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Commit 0a280a0d authored by Jack Palevich's avatar Jack Palevich
Browse files

Remove use of setjmp/longjmp from libacc compiler. 

It makes it harder to deal with memory allocation.

Also fix bug in the otcc-ansi.c test, where the wrong part of the
code buffer was being mprotected, so that if the code buffer happened
to be allocated across a page boundary, some code would no receive
execute permission.
parent 6f5fb6fd

libacc/acc.cpp

+47 −34
Original line number Diff line number Diff line
@@ -11,7 +11,6 @@ 
#include <ctype.h>

#include <dlfcn.h>

#include <errno.h>

#include <setjmp.h>

#include <stdarg.h>

#include <stdint.h>

#include <stdio.h>
@@ -69,6 +68,7 @@ class Compiler : public ErrorSink { 
        char* pProgramBase;

        ErrorSink* mErrorSink;

        int mSize;

        bool mOverflowed;



        void release() {

            if (pProgramBase != 0) {
@@ -77,13 +77,16 @@ class Compiler : public ErrorSink { 
            }

        }



        void check(int n) {

        bool check(int n) {

            int newSize = ind - pProgramBase + n;

            if (newSize > mSize) {

            bool overflow = newSize > mSize;

            if (overflow && !mOverflowed) {

                mOverflowed = true;

                if (mErrorSink) {

                    mErrorSink->error("Code too large: %d bytes", newSize);

                }

            }

            return overflow;

        }



    public:
@@ -92,6 +95,7 @@ class Compiler : public ErrorSink { 
            ind = 0;

            mErrorSink = 0;

            mSize = 0;

            mOverflowed = false;

        }



        ~CodeBuf() {
@@ -110,7 +114,9 @@ class Compiler : public ErrorSink { 
        }



        int o4(int n) {

            check(4);

            if(check(4)) {

                return 0;

            }

            intptr_t result = (intptr_t) ind;

            * (int*) ind = n;

            ind += 4;
@@ -121,7 +127,9 @@ class Compiler : public ErrorSink { 
         * Output a byte. Handles all values, 0..ff.

         */

        void ob(int n) {

            check(1);

            if(check(1)) {

                return;

            }

            *ind++ = n;

        }
@@ -1037,6 +1045,7 @@ class Compiler : public ErrorSink { 
        int decodeOp(int op) {

            if (op < 0 || op > OP_COUNT) {

                error("Out-of-range operator: %d\n", op);

                op = 0;

            }

            return operatorHelper[op];

        }
@@ -1363,8 +1372,6 @@ class Compiler : public ErrorSink { 


    String mErrorBuf;



    jmp_buf mErrorRecoveryJumpBuf;



    String mPragmas;

    int mPragmaStringCount;
@@ -1430,6 +1437,7 @@ class Compiler : public ErrorSink { 
    void pdef(int t) {

        if (dstk - sym_stk >= ALLOC_SIZE) {

            error("Symbol table exhausted");

            return;

        }

        *dstk++ = t;

    }
@@ -1475,7 +1483,6 @@ class Compiler : public ErrorSink { 
                } else {

                    error("Unsupported preprocessor directive \"%s\"", last_id);

                }



            }

            inp();

        }
@@ -1609,6 +1616,7 @@ class Compiler : public ErrorSink { 
        if (ch == '(') {

            delete pName;

            error("Defines with arguments not supported");

            return;

        }

        while (isspace(ch)) {

            inp();
@@ -1669,7 +1677,6 @@ class Compiler : public ErrorSink { 
        mErrorBuf.printf("%ld: ", file->getLine());

        mErrorBuf.vprintf(fmt, ap);

        mErrorBuf.printf("\n");

        longjmp(mErrorRecoveryJumpBuf, 1);

    }



    void skip(intptr_t c) {
@@ -2053,6 +2060,7 @@ class Compiler : public ErrorSink { 
    char* allocGlobalSpace(int bytes) {

        if (glo - pGlobalBase + bytes > ALLOC_SIZE) {

            error("Global space exhausted");

            return NULL;

        }

        char* result = glo;

        glo += bytes;
@@ -2132,9 +2140,10 @@ class Compiler : public ErrorSink { 
        }

        if (pGen == NULL) {

            error("No code generator defined.");

        }

        } else {

            pGen->setErrorSink(this);

        }

    }



public:

    struct args {
@@ -2154,7 +2163,7 @@ public: 


    int compile(const char* text, size_t textLength) {

        int result;

        if (! (result = setjmp(mErrorRecoveryJumpBuf))) {



        cleanup();

        clear();

        codeBuf.init(ALLOC_SIZE);
@@ -2178,6 +2187,10 @@ public: 
        next();

        globalDeclarations();

        result = pGen->finishCompile();

        if (result == 0) {

            if (mErrorBuf.len()) {

                result = -2;

            }

        }

        return result;

    }

libacc/tests/data/otcc-ansi.c

+1 −1
Original line number Diff line number Diff line
@@ -450,7 +450,7 @@ int main(int g, int e) { 
    o();

    ad();

    ab(0);

    if (mprotect((ac + 592) & (~ 4095), (99999 + 4095) & (~ 4095), 7)) {

    if (mprotect(ac & (~ 4095), (99999 + 4095) & (~ 4095), 7)) {

        printf("Mprotect failed. %d\n", errno);

        return -1;

    }