analyzer: fix -Wanalyzer-allocation-size false +ve on Linux kernel's round_up macro [PR113654]

gcc/analyzer/ChangeLog:
	PR analyzer/113654
	* region-model.cc (is_round_up): New.
	(is_multiple_p): New.
	(is_dubious_capacity): New.
	(region_model::check_region_size): Move usage of size_visitor into
	is_dubious_capacity.

gcc/testsuite/ChangeLog:
	PR analyzer/113654
	* c-c++-common/analyzer/allocation-size-pr113654-1.c: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/gcc/testsuite/c-c++-common/analyzer/allocation-size-pr113654-1.c b/gcc/testsuite/c-c++-common/analyzer/allocation-size-pr113654-1.c
new file mode 100644
index 0000000..b7bfc5f
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/analyzer/allocation-size-pr113654-1.c
@@ -0,0 +1,52 @@
+/* Adapted from include/linux/math.h  */
+#define __round_mask(x, y) ((__typeof__(x))((y)-1))
+#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
+
+/* Reduced from Linux kernel's drivers/gpu/drm/i915/display/intel_bios.c  */
+typedef unsigned short u16;
+typedef unsigned int u32;
+typedef unsigned long __kernel_size_t;
+typedef __kernel_size_t size_t;
+
+extern __attribute__((__alloc_size__(1))) __attribute__((__malloc__))
+void* kzalloc(size_t size);
+
+typedef struct
+{
+  u32 reg;
+} i915_reg_t;
+struct intel_uncore;
+struct intel_uncore_funcs
+{
+  u32 (*mmio_readl)(struct intel_uncore* uncore, i915_reg_t r);
+};
+struct intel_uncore
+{
+  void* regs;
+  struct intel_uncore_funcs funcs;
+};
+static inline __attribute__((__gnu_inline__)) __attribute__((__unused__))
+__attribute__((no_instrument_function)) u32
+intel_uncore_read(struct intel_uncore* uncore, i915_reg_t reg)
+{
+  return uncore->funcs.mmio_readl(uncore, reg);
+}
+struct drm_i915_private
+{
+  struct intel_uncore uncore;
+};
+struct vbt_header*
+spi_oprom_get_vbt(struct drm_i915_private* i915)
+{
+  u16 vbt_size;
+  u32* vbt;
+  vbt_size =
+    intel_uncore_read(&i915->uncore, ((const i915_reg_t){ .reg = (0x102040) }));
+  vbt_size &= 0xffff;
+  vbt = (u32*)kzalloc(round_up (vbt_size, 4)); /* { dg-bogus "allocated buffer size is not a multiple of the pointee's size" "PR analyzer/113654" } */
+  if (!vbt)
+    goto err_not_found;
+  return (struct vbt_header*)vbt;
+err_not_found:
+  return ((struct vbt_header*)0);
+}