0]),
static_cast<DWORD>(StackFrame.Params[1]),
static_cast<DWORD>(StackFrame.Params[2]),
static_cast<DWORD>(StackFrame.Params[3]));
#endif
// Verify the PC belongs to a module in this process.
if (!SymGetModuleBase64(hProcess, PC)) {
fputs(" <unknown module>\n", File);
continue;
}

// Print the symbol name.
char buffer[512];
IMAGEHLP_SYMBOL64 *symbol = reinterpret_cast<IMAGEHLP_SYMBOL64 *>(buffer);
memset(symbol, 0, sizeof(IMAGEHLP_SYMBOL64));
symbol->SizeOfStruct = sizeof(IMAGEHLP_SYMBOL64);
symbol->MaxNameLength = 512 - sizeof(IMAGEHLP_SYMBOL64);

DWORD64 dwDisp;
if (!SymGetSymFromAddr64(hProcess, PC, &dwDisp, symbol)) {
fputc('\n', File);
continue;
}

buffer[511] = 0;
if (dwDisp > 0)
fprintf(File, ", %s() + 0x%llX bytes(s)", symbol->Name, dwDisp);
else
fprintf(File, ", %s", symbol->Name);

// Print the source file and line number information.
IMAGEHLP_LINE64 line;
DWORD dwLineDisp;
memset(&line, 0, sizeof(line));
line.SizeOfStruct = sizeof(line);
if (SymGetLineFromAddr64(hProcess, PC, &dwLineDisp, &line)) {
fprintf(File, ", %s, line %lu", line.FileName, line.LineNumber);
if (dwLineDisp > 0)
fprintf(File, " + 0x%lX byte(s)", dwLineDisp);
}

fputc('\n', File);
}
}

namespace llvm {

//===----------------------------------------------------------------------===//
Expand Down Expand Up @@ -299,8 +381,25 @@ void sys::PrintStackTraceOnErrorSignal() {
LeaveCriticalSection(&CriticalSection);
}

void llvm::sys::PrintStackTrace(FILE *) {
// FIXME: Implement.
void llvm::sys::PrintStackTrace(FILE *File) {

STACKFRAME64 StackFrame = {0};
CONTEXT Context = {0};
::RtlCaptureContext(&Context);
#if defined(_M_X64)
StackFrame.AddrPC.Offset = Context.Rip;
StackFrame.AddrStack.Offset = Context.Rsp;
StackFrame.AddrFrame.Offset = Context.Rbp;
#else
StackFrame.AddrPC.Offset = Context.Eip;
StackFrame.AddrStack.Offset = Context.Esp;
StackFrame.AddrFrame.Offset = Context.Ebp;
#endif
StackFrame.AddrPC.Mode = AddrModeFlat;
StackFrame.AddrStack.Mode = AddrModeFlat;
StackFrame.AddrFrame.Mode = AddrModeFlat;
PrintStackTraceForThread(File, GetCurrentProcess(), GetCurrentThread(),
StackFrame, &Context);
}


Expand Down Expand Up @@ -356,17 +455,14 @@ static LONG WINAPI LLVMUnhandledExceptionFilter(LPEXCEPTION_POINTERS ep) {
STACKFRAME64 StackFrame;
memset(&StackFrame, 0, sizeof(StackFrame));

DWORD machineType;
#if defined(_M_X64)
machineType = IMAGE_FILE_MACHINE_AMD64;
StackFrame.AddrPC.Offset = ep->ContextRecord->Rip;
StackFrame.AddrPC.Mode = AddrModeFlat;
StackFrame.AddrStack.Offset = ep->ContextRecord->Rsp;
StackFrame.AddrStack.Mode = AddrModeFlat;
StackFrame.AddrFrame.Offset = ep->ContextRecord->Rbp;
StackFrame.AddrFrame.Mode = AddrModeFlat;
#elif defined(_M_IX86)
machineType = IMAGE_FILE_MACHINE_I386;
StackFrame.AddrPC.Offset = ep->ContextRecord->Eip;
StackFrame.AddrPC.Mode = AddrModeFlat;
StackFrame.AddrStack.Offset = ep->ContextRecord->Esp;
Expand All @@ -377,81 +473,8 @@ static LONG WINAPI LLVMUnhandledExceptionFilter(LPEXCEPTION_POINTERS ep) {

HANDLE hProcess = GetCurrentProcess();
HANDLE hThread = GetCurrentThread();

// Initialize the symbol handler.
SymSetOptions(SYMOPT_DEFERRED_LOADS|SYMOPT_LOAD_LINES);
SymInitialize(hProcess, NULL, TRUE);

while (true) {
if (!StackWalk64(machineType, hProcess, hThread, &StackFrame,
ep->ContextRecord, NULL, SymFunctionTableAccess64,
SymGetModuleBase64, NULL)) {
break;
}

if (StackFrame.AddrFrame.Offset == 0)
break;

// Print the PC in hexadecimal.
DWORD64 PC = StackFrame.AddrPC.Offset;
#if defined(_M_X64)
fprintf(stderr, "0x%016llX", PC);
#elif defined(_M_IX86)
fprintf(stderr, "0x%08lX", static_cast<DWORD>(PC));
#endif

// Print the parameters. Assume there are four.
#if defined(_M_X64)
fprintf(stderr, " (0x%016llX 0x%016llX 0x%016llX 0x%016llX)",
StackFrame.Params[0],
StackFrame.Params[1],
StackFrame.Params[2],
StackFrame.Params[3]);
#elif defined(_M_IX86)
fprintf(stderr, " (0x%08lX 0x%08lX 0x%08lX 0x%08lX)",
static_cast<DWORD>(StackFrame.Params[0]),
static_cast<DWORD>(StackFrame.Params[1]),
static_cast<DWORD>(StackFrame.Params[2]),
static_cast<DWORD>(StackFrame.Params[3]));
#endif
// Verify the PC belongs to a module in this process.
if (!SymGetModuleBase64(hProcess, PC)) {
fputs(" <unknown module>\n", stderr);
continue;
}

// Print the symbol name.
char buffer[512];
IMAGEHLP_SYMBOL64 *symbol = reinterpret_cast<IMAGEHLP_SYMBOL64 *>(buffer);
memset(symbol, 0, sizeof(IMAGEHLP_SYMBOL64));
symbol->SizeOfStruct = sizeof(IMAGEHLP_SYMBOL64);
symbol->MaxNameLength = 512 - sizeof(IMAGEHLP_SYMBOL64);

DWORD64 dwDisp;
if (!SymGetSymFromAddr64(hProcess, PC, &dwDisp, symbol)) {
fputc('\n', stderr);
continue;
}

buffer[511] = 0;
if (dwDisp > 0)
fprintf(stderr, ", %s() + 0x%llX bytes(s)", symbol->Name, dwDisp);
else
fprintf(stderr, ", %s", symbol->Name);

// Print the source file and line number information.
IMAGEHLP_LINE64 line;
DWORD dwLineDisp;
memset(&line, 0, sizeof(line));
line.SizeOfStruct = sizeof(line);
if (SymGetLineFromAddr64(hProcess, PC, &dwLineDisp, &line)) {
fprintf(stderr, ", %s, line %lu", line.FileName, line.LineNumber);
if (dwLineDisp > 0)
fprintf(stderr, " + 0x%lX byte(s)", dwLineDisp);
}

fputc('\n', stderr);
}
PrintStackTraceForThread(stderr, hProcess, hThread, StackFrame,
ep->ContextRecord);

_exit(ep->ExceptionRecord->ExceptionCode);
}
Expand Down

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