compiler: Fix compute_int and sizeof for cross compilation.

sizeof now uses compute_int which again binary searches for correct value.

3 files changed, 44 insertions, 33 deletions

diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index d1a564b..403dda1 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -998,37 +998,43 @@ class CCompiler(Compiler):
         mlog.debug(se)
         return RunResult(True, pe.returncode, so, se)
 
-    def _bisect_compiles(self, t, fargs, env, extra_args, dependencies):
-        # FIXME: Does not actually do bisection right now
-        for i in range(1, 1024):
-            fargs['size'] = i
-            if self.compiles(t.format(**fargs), env, extra_args, dependencies):
-                if self.id == 'msvc':
-                    # MSVC refuses to construct an array of zero size, so
-                    # the test only succeeds when i is sizeof(element) + 1
-                    return i - 1
-                return i
-        raise EnvironmentException('Cross-compile check overflowed')
-
-    def cross_compute_int(self, fragment, prefix, env, extra_args=None, dependencies=None):
-        if extra_args is None:
-            extra_args = []
-        fargs = {'prefix': prefix, 'fragment': fragment}
+    def _compile_int(self, expression, prefix, env, extra_args, dependencies):
+        fargs = {'prefix': prefix, 'expression': expression}
         t = '''#include <stdio.h>
         {prefix}
-        int temparray[{size}-({fragment})];'''
-        return self._bisect_compiles(t, fargs, env, extra_args, dependencies)
+        int main() {{ static int a[1-2*!({expression})]; a[0]=0; return 0; }}'''
+        return self.compiles(t.format(**fargs), env, extra_args, dependencies)
+
+    def cross_compute_int(self, expression, l, h, guess, prefix, env, extra_args, dependencies):
+        if isinstance(guess, int):
+            if self._compile_int('%s == %d' % (expression, guess), prefix, env, extra_args, dependencies):
+                return guess
 
-    def compute_int(self, fragment, prefix, env, extra_args=None, dependencies=None):
+        cur = l
+        while l < h:
+            cur = int((l + h) / 2)
+            if cur == l:
+                break
+
+            if self._compile_int('%s >= %d' % (expression, cur), prefix, env, extra_args, dependencies):
+                l = cur
+            else:
+                h = cur
+
+        if self._compile_int('%s == %d' % (expression, cur), prefix, env, extra_args, dependencies):
+            return cur
+        raise EnvironmentException('Cross-compile check overflowed')
+
+    def compute_int(self, expression, l, h, guess, prefix, env, extra_args=None, dependencies=None):
         if extra_args is None:
             extra_args = []
-        fargs = {'prefix': prefix, 'fragment': fragment}
         if self.is_cross:
-            return self.cross_compute_int(fragment, prefix, env, extra_args, dependencies)
+            return self.cross_compute_int(expression, l, h, guess, prefix, env, extra_args, dependencies)
+        fargs = {'prefix': prefix, 'expression': expression}
         t = '''#include<stdio.h>
         {prefix}
         int main(int argc, char **argv) {{
-            printf("%ld\\n", (long)({fragment}));
+            printf("%ld\\n", (long)({expression}));
             return 0;
         }};'''
         res = self.run(t.format(**fargs), env, extra_args, dependencies)
@@ -1049,10 +1055,7 @@ class CCompiler(Compiler):
         }}'''
         if not self.compiles(t.format(**fargs), env, extra_args, dependencies):
             return -1
-        t = '''#include <stdio.h>
-        {prefix}
-        int temparray[{size}-sizeof({name})];'''
-        return self._bisect_compiles(t, fargs, env, extra_args, dependencies)
+        return self.cross_compute_int('sizeof(%s)' % element, 1, 128, None, prefix, env, extra_args, dependencies)
 
     def sizeof(self, element, prefix, env, extra_args=None, dependencies=None):
         if extra_args is None:
@@ -1087,9 +1090,8 @@ class CCompiler(Compiler):
         struct tmp {{
             char c;
             {type} target;
-        }};
-        int testarray[{size}-offsetof(struct tmp, target)];'''
-        return self._bisect_compiles(t, fargs, env, extra_args, dependencies)
+        }};'''
+        return self.cross_compute_int('offsetof(struct tmp, target)', 1, 1024, None, t.format(**fargs), env, extra_args, dependencies)
 
     def alignment(self, typename, env, extra_args=None, dependencies=None):
         if extra_args is None:
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index dca7934..bd818bb 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -827,14 +827,23 @@ class CompilerHolder(InterpreterObject):
         if len(args) != 1:
             raise InterpreterException('Compute_int takes exactly one argument.')
         check_stringlist(args)
-        fragment = args[0]
+        expression = args[0]
         prefix = kwargs.get('prefix', '')
+        l = kwargs.get('low', -1024)
+        h = kwargs.get('high', 1024)
+        guess = kwargs.get('guess', None)
         if not isinstance(prefix, str):
             raise InterpreterException('Prefix argument of compute_int must be a string.')
+        if not isinstance(l, int):
+            raise InterpreterException('Low argument of compute_int must be an int.')
+        if not isinstance(h, int):
+            raise InterpreterException('High argument of compute_int must be an int.')
+        if guess is not None and not isinstance(guess, int):
+            raise InterpreterException('Guess argument of compute_int must be an int.')
         extra_args = self.determine_args(kwargs)
         deps = self.determine_dependencies(kwargs)
-        res = self.compiler.compute_int(fragment, prefix, self.environment, extra_args, deps)
-        mlog.log('Computing int of "%s": %d' % (fragment, res))
+        res = self.compiler.compute_int(expression, l, h, guess, prefix, self.environment, extra_args, deps)
+        mlog.log('Computing int of "%s": %d' % (expression, res))
         return res
 
     def sizeof_method(self, args, kwargs):
diff --git a/test cases/common/139 compute int/meson.build b/test cases/common/139 compute int/meson.build
index 6f813c5..43553fe 100644
--- a/test cases/common/139 compute int/meson.build
+++ b/test cases/common/139 compute int/meson.build
@@ -5,7 +5,7 @@ inc = include_directories('.')
 # Test with C
 cc = meson.get_compiler('c')
 
-intsize = cc.compute_int('sizeof(int)')
+intsize = cc.compute_int('sizeof(int)', low : 1, high : 16, guess : 4)
 foobar = cc.compute_int('FOOBAR_IN_FOOBAR_H', prefix : '#include "foobar.h"', include_directories : inc)
 
 cd = configuration_data()